59908aead531e6257ad63f1767cf736c82585956
[linux-2.6.git] / drivers / scsi / libiscsi.c
1 /*
2  * iSCSI lib functions
3  *
4  * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
5  * Copyright (C) 2004 - 2006 Mike Christie
6  * Copyright (C) 2004 - 2005 Dmitry Yusupov
7  * Copyright (C) 2004 - 2005 Alex Aizman
8  * maintained by open-iscsi@googlegroups.com
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23  */
24 #include <linux/types.h>
25 #include <linux/kfifo.h>
26 #include <linux/delay.h>
27 #include <linux/log2.h>
28 #include <asm/unaligned.h>
29 #include <net/tcp.h>
30 #include <scsi/scsi_cmnd.h>
31 #include <scsi/scsi_device.h>
32 #include <scsi/scsi_eh.h>
33 #include <scsi/scsi_tcq.h>
34 #include <scsi/scsi_host.h>
35 #include <scsi/scsi.h>
36 #include <scsi/iscsi_proto.h>
37 #include <scsi/scsi_transport.h>
38 #include <scsi/scsi_transport_iscsi.h>
39 #include <scsi/libiscsi.h>
40
41 static int iscsi_dbg_lib;
42 module_param_named(debug_libiscsi, iscsi_dbg_lib, int, S_IRUGO | S_IWUSR);
43 MODULE_PARM_DESC(debug_libiscsi, "Turn on debugging for libiscsi module. "
44                  "Set to 1 to turn on, and zero to turn off. Default "
45                  "is off.");
46
47 #define ISCSI_DBG_CONN(_conn, dbg_fmt, arg...)                  \
48         do {                                                    \
49                 if (iscsi_dbg_lib)                              \
50                         iscsi_conn_printk(KERN_INFO, _conn,     \
51                                              "%s " dbg_fmt,     \
52                                              __func__, ##arg);  \
53         } while (0);
54
55 #define ISCSI_DBG_SESSION(_session, dbg_fmt, arg...)                    \
56         do {                                                            \
57                 if (iscsi_dbg_lib)                                      \
58                         iscsi_session_printk(KERN_INFO, _session,       \
59                                              "%s " dbg_fmt,             \
60                                              __func__, ##arg);          \
61         } while (0);
62
63 /* Serial Number Arithmetic, 32 bits, less than, RFC1982 */
64 #define SNA32_CHECK 2147483648UL
65
66 static int iscsi_sna_lt(u32 n1, u32 n2)
67 {
68         return n1 != n2 && ((n1 < n2 && (n2 - n1 < SNA32_CHECK)) ||
69                             (n1 > n2 && (n2 - n1 < SNA32_CHECK)));
70 }
71
72 /* Serial Number Arithmetic, 32 bits, less than, RFC1982 */
73 static int iscsi_sna_lte(u32 n1, u32 n2)
74 {
75         return n1 == n2 || ((n1 < n2 && (n2 - n1 < SNA32_CHECK)) ||
76                             (n1 > n2 && (n2 - n1 < SNA32_CHECK)));
77 }
78
79 inline void iscsi_conn_queue_work(struct iscsi_conn *conn)
80 {
81         struct Scsi_Host *shost = conn->session->host;
82         struct iscsi_host *ihost = shost_priv(shost);
83
84         if (ihost->workq)
85                 queue_work(ihost->workq, &conn->xmitwork);
86 }
87 EXPORT_SYMBOL_GPL(iscsi_conn_queue_work);
88
89 void
90 iscsi_update_cmdsn(struct iscsi_session *session, struct iscsi_nopin *hdr)
91 {
92         uint32_t max_cmdsn = be32_to_cpu(hdr->max_cmdsn);
93         uint32_t exp_cmdsn = be32_to_cpu(hdr->exp_cmdsn);
94
95         /*
96          * standard specifies this check for when to update expected and
97          * max sequence numbers
98          */
99         if (iscsi_sna_lt(max_cmdsn, exp_cmdsn - 1))
100                 return;
101
102         if (exp_cmdsn != session->exp_cmdsn &&
103             !iscsi_sna_lt(exp_cmdsn, session->exp_cmdsn))
104                 session->exp_cmdsn = exp_cmdsn;
105
106         if (max_cmdsn != session->max_cmdsn &&
107             !iscsi_sna_lt(max_cmdsn, session->max_cmdsn)) {
108                 session->max_cmdsn = max_cmdsn;
109                 /*
110                  * if the window closed with IO queued, then kick the
111                  * xmit thread
112                  */
113                 if (!list_empty(&session->leadconn->cmdqueue) ||
114                     !list_empty(&session->leadconn->mgmtqueue))
115                         iscsi_conn_queue_work(session->leadconn);
116         }
117 }
118 EXPORT_SYMBOL_GPL(iscsi_update_cmdsn);
119
120 /**
121  * iscsi_prep_data_out_pdu - initialize Data-Out
122  * @task: scsi command task
123  * @r2t: R2T info
124  * @hdr: iscsi data in pdu
125  *
126  * Notes:
127  *      Initialize Data-Out within this R2T sequence and finds
128  *      proper data_offset within this SCSI command.
129  *
130  *      This function is called with connection lock taken.
131  **/
132 void iscsi_prep_data_out_pdu(struct iscsi_task *task, struct iscsi_r2t_info *r2t,
133                            struct iscsi_data *hdr)
134 {
135         struct iscsi_conn *conn = task->conn;
136         unsigned int left = r2t->data_length - r2t->sent;
137
138         task->hdr_len = sizeof(struct iscsi_data);
139
140         memset(hdr, 0, sizeof(struct iscsi_data));
141         hdr->ttt = r2t->ttt;
142         hdr->datasn = cpu_to_be32(r2t->datasn);
143         r2t->datasn++;
144         hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
145         memcpy(hdr->lun, task->lun, sizeof(hdr->lun));
146         hdr->itt = task->hdr_itt;
147         hdr->exp_statsn = r2t->exp_statsn;
148         hdr->offset = cpu_to_be32(r2t->data_offset + r2t->sent);
149         if (left > conn->max_xmit_dlength) {
150                 hton24(hdr->dlength, conn->max_xmit_dlength);
151                 r2t->data_count = conn->max_xmit_dlength;
152                 hdr->flags = 0;
153         } else {
154                 hton24(hdr->dlength, left);
155                 r2t->data_count = left;
156                 hdr->flags = ISCSI_FLAG_CMD_FINAL;
157         }
158         conn->dataout_pdus_cnt++;
159 }
160 EXPORT_SYMBOL_GPL(iscsi_prep_data_out_pdu);
161
162 static int iscsi_add_hdr(struct iscsi_task *task, unsigned len)
163 {
164         unsigned exp_len = task->hdr_len + len;
165
166         if (exp_len > task->hdr_max) {
167                 WARN_ON(1);
168                 return -EINVAL;
169         }
170
171         WARN_ON(len & (ISCSI_PAD_LEN - 1)); /* caller must pad the AHS */
172         task->hdr_len = exp_len;
173         return 0;
174 }
175
176 /*
177  * make an extended cdb AHS
178  */
179 static int iscsi_prep_ecdb_ahs(struct iscsi_task *task)
180 {
181         struct scsi_cmnd *cmd = task->sc;
182         unsigned rlen, pad_len;
183         unsigned short ahslength;
184         struct iscsi_ecdb_ahdr *ecdb_ahdr;
185         int rc;
186
187         ecdb_ahdr = iscsi_next_hdr(task);
188         rlen = cmd->cmd_len - ISCSI_CDB_SIZE;
189
190         BUG_ON(rlen > sizeof(ecdb_ahdr->ecdb));
191         ahslength = rlen + sizeof(ecdb_ahdr->reserved);
192
193         pad_len = iscsi_padding(rlen);
194
195         rc = iscsi_add_hdr(task, sizeof(ecdb_ahdr->ahslength) +
196                            sizeof(ecdb_ahdr->ahstype) + ahslength + pad_len);
197         if (rc)
198                 return rc;
199
200         if (pad_len)
201                 memset(&ecdb_ahdr->ecdb[rlen], 0, pad_len);
202
203         ecdb_ahdr->ahslength = cpu_to_be16(ahslength);
204         ecdb_ahdr->ahstype = ISCSI_AHSTYPE_CDB;
205         ecdb_ahdr->reserved = 0;
206         memcpy(ecdb_ahdr->ecdb, cmd->cmnd + ISCSI_CDB_SIZE, rlen);
207
208         ISCSI_DBG_SESSION(task->conn->session,
209                           "iscsi_prep_ecdb_ahs: varlen_cdb_len %d "
210                           "rlen %d pad_len %d ahs_length %d iscsi_headers_size "
211                           "%u\n", cmd->cmd_len, rlen, pad_len, ahslength,
212                           task->hdr_len);
213         return 0;
214 }
215
216 static int iscsi_prep_bidi_ahs(struct iscsi_task *task)
217 {
218         struct scsi_cmnd *sc = task->sc;
219         struct iscsi_rlength_ahdr *rlen_ahdr;
220         int rc;
221
222         rlen_ahdr = iscsi_next_hdr(task);
223         rc = iscsi_add_hdr(task, sizeof(*rlen_ahdr));
224         if (rc)
225                 return rc;
226
227         rlen_ahdr->ahslength =
228                 cpu_to_be16(sizeof(rlen_ahdr->read_length) +
229                                                   sizeof(rlen_ahdr->reserved));
230         rlen_ahdr->ahstype = ISCSI_AHSTYPE_RLENGTH;
231         rlen_ahdr->reserved = 0;
232         rlen_ahdr->read_length = cpu_to_be32(scsi_in(sc)->length);
233
234         ISCSI_DBG_SESSION(task->conn->session,
235                           "bidi-in rlen_ahdr->read_length(%d) "
236                           "rlen_ahdr->ahslength(%d)\n",
237                           be32_to_cpu(rlen_ahdr->read_length),
238                           be16_to_cpu(rlen_ahdr->ahslength));
239         return 0;
240 }
241
242 /**
243  * iscsi_prep_scsi_cmd_pdu - prep iscsi scsi cmd pdu
244  * @task: iscsi task
245  *
246  * Prep basic iSCSI PDU fields for a scsi cmd pdu. The LLD should set
247  * fields like dlength or final based on how much data it sends
248  */
249 static int iscsi_prep_scsi_cmd_pdu(struct iscsi_task *task)
250 {
251         struct iscsi_conn *conn = task->conn;
252         struct iscsi_session *session = conn->session;
253         struct scsi_cmnd *sc = task->sc;
254         struct iscsi_cmd *hdr;
255         unsigned hdrlength, cmd_len;
256         itt_t itt;
257         int rc;
258
259         if (conn->session->tt->alloc_pdu) {
260                 rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_CMD);
261                 if (rc)
262                         return rc;
263         }
264         hdr = (struct iscsi_cmd *) task->hdr;
265         itt = hdr->itt;
266         memset(hdr, 0, sizeof(*hdr));
267
268         if (session->tt->parse_pdu_itt)
269                 hdr->itt = task->hdr_itt = itt;
270         else
271                 hdr->itt = task->hdr_itt = build_itt(task->itt,
272                                                      task->conn->session->age);
273         task->hdr_len = 0;
274         rc = iscsi_add_hdr(task, sizeof(*hdr));
275         if (rc)
276                 return rc;
277         hdr->opcode = ISCSI_OP_SCSI_CMD;
278         hdr->flags = ISCSI_ATTR_SIMPLE;
279         int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
280         memcpy(task->lun, hdr->lun, sizeof(task->lun));
281         hdr->cmdsn = task->cmdsn = cpu_to_be32(session->cmdsn);
282         session->cmdsn++;
283         hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
284         cmd_len = sc->cmd_len;
285         if (cmd_len < ISCSI_CDB_SIZE)
286                 memset(&hdr->cdb[cmd_len], 0, ISCSI_CDB_SIZE - cmd_len);
287         else if (cmd_len > ISCSI_CDB_SIZE) {
288                 rc = iscsi_prep_ecdb_ahs(task);
289                 if (rc)
290                         return rc;
291                 cmd_len = ISCSI_CDB_SIZE;
292         }
293         memcpy(hdr->cdb, sc->cmnd, cmd_len);
294
295         task->imm_count = 0;
296         if (scsi_bidi_cmnd(sc)) {
297                 hdr->flags |= ISCSI_FLAG_CMD_READ;
298                 rc = iscsi_prep_bidi_ahs(task);
299                 if (rc)
300                         return rc;
301         }
302         if (sc->sc_data_direction == DMA_TO_DEVICE) {
303                 unsigned out_len = scsi_out(sc)->length;
304                 struct iscsi_r2t_info *r2t = &task->unsol_r2t;
305
306                 hdr->data_length = cpu_to_be32(out_len);
307                 hdr->flags |= ISCSI_FLAG_CMD_WRITE;
308                 /*
309                  * Write counters:
310                  *
311                  *      imm_count       bytes to be sent right after
312                  *                      SCSI PDU Header
313                  *
314                  *      unsol_count     bytes(as Data-Out) to be sent
315                  *                      without R2T ack right after
316                  *                      immediate data
317                  *
318                  *      r2t data_length bytes to be sent via R2T ack's
319                  *
320                  *      pad_count       bytes to be sent as zero-padding
321                  */
322                 memset(r2t, 0, sizeof(*r2t));
323
324                 if (session->imm_data_en) {
325                         if (out_len >= session->first_burst)
326                                 task->imm_count = min(session->first_burst,
327                                                         conn->max_xmit_dlength);
328                         else
329                                 task->imm_count = min(out_len,
330                                                         conn->max_xmit_dlength);
331                         hton24(hdr->dlength, task->imm_count);
332                 } else
333                         zero_data(hdr->dlength);
334
335                 if (!session->initial_r2t_en) {
336                         r2t->data_length = min(session->first_burst, out_len) -
337                                                task->imm_count;
338                         r2t->data_offset = task->imm_count;
339                         r2t->ttt = cpu_to_be32(ISCSI_RESERVED_TAG);
340                         r2t->exp_statsn = cpu_to_be32(conn->exp_statsn);
341                 }
342
343                 if (!task->unsol_r2t.data_length)
344                         /* No unsolicit Data-Out's */
345                         hdr->flags |= ISCSI_FLAG_CMD_FINAL;
346         } else {
347                 hdr->flags |= ISCSI_FLAG_CMD_FINAL;
348                 zero_data(hdr->dlength);
349                 hdr->data_length = cpu_to_be32(scsi_in(sc)->length);
350
351                 if (sc->sc_data_direction == DMA_FROM_DEVICE)
352                         hdr->flags |= ISCSI_FLAG_CMD_READ;
353         }
354
355         /* calculate size of additional header segments (AHSs) */
356         hdrlength = task->hdr_len - sizeof(*hdr);
357
358         WARN_ON(hdrlength & (ISCSI_PAD_LEN-1));
359         hdrlength /= ISCSI_PAD_LEN;
360
361         WARN_ON(hdrlength >= 256);
362         hdr->hlength = hdrlength & 0xFF;
363
364         if (session->tt->init_task && session->tt->init_task(task))
365                 return -EIO;
366
367         task->state = ISCSI_TASK_RUNNING;
368
369         conn->scsicmd_pdus_cnt++;
370         ISCSI_DBG_SESSION(session, "iscsi prep [%s cid %d sc %p cdb 0x%x "
371                           "itt 0x%x len %d bidi_len %d cmdsn %d win %d]\n",
372                           scsi_bidi_cmnd(sc) ? "bidirectional" :
373                           sc->sc_data_direction == DMA_TO_DEVICE ?
374                           "write" : "read", conn->id, sc, sc->cmnd[0],
375                           task->itt, scsi_bufflen(sc),
376                           scsi_bidi_cmnd(sc) ? scsi_in(sc)->length : 0,
377                           session->cmdsn,
378                           session->max_cmdsn - session->exp_cmdsn + 1);
379         return 0;
380 }
381
382 /**
383  * iscsi_free_task - free a task
384  * @task: iscsi cmd task
385  *
386  * Must be called with session lock.
387  * This function returns the scsi command to scsi-ml or cleans
388  * up mgmt tasks then returns the task to the pool.
389  */
390 static void iscsi_free_task(struct iscsi_task *task)
391 {
392         struct iscsi_conn *conn = task->conn;
393         struct iscsi_session *session = conn->session;
394         struct scsi_cmnd *sc = task->sc;
395
396         ISCSI_DBG_SESSION(session, "freeing task itt 0x%x state %d sc %p\n",
397                           task->itt, task->state, task->sc);
398
399         session->tt->cleanup_task(task);
400         task->state = ISCSI_TASK_FREE;
401         task->sc = NULL;
402         /*
403          * login task is preallocated so do not free
404          */
405         if (conn->login_task == task)
406                 return;
407
408         __kfifo_put(session->cmdpool.queue, (void*)&task, sizeof(void*));
409
410         if (sc) {
411                 task->sc = NULL;
412                 /* SCSI eh reuses commands to verify us */
413                 sc->SCp.ptr = NULL;
414                 /*
415                  * queue command may call this to free the task, but
416                  * not have setup the sc callback
417                  */
418                 if (sc->scsi_done)
419                         sc->scsi_done(sc);
420         }
421 }
422
423 void __iscsi_get_task(struct iscsi_task *task)
424 {
425         atomic_inc(&task->refcount);
426 }
427 EXPORT_SYMBOL_GPL(__iscsi_get_task);
428
429 static void __iscsi_put_task(struct iscsi_task *task)
430 {
431         if (atomic_dec_and_test(&task->refcount))
432                 iscsi_free_task(task);
433 }
434
435 void iscsi_put_task(struct iscsi_task *task)
436 {
437         struct iscsi_session *session = task->conn->session;
438
439         spin_lock_bh(&session->lock);
440         __iscsi_put_task(task);
441         spin_unlock_bh(&session->lock);
442 }
443 EXPORT_SYMBOL_GPL(iscsi_put_task);
444
445 /**
446  * iscsi_complete_task - finish a task
447  * @task: iscsi cmd task
448  * @state: state to complete task with
449  *
450  * Must be called with session lock.
451  */
452 static void iscsi_complete_task(struct iscsi_task *task, int state)
453 {
454         struct iscsi_conn *conn = task->conn;
455
456         ISCSI_DBG_SESSION(conn->session,
457                           "complete task itt 0x%x state %d sc %p\n",
458                           task->itt, task->state, task->sc);
459         if (task->state == ISCSI_TASK_COMPLETED ||
460             task->state == ISCSI_TASK_ABRT_TMF ||
461             task->state == ISCSI_TASK_ABRT_SESS_RECOV)
462                 return;
463         WARN_ON_ONCE(task->state == ISCSI_TASK_FREE);
464         task->state = state;
465
466         if (!list_empty(&task->running))
467                 list_del_init(&task->running);
468
469         if (conn->task == task)
470                 conn->task = NULL;
471
472         if (conn->ping_task == task)
473                 conn->ping_task = NULL;
474
475         /* release get from queueing */
476         __iscsi_put_task(task);
477 }
478
479 /*
480  * session lock must be held and if not called for a task that is
481  * still pending or from the xmit thread, then xmit thread must
482  * be suspended.
483  */
484 static void fail_scsi_task(struct iscsi_task *task, int err)
485 {
486         struct iscsi_conn *conn = task->conn;
487         struct scsi_cmnd *sc;
488         int state;
489
490         /*
491          * if a command completes and we get a successful tmf response
492          * we will hit this because the scsi eh abort code does not take
493          * a ref to the task.
494          */
495         sc = task->sc;
496         if (!sc)
497                 return;
498
499         if (task->state == ISCSI_TASK_PENDING) {
500                 /*
501                  * cmd never made it to the xmit thread, so we should not count
502                  * the cmd in the sequencing
503                  */
504                 conn->session->queued_cmdsn--;
505                 /* it was never sent so just complete like normal */
506                 state = ISCSI_TASK_COMPLETED;
507         } else if (err == DID_TRANSPORT_DISRUPTED)
508                 state = ISCSI_TASK_ABRT_SESS_RECOV;
509         else
510                 state = ISCSI_TASK_ABRT_TMF;
511
512         sc->result = err << 16;
513         if (!scsi_bidi_cmnd(sc))
514                 scsi_set_resid(sc, scsi_bufflen(sc));
515         else {
516                 scsi_out(sc)->resid = scsi_out(sc)->length;
517                 scsi_in(sc)->resid = scsi_in(sc)->length;
518         }
519
520         iscsi_complete_task(task, state);
521 }
522
523 static int iscsi_prep_mgmt_task(struct iscsi_conn *conn,
524                                 struct iscsi_task *task)
525 {
526         struct iscsi_session *session = conn->session;
527         struct iscsi_hdr *hdr = task->hdr;
528         struct iscsi_nopout *nop = (struct iscsi_nopout *)hdr;
529
530         if (conn->session->state == ISCSI_STATE_LOGGING_OUT)
531                 return -ENOTCONN;
532
533         if (hdr->opcode != (ISCSI_OP_LOGIN | ISCSI_OP_IMMEDIATE) &&
534             hdr->opcode != (ISCSI_OP_TEXT | ISCSI_OP_IMMEDIATE))
535                 nop->exp_statsn = cpu_to_be32(conn->exp_statsn);
536         /*
537          * pre-format CmdSN for outgoing PDU.
538          */
539         nop->cmdsn = cpu_to_be32(session->cmdsn);
540         if (hdr->itt != RESERVED_ITT) {
541                 /*
542                  * TODO: We always use immediate, so we never hit this.
543                  * If we start to send tmfs or nops as non-immediate then
544                  * we should start checking the cmdsn numbers for mgmt tasks.
545                  */
546                 if (conn->c_stage == ISCSI_CONN_STARTED &&
547                     !(hdr->opcode & ISCSI_OP_IMMEDIATE)) {
548                         session->queued_cmdsn++;
549                         session->cmdsn++;
550                 }
551         }
552
553         if (session->tt->init_task && session->tt->init_task(task))
554                 return -EIO;
555
556         if ((hdr->opcode & ISCSI_OPCODE_MASK) == ISCSI_OP_LOGOUT)
557                 session->state = ISCSI_STATE_LOGGING_OUT;
558
559         task->state = ISCSI_TASK_RUNNING;
560         ISCSI_DBG_SESSION(session, "mgmtpdu [op 0x%x hdr->itt 0x%x "
561                           "datalen %d]\n", hdr->opcode & ISCSI_OPCODE_MASK,
562                           hdr->itt, task->data_count);
563         return 0;
564 }
565
566 static struct iscsi_task *
567 __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
568                       char *data, uint32_t data_size)
569 {
570         struct iscsi_session *session = conn->session;
571         struct iscsi_host *ihost = shost_priv(session->host);
572         struct iscsi_task *task;
573         itt_t itt;
574
575         if (session->state == ISCSI_STATE_TERMINATE)
576                 return NULL;
577
578         if (hdr->opcode == (ISCSI_OP_LOGIN | ISCSI_OP_IMMEDIATE) ||
579             hdr->opcode == (ISCSI_OP_TEXT | ISCSI_OP_IMMEDIATE))
580                 /*
581                  * Login and Text are sent serially, in
582                  * request-followed-by-response sequence.
583                  * Same task can be used. Same ITT must be used.
584                  * Note that login_task is preallocated at conn_create().
585                  */
586                 task = conn->login_task;
587         else {
588                 if (session->state != ISCSI_STATE_LOGGED_IN)
589                         return NULL;
590
591                 BUG_ON(conn->c_stage == ISCSI_CONN_INITIAL_STAGE);
592                 BUG_ON(conn->c_stage == ISCSI_CONN_STOPPED);
593
594                 if (!__kfifo_get(session->cmdpool.queue,
595                                  (void*)&task, sizeof(void*)))
596                         return NULL;
597         }
598         /*
599          * released in complete pdu for task we expect a response for, and
600          * released by the lld when it has transmitted the task for
601          * pdus we do not expect a response for.
602          */
603         atomic_set(&task->refcount, 1);
604         task->conn = conn;
605         task->sc = NULL;
606         INIT_LIST_HEAD(&task->running);
607         task->state = ISCSI_TASK_PENDING;
608
609         if (data_size) {
610                 memcpy(task->data, data, data_size);
611                 task->data_count = data_size;
612         } else
613                 task->data_count = 0;
614
615         if (conn->session->tt->alloc_pdu) {
616                 if (conn->session->tt->alloc_pdu(task, hdr->opcode)) {
617                         iscsi_conn_printk(KERN_ERR, conn, "Could not allocate "
618                                          "pdu for mgmt task.\n");
619                         goto free_task;
620                 }
621         }
622
623         itt = task->hdr->itt;
624         task->hdr_len = sizeof(struct iscsi_hdr);
625         memcpy(task->hdr, hdr, sizeof(struct iscsi_hdr));
626
627         if (hdr->itt != RESERVED_ITT) {
628                 if (session->tt->parse_pdu_itt)
629                         task->hdr->itt = itt;
630                 else
631                         task->hdr->itt = build_itt(task->itt,
632                                                    task->conn->session->age);
633         }
634
635         if (!ihost->workq) {
636                 if (iscsi_prep_mgmt_task(conn, task))
637                         goto free_task;
638
639                 if (session->tt->xmit_task(task))
640                         goto free_task;
641         } else {
642                 list_add_tail(&task->running, &conn->mgmtqueue);
643                 iscsi_conn_queue_work(conn);
644         }
645
646         return task;
647
648 free_task:
649         __iscsi_put_task(task);
650         return NULL;
651 }
652
653 int iscsi_conn_send_pdu(struct iscsi_cls_conn *cls_conn, struct iscsi_hdr *hdr,
654                         char *data, uint32_t data_size)
655 {
656         struct iscsi_conn *conn = cls_conn->dd_data;
657         struct iscsi_session *session = conn->session;
658         int err = 0;
659
660         spin_lock_bh(&session->lock);
661         if (!__iscsi_conn_send_pdu(conn, hdr, data, data_size))
662                 err = -EPERM;
663         spin_unlock_bh(&session->lock);
664         return err;
665 }
666 EXPORT_SYMBOL_GPL(iscsi_conn_send_pdu);
667
668 /**
669  * iscsi_cmd_rsp - SCSI Command Response processing
670  * @conn: iscsi connection
671  * @hdr: iscsi header
672  * @task: scsi command task
673  * @data: cmd data buffer
674  * @datalen: len of buffer
675  *
676  * iscsi_cmd_rsp sets up the scsi_cmnd fields based on the PDU and
677  * then completes the command and task.
678  **/
679 static void iscsi_scsi_cmd_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
680                                struct iscsi_task *task, char *data,
681                                int datalen)
682 {
683         struct iscsi_cmd_rsp *rhdr = (struct iscsi_cmd_rsp *)hdr;
684         struct iscsi_session *session = conn->session;
685         struct scsi_cmnd *sc = task->sc;
686
687         iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
688         conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
689
690         sc->result = (DID_OK << 16) | rhdr->cmd_status;
691
692         if (rhdr->response != ISCSI_STATUS_CMD_COMPLETED) {
693                 sc->result = DID_ERROR << 16;
694                 goto out;
695         }
696
697         if (rhdr->cmd_status == SAM_STAT_CHECK_CONDITION) {
698                 uint16_t senselen;
699
700                 if (datalen < 2) {
701 invalid_datalen:
702                         iscsi_conn_printk(KERN_ERR,  conn,
703                                          "Got CHECK_CONDITION but invalid data "
704                                          "buffer size of %d\n", datalen);
705                         sc->result = DID_BAD_TARGET << 16;
706                         goto out;
707                 }
708
709                 senselen = get_unaligned_be16(data);
710                 if (datalen < senselen)
711                         goto invalid_datalen;
712
713                 memcpy(sc->sense_buffer, data + 2,
714                        min_t(uint16_t, senselen, SCSI_SENSE_BUFFERSIZE));
715                 ISCSI_DBG_SESSION(session, "copied %d bytes of sense\n",
716                                   min_t(uint16_t, senselen,
717                                   SCSI_SENSE_BUFFERSIZE));
718         }
719
720         if (rhdr->flags & (ISCSI_FLAG_CMD_BIDI_UNDERFLOW |
721                            ISCSI_FLAG_CMD_BIDI_OVERFLOW)) {
722                 int res_count = be32_to_cpu(rhdr->bi_residual_count);
723
724                 if (scsi_bidi_cmnd(sc) && res_count > 0 &&
725                                 (rhdr->flags & ISCSI_FLAG_CMD_BIDI_OVERFLOW ||
726                                  res_count <= scsi_in(sc)->length))
727                         scsi_in(sc)->resid = res_count;
728                 else
729                         sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
730         }
731
732         if (rhdr->flags & (ISCSI_FLAG_CMD_UNDERFLOW |
733                            ISCSI_FLAG_CMD_OVERFLOW)) {
734                 int res_count = be32_to_cpu(rhdr->residual_count);
735
736                 if (res_count > 0 &&
737                     (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
738                      res_count <= scsi_bufflen(sc)))
739                         /* write side for bidi or uni-io set_resid */
740                         scsi_set_resid(sc, res_count);
741                 else
742                         sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
743         }
744 out:
745         ISCSI_DBG_SESSION(session, "cmd rsp done [sc %p res %d itt 0x%x]\n",
746                           sc, sc->result, task->itt);
747         conn->scsirsp_pdus_cnt++;
748         iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
749 }
750
751 /**
752  * iscsi_data_in_rsp - SCSI Data-In Response processing
753  * @conn: iscsi connection
754  * @hdr:  iscsi pdu
755  * @task: scsi command task
756  **/
757 static void
758 iscsi_data_in_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
759                   struct iscsi_task *task)
760 {
761         struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)hdr;
762         struct scsi_cmnd *sc = task->sc;
763
764         if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
765                 return;
766
767         iscsi_update_cmdsn(conn->session, (struct iscsi_nopin *)hdr);
768         sc->result = (DID_OK << 16) | rhdr->cmd_status;
769         conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
770         if (rhdr->flags & (ISCSI_FLAG_DATA_UNDERFLOW |
771                            ISCSI_FLAG_DATA_OVERFLOW)) {
772                 int res_count = be32_to_cpu(rhdr->residual_count);
773
774                 if (res_count > 0 &&
775                     (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
776                      res_count <= scsi_in(sc)->length))
777                         scsi_in(sc)->resid = res_count;
778                 else
779                         sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
780         }
781
782         ISCSI_DBG_SESSION(conn->session, "data in with status done "
783                           "[sc %p res %d itt 0x%x]\n",
784                           sc, sc->result, task->itt);
785         conn->scsirsp_pdus_cnt++;
786         iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
787 }
788
789 static void iscsi_tmf_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
790 {
791         struct iscsi_tm_rsp *tmf = (struct iscsi_tm_rsp *)hdr;
792
793         conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
794         conn->tmfrsp_pdus_cnt++;
795
796         if (conn->tmf_state != TMF_QUEUED)
797                 return;
798
799         if (tmf->response == ISCSI_TMF_RSP_COMPLETE)
800                 conn->tmf_state = TMF_SUCCESS;
801         else if (tmf->response == ISCSI_TMF_RSP_NO_TASK)
802                 conn->tmf_state = TMF_NOT_FOUND;
803         else
804                 conn->tmf_state = TMF_FAILED;
805         wake_up(&conn->ehwait);
806 }
807
808 static void iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
809 {
810         struct iscsi_nopout hdr;
811         struct iscsi_task *task;
812
813         if (!rhdr && conn->ping_task)
814                 return;
815
816         memset(&hdr, 0, sizeof(struct iscsi_nopout));
817         hdr.opcode = ISCSI_OP_NOOP_OUT | ISCSI_OP_IMMEDIATE;
818         hdr.flags = ISCSI_FLAG_CMD_FINAL;
819
820         if (rhdr) {
821                 memcpy(hdr.lun, rhdr->lun, 8);
822                 hdr.ttt = rhdr->ttt;
823                 hdr.itt = RESERVED_ITT;
824         } else
825                 hdr.ttt = RESERVED_ITT;
826
827         task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)&hdr, NULL, 0);
828         if (!task)
829                 iscsi_conn_printk(KERN_ERR, conn, "Could not send nopout\n");
830         else if (!rhdr) {
831                 /* only track our nops */
832                 conn->ping_task = task;
833                 conn->last_ping = jiffies;
834         }
835 }
836
837 static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
838                                char *data, int datalen)
839 {
840         struct iscsi_reject *reject = (struct iscsi_reject *)hdr;
841         struct iscsi_hdr rejected_pdu;
842
843         conn->exp_statsn = be32_to_cpu(reject->statsn) + 1;
844
845         if (reject->reason == ISCSI_REASON_DATA_DIGEST_ERROR) {
846                 if (ntoh24(reject->dlength) > datalen)
847                         return ISCSI_ERR_PROTO;
848
849                 if (ntoh24(reject->dlength) >= sizeof(struct iscsi_hdr)) {
850                         memcpy(&rejected_pdu, data, sizeof(struct iscsi_hdr));
851                         iscsi_conn_printk(KERN_ERR, conn,
852                                           "pdu (op 0x%x) rejected "
853                                           "due to DataDigest error.\n",
854                                           rejected_pdu.opcode);
855                 }
856         }
857         return 0;
858 }
859
860 /**
861  * iscsi_itt_to_task - look up task by itt
862  * @conn: iscsi connection
863  * @itt: itt
864  *
865  * This should be used for mgmt tasks like login and nops, or if
866  * the LDD's itt space does not include the session age.
867  *
868  * The session lock must be held.
869  */
870 struct iscsi_task *iscsi_itt_to_task(struct iscsi_conn *conn, itt_t itt)
871 {
872         struct iscsi_session *session = conn->session;
873         int i;
874
875         if (itt == RESERVED_ITT)
876                 return NULL;
877
878         if (session->tt->parse_pdu_itt)
879                 session->tt->parse_pdu_itt(conn, itt, &i, NULL);
880         else
881                 i = get_itt(itt);
882         if (i >= session->cmds_max)
883                 return NULL;
884
885         return session->cmds[i];
886 }
887 EXPORT_SYMBOL_GPL(iscsi_itt_to_task);
888
889 /**
890  * __iscsi_complete_pdu - complete pdu
891  * @conn: iscsi conn
892  * @hdr: iscsi header
893  * @data: data buffer
894  * @datalen: len of data buffer
895  *
896  * Completes pdu processing by freeing any resources allocated at
897  * queuecommand or send generic. session lock must be held and verify
898  * itt must have been called.
899  */
900 int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
901                          char *data, int datalen)
902 {
903         struct iscsi_session *session = conn->session;
904         int opcode = hdr->opcode & ISCSI_OPCODE_MASK, rc = 0;
905         struct iscsi_task *task;
906         uint32_t itt;
907
908         conn->last_recv = jiffies;
909         rc = iscsi_verify_itt(conn, hdr->itt);
910         if (rc)
911                 return rc;
912
913         if (hdr->itt != RESERVED_ITT)
914                 itt = get_itt(hdr->itt);
915         else
916                 itt = ~0U;
917
918         ISCSI_DBG_SESSION(session, "[op 0x%x cid %d itt 0x%x len %d]\n",
919                           opcode, conn->id, itt, datalen);
920
921         if (itt == ~0U) {
922                 iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
923
924                 switch(opcode) {
925                 case ISCSI_OP_NOOP_IN:
926                         if (datalen) {
927                                 rc = ISCSI_ERR_PROTO;
928                                 break;
929                         }
930
931                         if (hdr->ttt == cpu_to_be32(ISCSI_RESERVED_TAG))
932                                 break;
933
934                         iscsi_send_nopout(conn, (struct iscsi_nopin*)hdr);
935                         break;
936                 case ISCSI_OP_REJECT:
937                         rc = iscsi_handle_reject(conn, hdr, data, datalen);
938                         break;
939                 case ISCSI_OP_ASYNC_EVENT:
940                         conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
941                         if (iscsi_recv_pdu(conn->cls_conn, hdr, data, datalen))
942                                 rc = ISCSI_ERR_CONN_FAILED;
943                         break;
944                 default:
945                         rc = ISCSI_ERR_BAD_OPCODE;
946                         break;
947                 }
948                 goto out;
949         }
950
951         switch(opcode) {
952         case ISCSI_OP_SCSI_CMD_RSP:
953         case ISCSI_OP_SCSI_DATA_IN:
954                 task = iscsi_itt_to_ctask(conn, hdr->itt);
955                 if (!task)
956                         return ISCSI_ERR_BAD_ITT;
957                 break;
958         case ISCSI_OP_R2T:
959                 /*
960                  * LLD handles R2Ts if they need to.
961                  */
962                 return 0;
963         case ISCSI_OP_LOGOUT_RSP:
964         case ISCSI_OP_LOGIN_RSP:
965         case ISCSI_OP_TEXT_RSP:
966         case ISCSI_OP_SCSI_TMFUNC_RSP:
967         case ISCSI_OP_NOOP_IN:
968                 task = iscsi_itt_to_task(conn, hdr->itt);
969                 if (!task)
970                         return ISCSI_ERR_BAD_ITT;
971                 break;
972         default:
973                 return ISCSI_ERR_BAD_OPCODE;
974         }
975
976         switch(opcode) {
977         case ISCSI_OP_SCSI_CMD_RSP:
978                 iscsi_scsi_cmd_rsp(conn, hdr, task, data, datalen);
979                 break;
980         case ISCSI_OP_SCSI_DATA_IN:
981                 iscsi_data_in_rsp(conn, hdr, task);
982                 break;
983         case ISCSI_OP_LOGOUT_RSP:
984                 iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
985                 if (datalen) {
986                         rc = ISCSI_ERR_PROTO;
987                         break;
988                 }
989                 conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
990                 goto recv_pdu;
991         case ISCSI_OP_LOGIN_RSP:
992         case ISCSI_OP_TEXT_RSP:
993                 iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
994                 /*
995                  * login related PDU's exp_statsn is handled in
996                  * userspace
997                  */
998                 goto recv_pdu;
999         case ISCSI_OP_SCSI_TMFUNC_RSP:
1000                 iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
1001                 if (datalen) {
1002                         rc = ISCSI_ERR_PROTO;
1003                         break;
1004                 }
1005
1006                 iscsi_tmf_rsp(conn, hdr);
1007                 iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
1008                 break;
1009         case ISCSI_OP_NOOP_IN:
1010                 iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
1011                 if (hdr->ttt != cpu_to_be32(ISCSI_RESERVED_TAG) || datalen) {
1012                         rc = ISCSI_ERR_PROTO;
1013                         break;
1014                 }
1015                 conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
1016
1017                 if (conn->ping_task != task)
1018                         /*
1019                          * If this is not in response to one of our
1020                          * nops then it must be from userspace.
1021                          */
1022                         goto recv_pdu;
1023
1024                 mod_timer(&conn->transport_timer, jiffies + conn->recv_timeout);
1025                 iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
1026                 break;
1027         default:
1028                 rc = ISCSI_ERR_BAD_OPCODE;
1029                 break;
1030         }
1031
1032 out:
1033         return rc;
1034 recv_pdu:
1035         if (iscsi_recv_pdu(conn->cls_conn, hdr, data, datalen))
1036                 rc = ISCSI_ERR_CONN_FAILED;
1037         iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
1038         return rc;
1039 }
1040 EXPORT_SYMBOL_GPL(__iscsi_complete_pdu);
1041
1042 int iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
1043                        char *data, int datalen)
1044 {
1045         int rc;
1046
1047         spin_lock(&conn->session->lock);
1048         rc = __iscsi_complete_pdu(conn, hdr, data, datalen);
1049         spin_unlock(&conn->session->lock);
1050         return rc;
1051 }
1052 EXPORT_SYMBOL_GPL(iscsi_complete_pdu);
1053
1054 int iscsi_verify_itt(struct iscsi_conn *conn, itt_t itt)
1055 {
1056         struct iscsi_session *session = conn->session;
1057         int age = 0, i = 0;
1058
1059         if (itt == RESERVED_ITT)
1060                 return 0;
1061
1062         if (session->tt->parse_pdu_itt)
1063                 session->tt->parse_pdu_itt(conn, itt, &i, &age);
1064         else {
1065                 i = get_itt(itt);
1066                 age = ((__force u32)itt >> ISCSI_AGE_SHIFT) & ISCSI_AGE_MASK;
1067         }
1068
1069         if (age != session->age) {
1070                 iscsi_conn_printk(KERN_ERR, conn,
1071                                   "received itt %x expected session age (%x)\n",
1072                                   (__force u32)itt, session->age);
1073                 return ISCSI_ERR_BAD_ITT;
1074         }
1075
1076         if (i >= session->cmds_max) {
1077                 iscsi_conn_printk(KERN_ERR, conn,
1078                                   "received invalid itt index %u (max cmds "
1079                                    "%u.\n", i, session->cmds_max);
1080                 return ISCSI_ERR_BAD_ITT;
1081         }
1082         return 0;
1083 }
1084 EXPORT_SYMBOL_GPL(iscsi_verify_itt);
1085
1086 /**
1087  * iscsi_itt_to_ctask - look up ctask by itt
1088  * @conn: iscsi connection
1089  * @itt: itt
1090  *
1091  * This should be used for cmd tasks.
1092  *
1093  * The session lock must be held.
1094  */
1095 struct iscsi_task *iscsi_itt_to_ctask(struct iscsi_conn *conn, itt_t itt)
1096 {
1097         struct iscsi_task *task;
1098
1099         if (iscsi_verify_itt(conn, itt))
1100                 return NULL;
1101
1102         task = iscsi_itt_to_task(conn, itt);
1103         if (!task || !task->sc)
1104                 return NULL;
1105
1106         if (task->sc->SCp.phase != conn->session->age) {
1107                 iscsi_session_printk(KERN_ERR, conn->session,
1108                                   "task's session age %d, expected %d\n",
1109                                   task->sc->SCp.phase, conn->session->age);
1110                 return NULL;
1111         }
1112
1113         return task;
1114 }
1115 EXPORT_SYMBOL_GPL(iscsi_itt_to_ctask);
1116
1117 void iscsi_session_failure(struct iscsi_session *session,
1118                            enum iscsi_err err)
1119 {
1120         struct iscsi_conn *conn;
1121         struct device *dev;
1122         unsigned long flags;
1123
1124         spin_lock_irqsave(&session->lock, flags);
1125         conn = session->leadconn;
1126         if (session->state == ISCSI_STATE_TERMINATE || !conn) {
1127                 spin_unlock_irqrestore(&session->lock, flags);
1128                 return;
1129         }
1130
1131         dev = get_device(&conn->cls_conn->dev);
1132         spin_unlock_irqrestore(&session->lock, flags);
1133         if (!dev)
1134                 return;
1135         /*
1136          * if the host is being removed bypass the connection
1137          * recovery initialization because we are going to kill
1138          * the session.
1139          */
1140         if (err == ISCSI_ERR_INVALID_HOST)
1141                 iscsi_conn_error_event(conn->cls_conn, err);
1142         else
1143                 iscsi_conn_failure(conn, err);
1144         put_device(dev);
1145 }
1146 EXPORT_SYMBOL_GPL(iscsi_session_failure);
1147
1148 void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
1149 {
1150         struct iscsi_session *session = conn->session;
1151         unsigned long flags;
1152
1153         spin_lock_irqsave(&session->lock, flags);
1154         if (session->state == ISCSI_STATE_FAILED) {
1155                 spin_unlock_irqrestore(&session->lock, flags);
1156                 return;
1157         }
1158
1159         if (conn->stop_stage == 0)
1160                 session->state = ISCSI_STATE_FAILED;
1161         spin_unlock_irqrestore(&session->lock, flags);
1162
1163         set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
1164         set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
1165         iscsi_conn_error_event(conn->cls_conn, err);
1166 }
1167 EXPORT_SYMBOL_GPL(iscsi_conn_failure);
1168
1169 static int iscsi_check_cmdsn_window_closed(struct iscsi_conn *conn)
1170 {
1171         struct iscsi_session *session = conn->session;
1172
1173         /*
1174          * Check for iSCSI window and take care of CmdSN wrap-around
1175          */
1176         if (!iscsi_sna_lte(session->queued_cmdsn, session->max_cmdsn)) {
1177                 ISCSI_DBG_SESSION(session, "iSCSI CmdSN closed. ExpCmdSn "
1178                                   "%u MaxCmdSN %u CmdSN %u/%u\n",
1179                                   session->exp_cmdsn, session->max_cmdsn,
1180                                   session->cmdsn, session->queued_cmdsn);
1181                 return -ENOSPC;
1182         }
1183         return 0;
1184 }
1185
1186 static int iscsi_xmit_task(struct iscsi_conn *conn)
1187 {
1188         struct iscsi_task *task = conn->task;
1189         int rc;
1190
1191         __iscsi_get_task(task);
1192         spin_unlock_bh(&conn->session->lock);
1193         rc = conn->session->tt->xmit_task(task);
1194         spin_lock_bh(&conn->session->lock);
1195         __iscsi_put_task(task);
1196         if (!rc)
1197                 /* done with this task */
1198                 conn->task = NULL;
1199         return rc;
1200 }
1201
1202 /**
1203  * iscsi_requeue_task - requeue task to run from session workqueue
1204  * @task: task to requeue
1205  *
1206  * LLDs that need to run a task from the session workqueue should call
1207  * this. The session lock must be held. This should only be called
1208  * by software drivers.
1209  */
1210 void iscsi_requeue_task(struct iscsi_task *task)
1211 {
1212         struct iscsi_conn *conn = task->conn;
1213
1214         /*
1215          * this may be on the requeue list already if the xmit_task callout
1216          * is handling the r2ts while we are adding new ones
1217          */
1218         if (list_empty(&task->running))
1219                 list_add_tail(&task->running, &conn->requeue);
1220         iscsi_conn_queue_work(conn);
1221 }
1222 EXPORT_SYMBOL_GPL(iscsi_requeue_task);
1223
1224 /**
1225  * iscsi_data_xmit - xmit any command into the scheduled connection
1226  * @conn: iscsi connection
1227  *
1228  * Notes:
1229  *      The function can return -EAGAIN in which case the caller must
1230  *      re-schedule it again later or recover. '0' return code means
1231  *      successful xmit.
1232  **/
1233 static int iscsi_data_xmit(struct iscsi_conn *conn)
1234 {
1235         int rc = 0;
1236
1237         spin_lock_bh(&conn->session->lock);
1238         if (unlikely(conn->suspend_tx)) {
1239                 ISCSI_DBG_SESSION(conn->session, "Tx suspended!\n");
1240                 spin_unlock_bh(&conn->session->lock);
1241                 return -ENODATA;
1242         }
1243
1244         if (conn->task) {
1245                 rc = iscsi_xmit_task(conn);
1246                 if (rc)
1247                         goto again;
1248         }
1249
1250         /*
1251          * process mgmt pdus like nops before commands since we should
1252          * only have one nop-out as a ping from us and targets should not
1253          * overflow us with nop-ins
1254          */
1255 check_mgmt:
1256         while (!list_empty(&conn->mgmtqueue)) {
1257                 conn->task = list_entry(conn->mgmtqueue.next,
1258                                          struct iscsi_task, running);
1259                 list_del_init(&conn->task->running);
1260                 if (iscsi_prep_mgmt_task(conn, conn->task)) {
1261                         __iscsi_put_task(conn->task);
1262                         conn->task = NULL;
1263                         continue;
1264                 }
1265                 rc = iscsi_xmit_task(conn);
1266                 if (rc)
1267                         goto again;
1268         }
1269
1270         /* process pending command queue */
1271         while (!list_empty(&conn->cmdqueue)) {
1272                 if (conn->tmf_state == TMF_QUEUED)
1273                         break;
1274
1275                 conn->task = list_entry(conn->cmdqueue.next,
1276                                          struct iscsi_task, running);
1277                 list_del_init(&conn->task->running);
1278                 if (conn->session->state == ISCSI_STATE_LOGGING_OUT) {
1279                         fail_scsi_task(conn->task, DID_IMM_RETRY);
1280                         continue;
1281                 }
1282                 rc = iscsi_prep_scsi_cmd_pdu(conn->task);
1283                 if (rc) {
1284                         if (rc == -ENOMEM) {
1285                                 list_add_tail(&conn->task->running,
1286                                               &conn->cmdqueue);
1287                                 conn->task = NULL;
1288                                 goto again;
1289                         } else
1290                                 fail_scsi_task(conn->task, DID_ABORT);
1291                         continue;
1292                 }
1293                 rc = iscsi_xmit_task(conn);
1294                 if (rc)
1295                         goto again;
1296                 /*
1297                  * we could continuously get new task requests so
1298                  * we need to check the mgmt queue for nops that need to
1299                  * be sent to aviod starvation
1300                  */
1301                 if (!list_empty(&conn->mgmtqueue))
1302                         goto check_mgmt;
1303         }
1304
1305         while (!list_empty(&conn->requeue)) {
1306                 if (conn->session->fast_abort && conn->tmf_state != TMF_INITIAL)
1307                         break;
1308
1309                 /*
1310                  * we always do fastlogout - conn stop code will clean up.
1311                  */
1312                 if (conn->session->state == ISCSI_STATE_LOGGING_OUT)
1313                         break;
1314
1315                 conn->task = list_entry(conn->requeue.next,
1316                                          struct iscsi_task, running);
1317                 list_del_init(&conn->task->running);
1318                 conn->task->state = ISCSI_TASK_RUNNING;
1319                 rc = iscsi_xmit_task(conn);
1320                 if (rc)
1321                         goto again;
1322                 if (!list_empty(&conn->mgmtqueue))
1323                         goto check_mgmt;
1324         }
1325         spin_unlock_bh(&conn->session->lock);
1326         return -ENODATA;
1327
1328 again:
1329         if (unlikely(conn->suspend_tx))
1330                 rc = -ENODATA;
1331         spin_unlock_bh(&conn->session->lock);
1332         return rc;
1333 }
1334
1335 static void iscsi_xmitworker(struct work_struct *work)
1336 {
1337         struct iscsi_conn *conn =
1338                 container_of(work, struct iscsi_conn, xmitwork);
1339         int rc;
1340         /*
1341          * serialize Xmit worker on a per-connection basis.
1342          */
1343         do {
1344                 rc = iscsi_data_xmit(conn);
1345         } while (rc >= 0 || rc == -EAGAIN);
1346 }
1347
1348 static inline struct iscsi_task *iscsi_alloc_task(struct iscsi_conn *conn,
1349                                                   struct scsi_cmnd *sc)
1350 {
1351         struct iscsi_task *task;
1352
1353         if (!__kfifo_get(conn->session->cmdpool.queue,
1354                          (void *) &task, sizeof(void *)))
1355                 return NULL;
1356
1357         sc->SCp.phase = conn->session->age;
1358         sc->SCp.ptr = (char *) task;
1359
1360         atomic_set(&task->refcount, 1);
1361         task->state = ISCSI_TASK_PENDING;
1362         task->conn = conn;
1363         task->sc = sc;
1364         INIT_LIST_HEAD(&task->running);
1365         return task;
1366 }
1367
1368 enum {
1369         FAILURE_BAD_HOST = 1,
1370         FAILURE_SESSION_FAILED,
1371         FAILURE_SESSION_FREED,
1372         FAILURE_WINDOW_CLOSED,
1373         FAILURE_OOM,
1374         FAILURE_SESSION_TERMINATE,
1375         FAILURE_SESSION_IN_RECOVERY,
1376         FAILURE_SESSION_RECOVERY_TIMEOUT,
1377         FAILURE_SESSION_LOGGING_OUT,
1378         FAILURE_SESSION_NOT_READY,
1379 };
1380
1381 int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
1382 {
1383         struct iscsi_cls_session *cls_session;
1384         struct Scsi_Host *host;
1385         struct iscsi_host *ihost;
1386         int reason = 0;
1387         struct iscsi_session *session;
1388         struct iscsi_conn *conn;
1389         struct iscsi_task *task = NULL;
1390
1391         sc->scsi_done = done;
1392         sc->result = 0;
1393         sc->SCp.ptr = NULL;
1394
1395         host = sc->device->host;
1396         ihost = shost_priv(host);
1397         spin_unlock(host->host_lock);
1398
1399         cls_session = starget_to_session(scsi_target(sc->device));
1400         session = cls_session->dd_data;
1401         spin_lock(&session->lock);
1402
1403         reason = iscsi_session_chkready(cls_session);
1404         if (reason) {
1405                 sc->result = reason;
1406                 goto fault;
1407         }
1408
1409         if (session->state != ISCSI_STATE_LOGGED_IN) {
1410                 /*
1411                  * to handle the race between when we set the recovery state
1412                  * and block the session we requeue here (commands could
1413                  * be entering our queuecommand while a block is starting
1414                  * up because the block code is not locked)
1415                  */
1416                 switch (session->state) {
1417                 case ISCSI_STATE_FAILED:
1418                 case ISCSI_STATE_IN_RECOVERY:
1419                         reason = FAILURE_SESSION_IN_RECOVERY;
1420                         sc->result = DID_IMM_RETRY << 16;
1421                         break;
1422                 case ISCSI_STATE_LOGGING_OUT:
1423                         reason = FAILURE_SESSION_LOGGING_OUT;
1424                         sc->result = DID_IMM_RETRY << 16;
1425                         break;
1426                 case ISCSI_STATE_RECOVERY_FAILED:
1427                         reason = FAILURE_SESSION_RECOVERY_TIMEOUT;
1428                         sc->result = DID_TRANSPORT_FAILFAST << 16;
1429                         break;
1430                 case ISCSI_STATE_TERMINATE:
1431                         reason = FAILURE_SESSION_TERMINATE;
1432                         sc->result = DID_NO_CONNECT << 16;
1433                         break;
1434                 default:
1435                         reason = FAILURE_SESSION_FREED;
1436                         sc->result = DID_NO_CONNECT << 16;
1437                 }
1438                 goto fault;
1439         }
1440
1441         conn = session->leadconn;
1442         if (!conn) {
1443                 reason = FAILURE_SESSION_FREED;
1444                 sc->result = DID_NO_CONNECT << 16;
1445                 goto fault;
1446         }
1447
1448         if (iscsi_check_cmdsn_window_closed(conn)) {
1449                 reason = FAILURE_WINDOW_CLOSED;
1450                 goto reject;
1451         }
1452
1453         task = iscsi_alloc_task(conn, sc);
1454         if (!task) {
1455                 reason = FAILURE_OOM;
1456                 goto reject;
1457         }
1458
1459         if (!ihost->workq) {
1460                 reason = iscsi_prep_scsi_cmd_pdu(task);
1461                 if (reason) {
1462                         if (reason == -ENOMEM) {
1463                                 reason = FAILURE_OOM;
1464                                 goto prepd_reject;
1465                         } else {
1466                                 sc->result = DID_ABORT << 16;
1467                                 goto prepd_fault;
1468                         }
1469                 }
1470                 if (session->tt->xmit_task(task)) {
1471                         reason = FAILURE_SESSION_NOT_READY;
1472                         goto prepd_reject;
1473                 }
1474         } else {
1475                 list_add_tail(&task->running, &conn->cmdqueue);
1476                 iscsi_conn_queue_work(conn);
1477         }
1478
1479         session->queued_cmdsn++;
1480         spin_unlock(&session->lock);
1481         spin_lock(host->host_lock);
1482         return 0;
1483
1484 prepd_reject:
1485         sc->scsi_done = NULL;
1486         iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
1487 reject:
1488         spin_unlock(&session->lock);
1489         ISCSI_DBG_SESSION(session, "cmd 0x%x rejected (%d)\n",
1490                           sc->cmnd[0], reason);
1491         spin_lock(host->host_lock);
1492         return SCSI_MLQUEUE_TARGET_BUSY;
1493
1494 prepd_fault:
1495         sc->scsi_done = NULL;
1496         iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
1497 fault:
1498         spin_unlock(&session->lock);
1499         ISCSI_DBG_SESSION(session, "iscsi: cmd 0x%x is not queued (%d)\n",
1500                           sc->cmnd[0], reason);
1501         if (!scsi_bidi_cmnd(sc))
1502                 scsi_set_resid(sc, scsi_bufflen(sc));
1503         else {
1504                 scsi_out(sc)->resid = scsi_out(sc)->length;
1505                 scsi_in(sc)->resid = scsi_in(sc)->length;
1506         }
1507         done(sc);
1508         spin_lock(host->host_lock);
1509         return 0;
1510 }
1511 EXPORT_SYMBOL_GPL(iscsi_queuecommand);
1512
1513 int iscsi_change_queue_depth(struct scsi_device *sdev, int depth)
1514 {
1515         scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
1516         return sdev->queue_depth;
1517 }
1518 EXPORT_SYMBOL_GPL(iscsi_change_queue_depth);
1519
1520 int iscsi_target_alloc(struct scsi_target *starget)
1521 {
1522         struct iscsi_cls_session *cls_session = starget_to_session(starget);
1523         struct iscsi_session *session = cls_session->dd_data;
1524
1525         starget->can_queue = session->scsi_cmds_max;
1526         return 0;
1527 }
1528 EXPORT_SYMBOL_GPL(iscsi_target_alloc);
1529
1530 void iscsi_session_recovery_timedout(struct iscsi_cls_session *cls_session)
1531 {
1532         struct iscsi_session *session = cls_session->dd_data;
1533
1534         spin_lock_bh(&session->lock);
1535         if (session->state != ISCSI_STATE_LOGGED_IN) {
1536                 session->state = ISCSI_STATE_RECOVERY_FAILED;
1537                 if (session->leadconn)
1538                         wake_up(&session->leadconn->ehwait);
1539         }
1540         spin_unlock_bh(&session->lock);
1541 }
1542 EXPORT_SYMBOL_GPL(iscsi_session_recovery_timedout);
1543
1544 int iscsi_eh_target_reset(struct scsi_cmnd *sc)
1545 {
1546         struct iscsi_cls_session *cls_session;
1547         struct iscsi_session *session;
1548         struct iscsi_conn *conn;
1549
1550         cls_session = starget_to_session(scsi_target(sc->device));
1551         session = cls_session->dd_data;
1552         conn = session->leadconn;
1553
1554         mutex_lock(&session->eh_mutex);
1555         spin_lock_bh(&session->lock);
1556         if (session->state == ISCSI_STATE_TERMINATE) {
1557 failed:
1558                 iscsi_session_printk(KERN_INFO, session,
1559                                      "failing target reset: Could not log "
1560                                      "back into target [age %d]\n",
1561                                      session->age);
1562                 spin_unlock_bh(&session->lock);
1563                 mutex_unlock(&session->eh_mutex);
1564                 return FAILED;
1565         }
1566
1567         spin_unlock_bh(&session->lock);
1568         mutex_unlock(&session->eh_mutex);
1569         /*
1570          * we drop the lock here but the leadconn cannot be destoyed while
1571          * we are in the scsi eh
1572          */
1573         iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
1574
1575         ISCSI_DBG_SESSION(session, "wait for relogin\n");
1576         wait_event_interruptible(conn->ehwait,
1577                                  session->state == ISCSI_STATE_TERMINATE ||
1578                                  session->state == ISCSI_STATE_LOGGED_IN ||
1579                                  session->state == ISCSI_STATE_RECOVERY_FAILED);
1580         if (signal_pending(current))
1581                 flush_signals(current);
1582
1583         mutex_lock(&session->eh_mutex);
1584         spin_lock_bh(&session->lock);
1585         if (session->state == ISCSI_STATE_LOGGED_IN)
1586                 iscsi_session_printk(KERN_INFO, session,
1587                                      "target reset succeeded\n");
1588         else
1589                 goto failed;
1590         spin_unlock_bh(&session->lock);
1591         mutex_unlock(&session->eh_mutex);
1592         return SUCCESS;
1593 }
1594 EXPORT_SYMBOL_GPL(iscsi_eh_target_reset);
1595
1596 static void iscsi_tmf_timedout(unsigned long data)
1597 {
1598         struct iscsi_conn *conn = (struct iscsi_conn *)data;
1599         struct iscsi_session *session = conn->session;
1600
1601         spin_lock(&session->lock);
1602         if (conn->tmf_state == TMF_QUEUED) {
1603                 conn->tmf_state = TMF_TIMEDOUT;
1604                 ISCSI_DBG_SESSION(session, "tmf timedout\n");
1605                 /* unblock eh_abort() */
1606                 wake_up(&conn->ehwait);
1607         }
1608         spin_unlock(&session->lock);
1609 }
1610
1611 static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
1612                                    struct iscsi_tm *hdr, int age,
1613                                    int timeout)
1614 {
1615         struct iscsi_session *session = conn->session;
1616         struct iscsi_task *task;
1617
1618         task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)hdr,
1619                                       NULL, 0);
1620         if (!task) {
1621                 spin_unlock_bh(&session->lock);
1622                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
1623                 spin_lock_bh(&session->lock);
1624                 ISCSI_DBG_SESSION(session, "tmf exec failure\n");
1625                 return -EPERM;
1626         }
1627         conn->tmfcmd_pdus_cnt++;
1628         conn->tmf_timer.expires = timeout * HZ + jiffies;
1629         conn->tmf_timer.function = iscsi_tmf_timedout;
1630         conn->tmf_timer.data = (unsigned long)conn;
1631         add_timer(&conn->tmf_timer);
1632         ISCSI_DBG_SESSION(session, "tmf set timeout\n");
1633
1634         spin_unlock_bh(&session->lock);
1635         mutex_unlock(&session->eh_mutex);
1636
1637         /*
1638          * block eh thread until:
1639          *
1640          * 1) tmf response
1641          * 2) tmf timeout
1642          * 3) session is terminated or restarted or userspace has
1643          * given up on recovery
1644          */
1645         wait_event_interruptible(conn->ehwait, age != session->age ||
1646                                  session->state != ISCSI_STATE_LOGGED_IN ||
1647                                  conn->tmf_state != TMF_QUEUED);
1648         if (signal_pending(current))
1649                 flush_signals(current);
1650         del_timer_sync(&conn->tmf_timer);
1651
1652         mutex_lock(&session->eh_mutex);
1653         spin_lock_bh(&session->lock);
1654         /* if the session drops it will clean up the task */
1655         if (age != session->age ||
1656             session->state != ISCSI_STATE_LOGGED_IN)
1657                 return -ENOTCONN;
1658         return 0;
1659 }
1660
1661 /*
1662  * Fail commands. session lock held and recv side suspended and xmit
1663  * thread flushed
1664  */
1665 static void fail_scsi_tasks(struct iscsi_conn *conn, unsigned lun,
1666                             int error)
1667 {
1668         struct iscsi_task *task;
1669         int i;
1670
1671         for (i = 0; i < conn->session->cmds_max; i++) {
1672                 task = conn->session->cmds[i];
1673                 if (!task->sc || task->state == ISCSI_TASK_FREE)
1674                         continue;
1675
1676                 if (lun != -1 && lun != task->sc->device->lun)
1677                         continue;
1678
1679                 ISCSI_DBG_SESSION(conn->session,
1680                                   "failing sc %p itt 0x%x state %d\n",
1681                                   task->sc, task->itt, task->state);
1682                 fail_scsi_task(task, error);
1683         }
1684 }
1685
1686 void iscsi_suspend_tx(struct iscsi_conn *conn)
1687 {
1688         struct Scsi_Host *shost = conn->session->host;
1689         struct iscsi_host *ihost = shost_priv(shost);
1690
1691         set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
1692         if (ihost->workq)
1693                 flush_workqueue(ihost->workq);
1694 }
1695 EXPORT_SYMBOL_GPL(iscsi_suspend_tx);
1696
1697 static void iscsi_start_tx(struct iscsi_conn *conn)
1698 {
1699         clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
1700         iscsi_conn_queue_work(conn);
1701 }
1702
1703 /*
1704  * We want to make sure a ping is in flight. It has timed out.
1705  * And we are not busy processing a pdu that is making
1706  * progress but got started before the ping and is taking a while
1707  * to complete so the ping is just stuck behind it in a queue.
1708  */
1709 static int iscsi_has_ping_timed_out(struct iscsi_conn *conn)
1710 {
1711         if (conn->ping_task &&
1712             time_before_eq(conn->last_recv + (conn->recv_timeout * HZ) +
1713                            (conn->ping_timeout * HZ), jiffies))
1714                 return 1;
1715         else
1716                 return 0;
1717 }
1718
1719 static enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *scmd)
1720 {
1721         struct iscsi_cls_session *cls_session;
1722         struct iscsi_session *session;
1723         struct iscsi_conn *conn;
1724         enum blk_eh_timer_return rc = BLK_EH_NOT_HANDLED;
1725
1726         cls_session = starget_to_session(scsi_target(scmd->device));
1727         session = cls_session->dd_data;
1728
1729         ISCSI_DBG_SESSION(session, "scsi cmd %p timedout\n", scmd);
1730
1731         spin_lock(&session->lock);
1732         if (session->state != ISCSI_STATE_LOGGED_IN) {
1733                 /*
1734                  * We are probably in the middle of iscsi recovery so let
1735                  * that complete and handle the error.
1736                  */
1737                 rc = BLK_EH_RESET_TIMER;
1738                 goto done;
1739         }
1740
1741         conn = session->leadconn;
1742         if (!conn) {
1743                 /* In the middle of shuting down */
1744                 rc = BLK_EH_RESET_TIMER;
1745                 goto done;
1746         }
1747
1748         if (!conn->recv_timeout && !conn->ping_timeout)
1749                 goto done;
1750         /*
1751          * if the ping timedout then we are in the middle of cleaning up
1752          * and can let the iscsi eh handle it
1753          */
1754         if (iscsi_has_ping_timed_out(conn)) {
1755                 rc = BLK_EH_RESET_TIMER;
1756                 goto done;
1757         }
1758         /*
1759          * if we are about to check the transport then give the command
1760          * more time
1761          */
1762         if (time_before_eq(conn->last_recv + (conn->recv_timeout * HZ),
1763                            jiffies)) {
1764                 rc = BLK_EH_RESET_TIMER;
1765                 goto done;
1766         }
1767
1768         /* if in the middle of checking the transport then give us more time */
1769         if (conn->ping_task)
1770                 rc = BLK_EH_RESET_TIMER;
1771 done:
1772         spin_unlock(&session->lock);
1773         ISCSI_DBG_SESSION(session, "return %s\n", rc == BLK_EH_RESET_TIMER ?
1774                           "timer reset" : "nh");
1775         return rc;
1776 }
1777
1778 static void iscsi_check_transport_timeouts(unsigned long data)
1779 {
1780         struct iscsi_conn *conn = (struct iscsi_conn *)data;
1781         struct iscsi_session *session = conn->session;
1782         unsigned long recv_timeout, next_timeout = 0, last_recv;
1783
1784         spin_lock(&session->lock);
1785         if (session->state != ISCSI_STATE_LOGGED_IN)
1786                 goto done;
1787
1788         recv_timeout = conn->recv_timeout;
1789         if (!recv_timeout)
1790                 goto done;
1791
1792         recv_timeout *= HZ;
1793         last_recv = conn->last_recv;
1794
1795         if (iscsi_has_ping_timed_out(conn)) {
1796                 iscsi_conn_printk(KERN_ERR, conn, "ping timeout of %d secs "
1797                                   "expired, recv timeout %d, last rx %lu, "
1798                                   "last ping %lu, now %lu\n",
1799                                   conn->ping_timeout, conn->recv_timeout,
1800                                   last_recv, conn->last_ping, jiffies);
1801                 spin_unlock(&session->lock);
1802                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
1803                 return;
1804         }
1805
1806         if (time_before_eq(last_recv + recv_timeout, jiffies)) {
1807                 /* send a ping to try to provoke some traffic */
1808                 ISCSI_DBG_CONN(conn, "Sending nopout as ping\n");
1809                 iscsi_send_nopout(conn, NULL);
1810                 next_timeout = conn->last_ping + (conn->ping_timeout * HZ);
1811         } else
1812                 next_timeout = last_recv + recv_timeout;
1813
1814         ISCSI_DBG_CONN(conn, "Setting next tmo %lu\n", next_timeout);
1815         mod_timer(&conn->transport_timer, next_timeout);
1816 done:
1817         spin_unlock(&session->lock);
1818 }
1819
1820 static void iscsi_prep_abort_task_pdu(struct iscsi_task *task,
1821                                       struct iscsi_tm *hdr)
1822 {
1823         memset(hdr, 0, sizeof(*hdr));
1824         hdr->opcode = ISCSI_OP_SCSI_TMFUNC | ISCSI_OP_IMMEDIATE;
1825         hdr->flags = ISCSI_TM_FUNC_ABORT_TASK & ISCSI_FLAG_TM_FUNC_MASK;
1826         hdr->flags |= ISCSI_FLAG_CMD_FINAL;
1827         memcpy(hdr->lun, task->lun, sizeof(hdr->lun));
1828         hdr->rtt = task->hdr_itt;
1829         hdr->refcmdsn = task->cmdsn;
1830 }
1831
1832 int iscsi_eh_abort(struct scsi_cmnd *sc)
1833 {
1834         struct iscsi_cls_session *cls_session;
1835         struct iscsi_session *session;
1836         struct iscsi_conn *conn;
1837         struct iscsi_task *task;
1838         struct iscsi_tm *hdr;
1839         int rc, age;
1840
1841         cls_session = starget_to_session(scsi_target(sc->device));
1842         session = cls_session->dd_data;
1843
1844         ISCSI_DBG_SESSION(session, "aborting sc %p\n", sc);
1845
1846         mutex_lock(&session->eh_mutex);
1847         spin_lock_bh(&session->lock);
1848         /*
1849          * if session was ISCSI_STATE_IN_RECOVERY then we may not have
1850          * got the command.
1851          */
1852         if (!sc->SCp.ptr) {
1853                 ISCSI_DBG_SESSION(session, "sc never reached iscsi layer or "
1854                                   "it completed.\n");
1855                 spin_unlock_bh(&session->lock);
1856                 mutex_unlock(&session->eh_mutex);
1857                 return SUCCESS;
1858         }
1859
1860         /*
1861          * If we are not logged in or we have started a new session
1862          * then let the host reset code handle this
1863          */
1864         if (!session->leadconn || session->state != ISCSI_STATE_LOGGED_IN ||
1865             sc->SCp.phase != session->age) {
1866                 spin_unlock_bh(&session->lock);
1867                 mutex_unlock(&session->eh_mutex);
1868                 ISCSI_DBG_SESSION(session, "failing abort due to dropped "
1869                                   "session.\n");
1870                 return FAILED;
1871         }
1872
1873         conn = session->leadconn;
1874         conn->eh_abort_cnt++;
1875         age = session->age;
1876
1877         task = (struct iscsi_task *)sc->SCp.ptr;
1878         ISCSI_DBG_SESSION(session, "aborting [sc %p itt 0x%x]\n",
1879                           sc, task->itt);
1880
1881         /* task completed before time out */
1882         if (!task->sc) {
1883                 ISCSI_DBG_SESSION(session, "sc completed while abort in "
1884                                   "progress\n");
1885                 goto success;
1886         }
1887
1888         if (task->state == ISCSI_TASK_PENDING) {
1889                 fail_scsi_task(task, DID_ABORT);
1890                 goto success;
1891         }
1892
1893         /* only have one tmf outstanding at a time */
1894         if (conn->tmf_state != TMF_INITIAL)
1895                 goto failed;
1896         conn->tmf_state = TMF_QUEUED;
1897
1898         hdr = &conn->tmhdr;
1899         iscsi_prep_abort_task_pdu(task, hdr);
1900
1901         if (iscsi_exec_task_mgmt_fn(conn, hdr, age, session->abort_timeout)) {
1902                 rc = FAILED;
1903                 goto failed;
1904         }
1905
1906         switch (conn->tmf_state) {
1907         case TMF_SUCCESS:
1908                 spin_unlock_bh(&session->lock);
1909                 /*
1910                  * stop tx side incase the target had sent a abort rsp but
1911                  * the initiator was still writing out data.
1912                  */
1913                 iscsi_suspend_tx(conn);
1914                 /*
1915                  * we do not stop the recv side because targets have been
1916                  * good and have never sent us a successful tmf response
1917                  * then sent more data for the cmd.
1918                  */
1919                 spin_lock(&session->lock);
1920                 fail_scsi_task(task, DID_ABORT);
1921                 conn->tmf_state = TMF_INITIAL;
1922                 spin_unlock(&session->lock);
1923                 iscsi_start_tx(conn);
1924                 goto success_unlocked;
1925         case TMF_TIMEDOUT:
1926                 spin_unlock_bh(&session->lock);
1927                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
1928                 goto failed_unlocked;
1929         case TMF_NOT_FOUND:
1930                 if (!sc->SCp.ptr) {
1931                         conn->tmf_state = TMF_INITIAL;
1932                         /* task completed before tmf abort response */
1933                         ISCSI_DBG_SESSION(session, "sc completed while abort "
1934                                           "in progress\n");
1935                         goto success;
1936                 }
1937                 /* fall through */
1938         default:
1939                 conn->tmf_state = TMF_INITIAL;
1940                 goto failed;
1941         }
1942
1943 success:
1944         spin_unlock_bh(&session->lock);
1945 success_unlocked:
1946         ISCSI_DBG_SESSION(session, "abort success [sc %p itt 0x%x]\n",
1947                           sc, task->itt);
1948         mutex_unlock(&session->eh_mutex);
1949         return SUCCESS;
1950
1951 failed:
1952         spin_unlock_bh(&session->lock);
1953 failed_unlocked:
1954         ISCSI_DBG_SESSION(session, "abort failed [sc %p itt 0x%x]\n", sc,
1955                           task ? task->itt : 0);
1956         mutex_unlock(&session->eh_mutex);
1957         return FAILED;
1958 }
1959 EXPORT_SYMBOL_GPL(iscsi_eh_abort);
1960
1961 static void iscsi_prep_lun_reset_pdu(struct scsi_cmnd *sc, struct iscsi_tm *hdr)
1962 {
1963         memset(hdr, 0, sizeof(*hdr));
1964         hdr->opcode = ISCSI_OP_SCSI_TMFUNC | ISCSI_OP_IMMEDIATE;
1965         hdr->flags = ISCSI_TM_FUNC_LOGICAL_UNIT_RESET & ISCSI_FLAG_TM_FUNC_MASK;
1966         hdr->flags |= ISCSI_FLAG_CMD_FINAL;
1967         int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
1968         hdr->rtt = RESERVED_ITT;
1969 }
1970
1971 int iscsi_eh_device_reset(struct scsi_cmnd *sc)
1972 {
1973         struct iscsi_cls_session *cls_session;
1974         struct iscsi_session *session;
1975         struct iscsi_conn *conn;
1976         struct iscsi_tm *hdr;
1977         int rc = FAILED;
1978
1979         cls_session = starget_to_session(scsi_target(sc->device));
1980         session = cls_session->dd_data;
1981
1982         ISCSI_DBG_SESSION(session, "LU Reset [sc %p lun %u]\n",
1983                           sc, sc->device->lun);
1984
1985         mutex_lock(&session->eh_mutex);
1986         spin_lock_bh(&session->lock);
1987         /*
1988          * Just check if we are not logged in. We cannot check for
1989          * the phase because the reset could come from a ioctl.
1990          */
1991         if (!session->leadconn || session->state != ISCSI_STATE_LOGGED_IN)
1992                 goto unlock;
1993         conn = session->leadconn;
1994
1995         /* only have one tmf outstanding at a time */
1996         if (conn->tmf_state != TMF_INITIAL)
1997                 goto unlock;
1998         conn->tmf_state = TMF_QUEUED;
1999
2000         hdr = &conn->tmhdr;
2001         iscsi_prep_lun_reset_pdu(sc, hdr);
2002
2003         if (iscsi_exec_task_mgmt_fn(conn, hdr, session->age,
2004                                     session->lu_reset_timeout)) {
2005                 rc = FAILED;
2006                 goto unlock;
2007         }
2008
2009         switch (conn->tmf_state) {
2010         case TMF_SUCCESS:
2011                 break;
2012         case TMF_TIMEDOUT:
2013                 spin_unlock_bh(&session->lock);
2014                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
2015                 goto done;
2016         default:
2017                 conn->tmf_state = TMF_INITIAL;
2018                 goto unlock;
2019         }
2020
2021         rc = SUCCESS;
2022         spin_unlock_bh(&session->lock);
2023
2024         iscsi_suspend_tx(conn);
2025
2026         spin_lock_bh(&session->lock);
2027         fail_scsi_tasks(conn, sc->device->lun, DID_ERROR);
2028         conn->tmf_state = TMF_INITIAL;
2029         spin_unlock_bh(&session->lock);
2030
2031         iscsi_start_tx(conn);
2032         goto done;
2033
2034 unlock:
2035         spin_unlock_bh(&session->lock);
2036 done:
2037         ISCSI_DBG_SESSION(session, "dev reset result = %s\n",
2038                          rc == SUCCESS ? "SUCCESS" : "FAILED");
2039         mutex_unlock(&session->eh_mutex);
2040         return rc;
2041 }
2042 EXPORT_SYMBOL_GPL(iscsi_eh_device_reset);
2043
2044 /*
2045  * Pre-allocate a pool of @max items of @item_size. By default, the pool
2046  * should be accessed via kfifo_{get,put} on q->queue.
2047  * Optionally, the caller can obtain the array of object pointers
2048  * by passing in a non-NULL @items pointer
2049  */
2050 int
2051 iscsi_pool_init(struct iscsi_pool *q, int max, void ***items, int item_size)
2052 {
2053         int i, num_arrays = 1;
2054
2055         memset(q, 0, sizeof(*q));
2056
2057         q->max = max;
2058
2059         /* If the user passed an items pointer, he wants a copy of
2060          * the array. */
2061         if (items)
2062                 num_arrays++;
2063         q->pool = kzalloc(num_arrays * max * sizeof(void*), GFP_KERNEL);
2064         if (q->pool == NULL)
2065                 return -ENOMEM;
2066
2067         q->queue = kfifo_init((void*)q->pool, max * sizeof(void*),
2068                               GFP_KERNEL, NULL);
2069         if (IS_ERR(q->queue)) {
2070                 q->queue = NULL;
2071                 goto enomem;
2072         }
2073
2074         for (i = 0; i < max; i++) {
2075                 q->pool[i] = kzalloc(item_size, GFP_KERNEL);
2076                 if (q->pool[i] == NULL) {
2077                         q->max = i;
2078                         goto enomem;
2079                 }
2080                 __kfifo_put(q->queue, (void*)&q->pool[i], sizeof(void*));
2081         }
2082
2083         if (items) {
2084                 *items = q->pool + max;
2085                 memcpy(*items, q->pool, max * sizeof(void *));
2086         }
2087
2088         return 0;
2089
2090 enomem:
2091         iscsi_pool_free(q);
2092         return -ENOMEM;
2093 }
2094 EXPORT_SYMBOL_GPL(iscsi_pool_init);
2095
2096 void iscsi_pool_free(struct iscsi_pool *q)
2097 {
2098         int i;
2099
2100         for (i = 0; i < q->max; i++)
2101                 kfree(q->pool[i]);
2102         kfree(q->pool);
2103         kfree(q->queue);
2104 }
2105 EXPORT_SYMBOL_GPL(iscsi_pool_free);
2106
2107 /**
2108  * iscsi_host_add - add host to system
2109  * @shost: scsi host
2110  * @pdev: parent device
2111  *
2112  * This should be called by partial offload and software iscsi drivers
2113  * to add a host to the system.
2114  */
2115 int iscsi_host_add(struct Scsi_Host *shost, struct device *pdev)
2116 {
2117         if (!shost->can_queue)
2118                 shost->can_queue = ISCSI_DEF_XMIT_CMDS_MAX;
2119
2120         if (!shost->cmd_per_lun)
2121                 shost->cmd_per_lun = ISCSI_DEF_CMD_PER_LUN;
2122
2123         if (!shost->transportt->eh_timed_out)
2124                 shost->transportt->eh_timed_out = iscsi_eh_cmd_timed_out;
2125         return scsi_add_host(shost, pdev);
2126 }
2127 EXPORT_SYMBOL_GPL(iscsi_host_add);
2128
2129 /**
2130  * iscsi_host_alloc - allocate a host and driver data
2131  * @sht: scsi host template
2132  * @dd_data_size: driver host data size
2133  * @xmit_can_sleep: bool indicating if LLD will queue IO from a work queue
2134  *
2135  * This should be called by partial offload and software iscsi drivers.
2136  * To access the driver specific memory use the iscsi_host_priv() macro.
2137  */
2138 struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,
2139                                    int dd_data_size, bool xmit_can_sleep)
2140 {
2141         struct Scsi_Host *shost;
2142         struct iscsi_host *ihost;
2143
2144         shost = scsi_host_alloc(sht, sizeof(struct iscsi_host) + dd_data_size);
2145         if (!shost)
2146                 return NULL;
2147         ihost = shost_priv(shost);
2148
2149         if (xmit_can_sleep) {
2150                 snprintf(ihost->workq_name, sizeof(ihost->workq_name),
2151                         "iscsi_q_%d", shost->host_no);
2152                 ihost->workq = create_singlethread_workqueue(ihost->workq_name);
2153                 if (!ihost->workq)
2154                         goto free_host;
2155         }
2156
2157         spin_lock_init(&ihost->lock);
2158         ihost->state = ISCSI_HOST_SETUP;
2159         ihost->num_sessions = 0;
2160         init_waitqueue_head(&ihost->session_removal_wq);
2161         return shost;
2162
2163 free_host:
2164         scsi_host_put(shost);
2165         return NULL;
2166 }
2167 EXPORT_SYMBOL_GPL(iscsi_host_alloc);
2168
2169 static void iscsi_notify_host_removed(struct iscsi_cls_session *cls_session)
2170 {
2171         iscsi_session_failure(cls_session->dd_data, ISCSI_ERR_INVALID_HOST);
2172 }
2173
2174 /**
2175  * iscsi_host_remove - remove host and sessions
2176  * @shost: scsi host
2177  *
2178  * If there are any sessions left, this will initiate the removal and wait
2179  * for the completion.
2180  */
2181 void iscsi_host_remove(struct Scsi_Host *shost)
2182 {
2183         struct iscsi_host *ihost = shost_priv(shost);
2184         unsigned long flags;
2185
2186         spin_lock_irqsave(&ihost->lock, flags);
2187         ihost->state = ISCSI_HOST_REMOVED;
2188         spin_unlock_irqrestore(&ihost->lock, flags);
2189
2190         iscsi_host_for_each_session(shost, iscsi_notify_host_removed);
2191         wait_event_interruptible(ihost->session_removal_wq,
2192                                  ihost->num_sessions == 0);
2193         if (signal_pending(current))
2194                 flush_signals(current);
2195
2196         scsi_remove_host(shost);
2197         if (ihost->workq)
2198                 destroy_workqueue(ihost->workq);
2199 }
2200 EXPORT_SYMBOL_GPL(iscsi_host_remove);
2201
2202 void iscsi_host_free(struct Scsi_Host *shost)
2203 {
2204         struct iscsi_host *ihost = shost_priv(shost);
2205
2206         kfree(ihost->netdev);
2207         kfree(ihost->hwaddress);
2208         kfree(ihost->initiatorname);
2209         scsi_host_put(shost);
2210 }
2211 EXPORT_SYMBOL_GPL(iscsi_host_free);
2212
2213 static void iscsi_host_dec_session_cnt(struct Scsi_Host *shost)
2214 {
2215         struct iscsi_host *ihost = shost_priv(shost);
2216         unsigned long flags;
2217
2218         shost = scsi_host_get(shost);
2219         if (!shost) {
2220                 printk(KERN_ERR "Invalid state. Cannot notify host removal "
2221                       "of session teardown event because host already "
2222                       "removed.\n");
2223                 return;
2224         }
2225
2226         spin_lock_irqsave(&ihost->lock, flags);
2227         ihost->num_sessions--;
2228         if (ihost->num_sessions == 0)
2229                 wake_up(&ihost->session_removal_wq);
2230         spin_unlock_irqrestore(&ihost->lock, flags);
2231         scsi_host_put(shost);
2232 }
2233
2234 /**
2235  * iscsi_session_setup - create iscsi cls session and host and session
2236  * @iscsit: iscsi transport template
2237  * @shost: scsi host
2238  * @cmds_max: session can queue
2239  * @cmd_task_size: LLD task private data size
2240  * @initial_cmdsn: initial CmdSN
2241  *
2242  * This can be used by software iscsi_transports that allocate
2243  * a session per scsi host.
2244  *
2245  * Callers should set cmds_max to the largest total numer (mgmt + scsi) of
2246  * tasks they support. The iscsi layer reserves ISCSI_MGMT_CMDS_MAX tasks
2247  * for nop handling and login/logout requests.
2248  */
2249 struct iscsi_cls_session *
2250 iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
2251                     uint16_t cmds_max, int cmd_task_size,
2252                     uint32_t initial_cmdsn, unsigned int id)
2253 {
2254         struct iscsi_host *ihost = shost_priv(shost);
2255         struct iscsi_session *session;
2256         struct iscsi_cls_session *cls_session;
2257         int cmd_i, scsi_cmds, total_cmds = cmds_max;
2258         unsigned long flags;
2259
2260         spin_lock_irqsave(&ihost->lock, flags);
2261         if (ihost->state == ISCSI_HOST_REMOVED) {
2262                 spin_unlock_irqrestore(&ihost->lock, flags);
2263                 return NULL;
2264         }
2265         ihost->num_sessions++;
2266         spin_unlock_irqrestore(&ihost->lock, flags);
2267
2268         if (!total_cmds)
2269                 total_cmds = ISCSI_DEF_XMIT_CMDS_MAX;
2270         /*
2271          * The iscsi layer needs some tasks for nop handling and tmfs,
2272          * so the cmds_max must at least be greater than ISCSI_MGMT_CMDS_MAX
2273          * + 1 command for scsi IO.
2274          */
2275         if (total_cmds < ISCSI_TOTAL_CMDS_MIN) {
2276                 printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
2277                        "must be a power of two that is at least %d.\n",
2278                        total_cmds, ISCSI_TOTAL_CMDS_MIN);
2279                 goto dec_session_count;
2280         }
2281
2282         if (total_cmds > ISCSI_TOTAL_CMDS_MAX) {
2283                 printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
2284                        "must be a power of 2 less than or equal to %d.\n",
2285                        cmds_max, ISCSI_TOTAL_CMDS_MAX);
2286                 total_cmds = ISCSI_TOTAL_CMDS_MAX;
2287         }
2288
2289         if (!is_power_of_2(total_cmds)) {
2290                 printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
2291                        "must be a power of 2.\n", total_cmds);
2292                 total_cmds = rounddown_pow_of_two(total_cmds);
2293                 if (total_cmds < ISCSI_TOTAL_CMDS_MIN)
2294                         return NULL;
2295                 printk(KERN_INFO "iscsi: Rounding can_queue to %d.\n",
2296                        total_cmds);
2297         }
2298         scsi_cmds = total_cmds - ISCSI_MGMT_CMDS_MAX;
2299
2300         cls_session = iscsi_alloc_session(shost, iscsit,
2301                                           sizeof(struct iscsi_session));
2302         if (!cls_session)
2303                 goto dec_session_count;
2304         session = cls_session->dd_data;
2305         session->cls_session = cls_session;
2306         session->host = shost;
2307         session->state = ISCSI_STATE_FREE;
2308         session->fast_abort = 1;
2309         session->lu_reset_timeout = 15;
2310         session->abort_timeout = 10;
2311         session->scsi_cmds_max = scsi_cmds;
2312         session->cmds_max = total_cmds;
2313         session->queued_cmdsn = session->cmdsn = initial_cmdsn;
2314         session->exp_cmdsn = initial_cmdsn + 1;
2315         session->max_cmdsn = initial_cmdsn + 1;
2316         session->max_r2t = 1;
2317         session->tt = iscsit;
2318         mutex_init(&session->eh_mutex);
2319         spin_lock_init(&session->lock);
2320
2321         /* initialize SCSI PDU commands pool */
2322         if (iscsi_pool_init(&session->cmdpool, session->cmds_max,
2323                             (void***)&session->cmds,
2324                             cmd_task_size + sizeof(struct iscsi_task)))
2325                 goto cmdpool_alloc_fail;
2326
2327         /* pre-format cmds pool with ITT */
2328         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
2329                 struct iscsi_task *task = session->cmds[cmd_i];
2330
2331                 if (cmd_task_size)
2332                         task->dd_data = &task[1];
2333                 task->itt = cmd_i;
2334                 task->state = ISCSI_TASK_FREE;
2335                 INIT_LIST_HEAD(&task->running);
2336         }
2337
2338         if (!try_module_get(iscsit->owner))
2339                 goto module_get_fail;
2340
2341         if (iscsi_add_session(cls_session, id))
2342                 goto cls_session_fail;
2343
2344         return cls_session;
2345
2346 cls_session_fail:
2347         module_put(iscsit->owner);
2348 module_get_fail:
2349         iscsi_pool_free(&session->cmdpool);
2350 cmdpool_alloc_fail:
2351         iscsi_free_session(cls_session);
2352 dec_session_count:
2353         iscsi_host_dec_session_cnt(shost);
2354         return NULL;
2355 }
2356 EXPORT_SYMBOL_GPL(iscsi_session_setup);
2357
2358 /**
2359  * iscsi_session_teardown - destroy session, host, and cls_session
2360  * @cls_session: iscsi session
2361  *
2362  * The driver must have called iscsi_remove_session before
2363  * calling this.
2364  */
2365 void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
2366 {
2367         struct iscsi_session *session = cls_session->dd_data;
2368         struct module *owner = cls_session->transport->owner;
2369         struct Scsi_Host *shost = session->host;
2370
2371         iscsi_pool_free(&session->cmdpool);
2372
2373         kfree(session->password);
2374         kfree(session->password_in);
2375         kfree(session->username);
2376         kfree(session->username_in);
2377         kfree(session->targetname);
2378         kfree(session->initiatorname);
2379         kfree(session->ifacename);
2380
2381         iscsi_destroy_session(cls_session);
2382         iscsi_host_dec_session_cnt(shost);
2383         module_put(owner);
2384 }
2385 EXPORT_SYMBOL_GPL(iscsi_session_teardown);
2386
2387 /**
2388  * iscsi_conn_setup - create iscsi_cls_conn and iscsi_conn
2389  * @cls_session: iscsi_cls_session
2390  * @dd_size: private driver data size
2391  * @conn_idx: cid
2392  */
2393 struct iscsi_cls_conn *
2394 iscsi_conn_setup(struct iscsi_cls_session *cls_session, int dd_size,
2395                  uint32_t conn_idx)
2396 {
2397         struct iscsi_session *session = cls_session->dd_data;
2398         struct iscsi_conn *conn;
2399         struct iscsi_cls_conn *cls_conn;
2400         char *data;
2401
2402         cls_conn = iscsi_create_conn(cls_session, sizeof(*conn) + dd_size,
2403                                      conn_idx);
2404         if (!cls_conn)
2405                 return NULL;
2406         conn = cls_conn->dd_data;
2407         memset(conn, 0, sizeof(*conn) + dd_size);
2408
2409         conn->dd_data = cls_conn->dd_data + sizeof(*conn);
2410         conn->session = session;
2411         conn->cls_conn = cls_conn;
2412         conn->c_stage = ISCSI_CONN_INITIAL_STAGE;
2413         conn->id = conn_idx;
2414         conn->exp_statsn = 0;
2415         conn->tmf_state = TMF_INITIAL;
2416
2417         init_timer(&conn->transport_timer);
2418         conn->transport_timer.data = (unsigned long)conn;
2419         conn->transport_timer.function = iscsi_check_transport_timeouts;
2420
2421         INIT_LIST_HEAD(&conn->mgmtqueue);
2422         INIT_LIST_HEAD(&conn->cmdqueue);
2423         INIT_LIST_HEAD(&conn->requeue);
2424         INIT_WORK(&conn->xmitwork, iscsi_xmitworker);
2425
2426         /* allocate login_task used for the login/text sequences */
2427         spin_lock_bh(&session->lock);
2428         if (!__kfifo_get(session->cmdpool.queue,
2429                          (void*)&conn->login_task,
2430                          sizeof(void*))) {
2431                 spin_unlock_bh(&session->lock);
2432                 goto login_task_alloc_fail;
2433         }
2434         spin_unlock_bh(&session->lock);
2435
2436         data = (char *) __get_free_pages(GFP_KERNEL,
2437                                          get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
2438         if (!data)
2439                 goto login_task_data_alloc_fail;
2440         conn->login_task->data = conn->data = data;
2441
2442         init_timer(&conn->tmf_timer);
2443         init_waitqueue_head(&conn->ehwait);
2444
2445         return cls_conn;
2446
2447 login_task_data_alloc_fail:
2448         __kfifo_put(session->cmdpool.queue, (void*)&conn->login_task,
2449                     sizeof(void*));
2450 login_task_alloc_fail:
2451         iscsi_destroy_conn(cls_conn);
2452         return NULL;
2453 }
2454 EXPORT_SYMBOL_GPL(iscsi_conn_setup);
2455
2456 /**
2457  * iscsi_conn_teardown - teardown iscsi connection
2458  * cls_conn: iscsi class connection
2459  *
2460  * TODO: we may need to make this into a two step process
2461  * like scsi-mls remove + put host
2462  */
2463 void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
2464 {
2465         struct iscsi_conn *conn = cls_conn->dd_data;
2466         struct iscsi_session *session = conn->session;
2467         unsigned long flags;
2468
2469         del_timer_sync(&conn->transport_timer);
2470
2471         spin_lock_bh(&session->lock);
2472         conn->c_stage = ISCSI_CONN_CLEANUP_WAIT;
2473         if (session->leadconn == conn) {
2474                 /*
2475                  * leading connection? then give up on recovery.
2476                  */
2477                 session->state = ISCSI_STATE_TERMINATE;
2478                 wake_up(&conn->ehwait);
2479         }
2480         spin_unlock_bh(&session->lock);
2481
2482         /*
2483          * Block until all in-progress commands for this connection
2484          * time out or fail.
2485          */
2486         for (;;) {
2487                 spin_lock_irqsave(session->host->host_lock, flags);
2488                 if (!session->host->host_busy) { /* OK for ERL == 0 */
2489                         spin_unlock_irqrestore(session->host->host_lock, flags);
2490                         break;
2491                 }
2492                 spin_unlock_irqrestore(session->host->host_lock, flags);
2493                 msleep_interruptible(500);
2494                 iscsi_conn_printk(KERN_INFO, conn, "iscsi conn_destroy(): "
2495                                   "host_busy %d host_failed %d\n",
2496                                   session->host->host_busy,
2497                                   session->host->host_failed);
2498                 /*
2499                  * force eh_abort() to unblock
2500                  */
2501                 wake_up(&conn->ehwait);
2502         }
2503
2504         /* flush queued up work because we free the connection below */
2505         iscsi_suspend_tx(conn);
2506
2507         spin_lock_bh(&session->lock);
2508         free_pages((unsigned long) conn->data,
2509                    get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
2510         kfree(conn->persistent_address);
2511         __kfifo_put(session->cmdpool.queue, (void*)&conn->login_task,
2512                     sizeof(void*));
2513         if (session->leadconn == conn)
2514                 session->leadconn = NULL;
2515         spin_unlock_bh(&session->lock);
2516
2517         iscsi_destroy_conn(cls_conn);
2518 }
2519 EXPORT_SYMBOL_GPL(iscsi_conn_teardown);
2520
2521 int iscsi_conn_start(struct iscsi_cls_conn *cls_conn)
2522 {
2523         struct iscsi_conn *conn = cls_conn->dd_data;
2524         struct iscsi_session *session = conn->session;
2525
2526         if (!session) {
2527                 iscsi_conn_printk(KERN_ERR, conn,
2528                                   "can't start unbound connection\n");
2529                 return -EPERM;
2530         }
2531
2532         if ((session->imm_data_en || !session->initial_r2t_en) &&
2533              session->first_burst > session->max_burst) {
2534                 iscsi_conn_printk(KERN_INFO, conn, "invalid burst lengths: "
2535                                   "first_burst %d max_burst %d\n",
2536                                   session->first_burst, session->max_burst);
2537                 return -EINVAL;
2538         }
2539
2540         if (conn->ping_timeout && !conn->recv_timeout) {
2541                 iscsi_conn_printk(KERN_ERR, conn, "invalid recv timeout of "
2542                                   "zero. Using 5 seconds\n.");
2543                 conn->recv_timeout = 5;
2544         }
2545
2546         if (conn->recv_timeout && !conn->ping_timeout) {
2547                 iscsi_conn_printk(KERN_ERR, conn, "invalid ping timeout of "
2548                                   "zero. Using 5 seconds.\n");
2549                 conn->ping_timeout = 5;
2550         }
2551
2552         spin_lock_bh(&session->lock);
2553         conn->c_stage = ISCSI_CONN_STARTED;
2554         session->state = ISCSI_STATE_LOGGED_IN;
2555         session->queued_cmdsn = session->cmdsn;
2556
2557         conn->last_recv = jiffies;
2558         conn->last_ping = jiffies;
2559         if (conn->recv_timeout && conn->ping_timeout)
2560                 mod_timer(&conn->transport_timer,
2561                           jiffies + (conn->recv_timeout * HZ));
2562
2563         switch(conn->stop_stage) {
2564         case STOP_CONN_RECOVER:
2565                 /*
2566                  * unblock eh_abort() if it is blocked. re-try all
2567                  * commands after successful recovery
2568                  */
2569                 conn->stop_stage = 0;
2570                 conn->tmf_state = TMF_INITIAL;
2571                 session->age++;
2572                 if (session->age == 16)
2573                         session->age = 0;
2574                 break;
2575         case STOP_CONN_TERM:
2576                 conn->stop_stage = 0;
2577                 break;
2578         default:
2579                 break;
2580         }
2581         spin_unlock_bh(&session->lock);
2582
2583         iscsi_unblock_session(session->cls_session);
2584         wake_up(&conn->ehwait);
2585         return 0;
2586 }
2587 EXPORT_SYMBOL_GPL(iscsi_conn_start);
2588
2589 static void
2590 fail_mgmt_tasks(struct iscsi_session *session, struct iscsi_conn *conn)
2591 {
2592         struct iscsi_task *task;
2593         int i, state;
2594
2595         for (i = 0; i < conn->session->cmds_max; i++) {
2596                 task = conn->session->cmds[i];
2597                 if (task->sc)
2598                         continue;
2599
2600                 if (task->state == ISCSI_TASK_FREE)
2601                         continue;
2602
2603                 ISCSI_DBG_SESSION(conn->session,
2604                                   "failing mgmt itt 0x%x state %d\n",
2605                                   task->itt, task->state);
2606                 state = ISCSI_TASK_ABRT_SESS_RECOV;
2607                 if (task->state == ISCSI_TASK_PENDING)
2608                         state = ISCSI_TASK_COMPLETED;
2609                 iscsi_complete_task(task, state);
2610
2611         }
2612 }
2613
2614 static void iscsi_start_session_recovery(struct iscsi_session *session,
2615                                          struct iscsi_conn *conn, int flag)
2616 {
2617         int old_stop_stage;
2618
2619         mutex_lock(&session->eh_mutex);
2620         spin_lock_bh(&session->lock);
2621         if (conn->stop_stage == STOP_CONN_TERM) {
2622                 spin_unlock_bh(&session->lock);
2623                 mutex_unlock(&session->eh_mutex);
2624                 return;
2625         }
2626
2627         /*
2628          * When this is called for the in_login state, we only want to clean
2629          * up the login task and connection. We do not need to block and set
2630          * the recovery state again
2631          */
2632         if (flag == STOP_CONN_TERM)
2633                 session->state = ISCSI_STATE_TERMINATE;
2634         else if (conn->stop_stage != STOP_CONN_RECOVER)
2635                 session->state = ISCSI_STATE_IN_RECOVERY;
2636         spin_unlock_bh(&session->lock);
2637
2638         del_timer_sync(&conn->transport_timer);
2639         iscsi_suspend_tx(conn);
2640
2641         spin_lock_bh(&session->lock);
2642         old_stop_stage = conn->stop_stage;
2643         conn->stop_stage = flag;
2644         conn->c_stage = ISCSI_CONN_STOPPED;
2645         spin_unlock_bh(&session->lock);
2646
2647         /*
2648          * for connection level recovery we should not calculate
2649          * header digest. conn->hdr_size used for optimization
2650          * in hdr_extract() and will be re-negotiated at
2651          * set_param() time.
2652          */
2653         if (flag == STOP_CONN_RECOVER) {
2654                 conn->hdrdgst_en = 0;
2655                 conn->datadgst_en = 0;
2656                 if (session->state == ISCSI_STATE_IN_RECOVERY &&
2657                     old_stop_stage != STOP_CONN_RECOVER) {
2658                         ISCSI_DBG_SESSION(session, "blocking session\n");
2659                         iscsi_block_session(session->cls_session);
2660                 }
2661         }
2662
2663         /*
2664          * flush queues.
2665          */
2666         spin_lock_bh(&session->lock);
2667         fail_scsi_tasks(conn, -1, DID_TRANSPORT_DISRUPTED);
2668         fail_mgmt_tasks(session, conn);
2669         spin_unlock_bh(&session->lock);
2670         mutex_unlock(&session->eh_mutex);
2671 }
2672
2673 void iscsi_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
2674 {
2675         struct iscsi_conn *conn = cls_conn->dd_data;
2676         struct iscsi_session *session = conn->session;
2677
2678         switch (flag) {
2679         case STOP_CONN_RECOVER:
2680         case STOP_CONN_TERM:
2681                 iscsi_start_session_recovery(session, conn, flag);
2682                 break;
2683         default:
2684                 iscsi_conn_printk(KERN_ERR, conn,
2685                                   "invalid stop flag %d\n", flag);
2686         }
2687 }
2688 EXPORT_SYMBOL_GPL(iscsi_conn_stop);
2689
2690 int iscsi_conn_bind(struct iscsi_cls_session *cls_session,
2691                     struct iscsi_cls_conn *cls_conn, int is_leading)
2692 {
2693         struct iscsi_session *session = cls_session->dd_data;
2694         struct iscsi_conn *conn = cls_conn->dd_data;
2695
2696         spin_lock_bh(&session->lock);
2697         if (is_leading)
2698                 session->leadconn = conn;
2699         spin_unlock_bh(&session->lock);
2700
2701         /*
2702          * Unblock xmitworker(), Login Phase will pass through.
2703          */
2704         clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
2705         clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
2706         return 0;
2707 }
2708 EXPORT_SYMBOL_GPL(iscsi_conn_bind);
2709
2710 static int iscsi_switch_str_param(char **param, char *new_val_buf)
2711 {
2712         char *new_val;
2713
2714         if (*param) {
2715                 if (!strcmp(*param, new_val_buf))
2716                         return 0;
2717         }
2718
2719         new_val = kstrdup(new_val_buf, GFP_NOIO);
2720         if (!new_val)
2721                 return -ENOMEM;
2722
2723         kfree(*param);
2724         *param = new_val;
2725         return 0;
2726 }
2727
2728 int iscsi_set_param(struct iscsi_cls_conn *cls_conn,
2729                     enum iscsi_param param, char *buf, int buflen)
2730 {
2731         struct iscsi_conn *conn = cls_conn->dd_data;
2732         struct iscsi_session *session = conn->session;
2733         uint32_t value;
2734
2735         switch(param) {
2736         case ISCSI_PARAM_FAST_ABORT:
2737                 sscanf(buf, "%d", &session->fast_abort);
2738                 break;
2739         case ISCSI_PARAM_ABORT_TMO:
2740                 sscanf(buf, "%d", &session->abort_timeout);
2741                 break;
2742         case ISCSI_PARAM_LU_RESET_TMO:
2743                 sscanf(buf, "%d", &session->lu_reset_timeout);
2744                 break;
2745         case ISCSI_PARAM_PING_TMO:
2746                 sscanf(buf, "%d", &conn->ping_timeout);
2747                 break;
2748         case ISCSI_PARAM_RECV_TMO:
2749                 sscanf(buf, "%d", &conn->recv_timeout);
2750                 break;
2751         case ISCSI_PARAM_MAX_RECV_DLENGTH:
2752                 sscanf(buf, "%d", &conn->max_recv_dlength);
2753                 break;
2754         case ISCSI_PARAM_MAX_XMIT_DLENGTH:
2755                 sscanf(buf, "%d", &conn->max_xmit_dlength);
2756                 break;
2757         case ISCSI_PARAM_HDRDGST_EN:
2758                 sscanf(buf, "%d", &conn->hdrdgst_en);
2759                 break;
2760         case ISCSI_PARAM_DATADGST_EN:
2761                 sscanf(buf, "%d", &conn->datadgst_en);
2762                 break;
2763         case ISCSI_PARAM_INITIAL_R2T_EN:
2764                 sscanf(buf, "%d", &session->initial_r2t_en);
2765                 break;
2766         case ISCSI_PARAM_MAX_R2T:
2767                 sscanf(buf, "%d", &session->max_r2t);
2768                 break;
2769         case ISCSI_PARAM_IMM_DATA_EN:
2770                 sscanf(buf, "%d", &session->imm_data_en);
2771                 break;
2772         case ISCSI_PARAM_FIRST_BURST:
2773                 sscanf(buf, "%d", &session->first_burst);
2774                 break;
2775         case ISCSI_PARAM_MAX_BURST:
2776                 sscanf(buf, "%d", &session->max_burst);
2777                 break;
2778         case ISCSI_PARAM_PDU_INORDER_EN:
2779                 sscanf(buf, "%d", &session->pdu_inorder_en);
2780                 break;
2781         case ISCSI_PARAM_DATASEQ_INORDER_EN:
2782                 sscanf(buf, "%d", &session->dataseq_inorder_en);
2783                 break;
2784         case ISCSI_PARAM_ERL:
2785                 sscanf(buf, "%d", &session->erl);
2786                 break;
2787         case ISCSI_PARAM_IFMARKER_EN:
2788                 sscanf(buf, "%d", &value);
2789                 BUG_ON(value);
2790                 break;
2791         case ISCSI_PARAM_OFMARKER_EN:
2792                 sscanf(buf, "%d", &value);
2793                 BUG_ON(value);
2794                 break;
2795         case ISCSI_PARAM_EXP_STATSN:
2796                 sscanf(buf, "%u", &conn->exp_statsn);
2797                 break;
2798         case ISCSI_PARAM_USERNAME:
2799                 return iscsi_switch_str_param(&session->username, buf);
2800         case ISCSI_PARAM_USERNAME_IN:
2801                 return iscsi_switch_str_param(&session->username_in, buf);
2802         case ISCSI_PARAM_PASSWORD:
2803                 return iscsi_switch_str_param(&session->password, buf);
2804         case ISCSI_PARAM_PASSWORD_IN:
2805                 return iscsi_switch_str_param(&session->password_in, buf);
2806         case ISCSI_PARAM_TARGET_NAME:
2807                 return iscsi_switch_str_param(&session->targetname, buf);
2808         case ISCSI_PARAM_TPGT:
2809                 sscanf(buf, "%d", &session->tpgt);
2810                 break;
2811         case ISCSI_PARAM_PERSISTENT_PORT:
2812                 sscanf(buf, "%d", &conn->persistent_port);
2813                 break;
2814         case ISCSI_PARAM_PERSISTENT_ADDRESS:
2815                 return iscsi_switch_str_param(&conn->persistent_address, buf);
2816         case ISCSI_PARAM_IFACE_NAME:
2817                 return iscsi_switch_str_param(&session->ifacename, buf);
2818         case ISCSI_PARAM_INITIATOR_NAME:
2819                 return iscsi_switch_str_param(&session->initiatorname, buf);
2820         default:
2821                 return -ENOSYS;
2822         }
2823
2824         return 0;
2825 }
2826 EXPORT_SYMBOL_GPL(iscsi_set_param);
2827
2828 int iscsi_session_get_param(struct iscsi_cls_session *cls_session,
2829                             enum iscsi_param param, char *buf)
2830 {
2831         struct iscsi_session *session = cls_session->dd_data;
2832         int len;
2833
2834         switch(param) {
2835         case ISCSI_PARAM_FAST_ABORT:
2836                 len = sprintf(buf, "%d\n", session->fast_abort);
2837                 break;
2838         case ISCSI_PARAM_ABORT_TMO:
2839                 len = sprintf(buf, "%d\n", session->abort_timeout);
2840                 break;
2841         case ISCSI_PARAM_LU_RESET_TMO:
2842                 len = sprintf(buf, "%d\n", session->lu_reset_timeout);
2843                 break;
2844         case ISCSI_PARAM_INITIAL_R2T_EN:
2845                 len = sprintf(buf, "%d\n", session->initial_r2t_en);
2846                 break;
2847         case ISCSI_PARAM_MAX_R2T:
2848                 len = sprintf(buf, "%hu\n", session->max_r2t);
2849                 break;
2850         case ISCSI_PARAM_IMM_DATA_EN:
2851                 len = sprintf(buf, "%d\n", session->imm_data_en);
2852                 break;
2853         case ISCSI_PARAM_FIRST_BURST:
2854                 len = sprintf(buf, "%u\n", session->first_burst);
2855                 break;
2856         case ISCSI_PARAM_MAX_BURST:
2857                 len = sprintf(buf, "%u\n", session->max_burst);
2858                 break;
2859         case ISCSI_PARAM_PDU_INORDER_EN:
2860                 len = sprintf(buf, "%d\n", session->pdu_inorder_en);
2861                 break;
2862         case ISCSI_PARAM_DATASEQ_INORDER_EN:
2863                 len = sprintf(buf, "%d\n", session->dataseq_inorder_en);
2864                 break;
2865         case ISCSI_PARAM_ERL:
2866                 len = sprintf(buf, "%d\n", session->erl);
2867                 break;
2868         case ISCSI_PARAM_TARGET_NAME:
2869                 len = sprintf(buf, "%s\n", session->targetname);
2870                 break;
2871         case ISCSI_PARAM_TPGT:
2872                 len = sprintf(buf, "%d\n", session->tpgt);
2873                 break;
2874         case ISCSI_PARAM_USERNAME:
2875                 len = sprintf(buf, "%s\n", session->username);
2876                 break;
2877         case ISCSI_PARAM_USERNAME_IN:
2878                 len = sprintf(buf, "%s\n", session->username_in);
2879                 break;
2880         case ISCSI_PARAM_PASSWORD:
2881                 len = sprintf(buf, "%s\n", session->password);
2882                 break;
2883         case ISCSI_PARAM_PASSWORD_IN:
2884                 len = sprintf(buf, "%s\n", session->password_in);
2885                 break;
2886         case ISCSI_PARAM_IFACE_NAME:
2887                 len = sprintf(buf, "%s\n", session->ifacename);
2888                 break;
2889         case ISCSI_PARAM_INITIATOR_NAME:
2890                 len = sprintf(buf, "%s\n", session->initiatorname);
2891                 break;
2892         default:
2893                 return -ENOSYS;
2894         }
2895
2896         return len;
2897 }
2898 EXPORT_SYMBOL_GPL(iscsi_session_get_param);
2899
2900 int iscsi_conn_get_param(struct iscsi_cls_conn *cls_conn,
2901                          enum iscsi_param param, char *buf)
2902 {
2903         struct iscsi_conn *conn = cls_conn->dd_data;
2904         int len;
2905
2906         switch(param) {
2907         case ISCSI_PARAM_PING_TMO:
2908                 len = sprintf(buf, "%u\n", conn->ping_timeout);
2909                 break;
2910         case ISCSI_PARAM_RECV_TMO:
2911                 len = sprintf(buf, "%u\n", conn->recv_timeout);
2912                 break;
2913         case ISCSI_PARAM_MAX_RECV_DLENGTH:
2914                 len = sprintf(buf, "%u\n", conn->max_recv_dlength);
2915                 break;
2916         case ISCSI_PARAM_MAX_XMIT_DLENGTH:
2917                 len = sprintf(buf, "%u\n", conn->max_xmit_dlength);
2918                 break;
2919         case ISCSI_PARAM_HDRDGST_EN:
2920                 len = sprintf(buf, "%d\n", conn->hdrdgst_en);
2921                 break;
2922         case ISCSI_PARAM_DATADGST_EN:
2923                 len = sprintf(buf, "%d\n", conn->datadgst_en);
2924                 break;
2925         case ISCSI_PARAM_IFMARKER_EN:
2926                 len = sprintf(buf, "%d\n", conn->ifmarker_en);
2927                 break;
2928         case ISCSI_PARAM_OFMARKER_EN:
2929                 len = sprintf(buf, "%d\n", conn->ofmarker_en);
2930                 break;
2931         case ISCSI_PARAM_EXP_STATSN:
2932                 len = sprintf(buf, "%u\n", conn->exp_statsn);
2933                 break;
2934         case ISCSI_PARAM_PERSISTENT_PORT:
2935                 len = sprintf(buf, "%d\n", conn->persistent_port);
2936                 break;
2937         case ISCSI_PARAM_PERSISTENT_ADDRESS:
2938                 len = sprintf(buf, "%s\n", conn->persistent_address);
2939                 break;
2940         default:
2941                 return -ENOSYS;
2942         }
2943
2944         return len;
2945 }
2946 EXPORT_SYMBOL_GPL(iscsi_conn_get_param);
2947
2948 int iscsi_host_get_param(struct Scsi_Host *shost, enum iscsi_host_param param,
2949                          char *buf)
2950 {
2951         struct iscsi_host *ihost = shost_priv(shost);
2952         int len;
2953
2954         switch (param) {
2955         case ISCSI_HOST_PARAM_NETDEV_NAME:
2956                 len = sprintf(buf, "%s\n", ihost->netdev);
2957                 break;
2958         case ISCSI_HOST_PARAM_HWADDRESS:
2959                 len = sprintf(buf, "%s\n", ihost->hwaddress);
2960                 break;
2961         case ISCSI_HOST_PARAM_INITIATOR_NAME:
2962                 len = sprintf(buf, "%s\n", ihost->initiatorname);
2963                 break;
2964         case ISCSI_HOST_PARAM_IPADDRESS:
2965                 len = sprintf(buf, "%s\n", ihost->local_address);
2966                 break;
2967         default:
2968                 return -ENOSYS;
2969         }
2970
2971         return len;
2972 }
2973 EXPORT_SYMBOL_GPL(iscsi_host_get_param);
2974
2975 int iscsi_host_set_param(struct Scsi_Host *shost, enum iscsi_host_param param,
2976                          char *buf, int buflen)
2977 {
2978         struct iscsi_host *ihost = shost_priv(shost);
2979
2980         switch (param) {
2981         case ISCSI_HOST_PARAM_NETDEV_NAME:
2982                 return iscsi_switch_str_param(&ihost->netdev, buf);
2983         case ISCSI_HOST_PARAM_HWADDRESS:
2984                 return iscsi_switch_str_param(&ihost->hwaddress, buf);
2985         case ISCSI_HOST_PARAM_INITIATOR_NAME:
2986                 return iscsi_switch_str_param(&ihost->initiatorname, buf);
2987         default:
2988                 return -ENOSYS;
2989         }
2990
2991         return 0;
2992 }
2993 EXPORT_SYMBOL_GPL(iscsi_host_set_param);
2994
2995 MODULE_AUTHOR("Mike Christie");
2996 MODULE_DESCRIPTION("iSCSI library functions");
2997 MODULE_LICENSE("GPL");