[SCSI] libiscsi_tcp: replace tcp_debug/scsi_debug logging with session/conn logging
[linux-2.6.git] / drivers / scsi / libiscsi_tcp.c
1 /*
2  * iSCSI over TCP/IP Data-Path lib
3  *
4  * Copyright (C) 2004 Dmitry Yusupov
5  * Copyright (C) 2004 Alex Aizman
6  * Copyright (C) 2005 - 2006 Mike Christie
7  * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
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
12  * by 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, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18  * General Public License for more details.
19  *
20  * See the file COPYING included with this distribution for more details.
21  *
22  * Credits:
23  *      Christoph Hellwig
24  *      FUJITA Tomonori
25  *      Arne Redlich
26  *      Zhenyu Wang
27  */
28
29 #include <linux/types.h>
30 #include <linux/list.h>
31 #include <linux/inet.h>
32 #include <linux/file.h>
33 #include <linux/blkdev.h>
34 #include <linux/crypto.h>
35 #include <linux/delay.h>
36 #include <linux/kfifo.h>
37 #include <linux/scatterlist.h>
38 #include <net/tcp.h>
39 #include <scsi/scsi_cmnd.h>
40 #include <scsi/scsi_device.h>
41 #include <scsi/scsi_host.h>
42 #include <scsi/scsi.h>
43 #include <scsi/scsi_transport_iscsi.h>
44
45 #include "iscsi_tcp.h"
46
47 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
48               "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
49               "Alex Aizman <itn780@yahoo.com>");
50 MODULE_DESCRIPTION("iSCSI/TCP data-path");
51 MODULE_LICENSE("GPL");
52
53 static int iscsi_dbg_libtcp;
54 module_param_named(debug_libiscsi_tcp, iscsi_dbg_libtcp, int,
55                    S_IRUGO | S_IWUSR);
56 MODULE_PARM_DESC(debug_libiscsi_tcp, "Turn on debugging for libiscsi_tcp "
57                  "module. Set to 1 to turn on, and zero to turn off. Default "
58                  "is off.");
59
60 #define ISCSI_DBG_TCP(_conn, dbg_fmt, arg...)                   \
61         do {                                                    \
62                 if (iscsi_dbg_libtcp)                           \
63                         iscsi_conn_printk(KERN_INFO, _conn,     \
64                                              "%s " dbg_fmt,     \
65                                              __func__, ##arg);  \
66         } while (0);
67
68 static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
69                                    struct iscsi_segment *segment);
70
71 /*
72  * Scatterlist handling: inside the iscsi_segment, we
73  * remember an index into the scatterlist, and set data/size
74  * to the current scatterlist entry. For highmem pages, we
75  * kmap as needed.
76  *
77  * Note that the page is unmapped when we return from
78  * TCP's data_ready handler, so we may end up mapping and
79  * unmapping the same page repeatedly. The whole reason
80  * for this is that we shouldn't keep the page mapped
81  * outside the softirq.
82  */
83
84 /**
85  * iscsi_tcp_segment_init_sg - init indicated scatterlist entry
86  * @segment: the buffer object
87  * @sg: scatterlist
88  * @offset: byte offset into that sg entry
89  *
90  * This function sets up the segment so that subsequent
91  * data is copied to the indicated sg entry, at the given
92  * offset.
93  */
94 static inline void
95 iscsi_tcp_segment_init_sg(struct iscsi_segment *segment,
96                           struct scatterlist *sg, unsigned int offset)
97 {
98         segment->sg = sg;
99         segment->sg_offset = offset;
100         segment->size = min(sg->length - offset,
101                             segment->total_size - segment->total_copied);
102         segment->data = NULL;
103 }
104
105 /**
106  * iscsi_tcp_segment_map - map the current S/G page
107  * @segment: iscsi_segment
108  * @recv: 1 if called from recv path
109  *
110  * We only need to possibly kmap data if scatter lists are being used,
111  * because the iscsi passthrough and internal IO paths will never use high
112  * mem pages.
113  */
114 static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
115 {
116         struct scatterlist *sg;
117
118         if (segment->data != NULL || !segment->sg)
119                 return;
120
121         sg = segment->sg;
122         BUG_ON(segment->sg_mapped);
123         BUG_ON(sg->length == 0);
124
125         /*
126          * If the page count is greater than one it is ok to send
127          * to the network layer's zero copy send path. If not we
128          * have to go the slow sendmsg path. We always map for the
129          * recv path.
130          */
131         if (page_count(sg_page(sg)) >= 1 && !recv)
132                 return;
133
134         segment->sg_mapped = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
135         segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
136 }
137
138 void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
139 {
140         if (segment->sg_mapped) {
141                 kunmap_atomic(segment->sg_mapped, KM_SOFTIRQ0);
142                 segment->sg_mapped = NULL;
143                 segment->data = NULL;
144         }
145 }
146 EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap);
147
148 /*
149  * Splice the digest buffer into the buffer
150  */
151 static inline void
152 iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
153 {
154         segment->data = digest;
155         segment->digest_len = ISCSI_DIGEST_SIZE;
156         segment->total_size += ISCSI_DIGEST_SIZE;
157         segment->size = ISCSI_DIGEST_SIZE;
158         segment->copied = 0;
159         segment->sg = NULL;
160         segment->hash = NULL;
161 }
162
163 /**
164  * iscsi_tcp_segment_done - check whether the segment is complete
165  * @tcp_conn: iscsi tcp connection
166  * @segment: iscsi segment to check
167  * @recv: set to one of this is called from the recv path
168  * @copied: number of bytes copied
169  *
170  * Check if we're done receiving this segment. If the receive
171  * buffer is full but we expect more data, move on to the
172  * next entry in the scatterlist.
173  *
174  * If the amount of data we received isn't a multiple of 4,
175  * we will transparently receive the pad bytes, too.
176  *
177  * This function must be re-entrant.
178  */
179 int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
180                            struct iscsi_segment *segment, int recv,
181                            unsigned copied)
182 {
183         struct scatterlist sg;
184         unsigned int pad;
185
186         ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copied %u %u size %u %s\n",
187                       segment->copied, copied, segment->size,
188                       recv ? "recv" : "xmit");
189         if (segment->hash && copied) {
190                 /*
191                  * If a segment is kmapd we must unmap it before sending
192                  * to the crypto layer since that will try to kmap it again.
193                  */
194                 iscsi_tcp_segment_unmap(segment);
195
196                 if (!segment->data) {
197                         sg_init_table(&sg, 1);
198                         sg_set_page(&sg, sg_page(segment->sg), copied,
199                                     segment->copied + segment->sg_offset +
200                                                         segment->sg->offset);
201                 } else
202                         sg_init_one(&sg, segment->data + segment->copied,
203                                     copied);
204                 crypto_hash_update(segment->hash, &sg, copied);
205         }
206
207         segment->copied += copied;
208         if (segment->copied < segment->size) {
209                 iscsi_tcp_segment_map(segment, recv);
210                 return 0;
211         }
212
213         segment->total_copied += segment->copied;
214         segment->copied = 0;
215         segment->size = 0;
216
217         /* Unmap the current scatterlist page, if there is one. */
218         iscsi_tcp_segment_unmap(segment);
219
220         /* Do we have more scatterlist entries? */
221         ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "total copied %u total size %u\n",
222                       segment->total_copied, segment->total_size);
223         if (segment->total_copied < segment->total_size) {
224                 /* Proceed to the next entry in the scatterlist. */
225                 iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
226                                           0);
227                 iscsi_tcp_segment_map(segment, recv);
228                 BUG_ON(segment->size == 0);
229                 return 0;
230         }
231
232         /* Do we need to handle padding? */
233         if (!(tcp_conn->iscsi_conn->session->tt->caps & CAP_PADDING_OFFLOAD)) {
234                 pad = iscsi_padding(segment->total_copied);
235                 if (pad != 0) {
236                         ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
237                                       "consume %d pad bytes\n", pad);
238                         segment->total_size += pad;
239                         segment->size = pad;
240                         segment->data = segment->padbuf;
241                         return 0;
242                 }
243         }
244
245         /*
246          * Set us up for transferring the data digest. hdr digest
247          * is completely handled in hdr done function.
248          */
249         if (segment->hash) {
250                 crypto_hash_final(segment->hash, segment->digest);
251                 iscsi_tcp_segment_splice_digest(segment,
252                                  recv ? segment->recv_digest : segment->digest);
253                 return 0;
254         }
255
256         return 1;
257 }
258 EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
259
260 /**
261  * iscsi_tcp_segment_recv - copy data to segment
262  * @tcp_conn: the iSCSI TCP connection
263  * @segment: the buffer to copy to
264  * @ptr: data pointer
265  * @len: amount of data available
266  *
267  * This function copies up to @len bytes to the
268  * given buffer, and returns the number of bytes
269  * consumed, which can actually be less than @len.
270  *
271  * If hash digest is enabled, the function will update the
272  * hash while copying.
273  * Combining these two operations doesn't buy us a lot (yet),
274  * but in the future we could implement combined copy+crc,
275  * just way we do for network layer checksums.
276  */
277 static int
278 iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
279                        struct iscsi_segment *segment, const void *ptr,
280                        unsigned int len)
281 {
282         unsigned int copy = 0, copied = 0;
283
284         while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
285                 if (copied == len) {
286                         ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
287                                       "copied %d bytes\n", len);
288                         break;
289                 }
290
291                 copy = min(len - copied, segment->size - segment->copied);
292                 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
293                 memcpy(segment->data + segment->copied, ptr + copied, copy);
294                 copied += copy;
295         }
296         return copied;
297 }
298
299 inline void
300 iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, size_t hdrlen,
301                       unsigned char digest[ISCSI_DIGEST_SIZE])
302 {
303         struct scatterlist sg;
304
305         sg_init_one(&sg, hdr, hdrlen);
306         crypto_hash_digest(hash, &sg, hdrlen, digest);
307 }
308 EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
309
310 static inline int
311 iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
312                       struct iscsi_segment *segment)
313 {
314         if (!segment->digest_len)
315                 return 1;
316
317         if (memcmp(segment->recv_digest, segment->digest,
318                    segment->digest_len)) {
319                 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "digest mismatch\n");
320                 return 0;
321         }
322
323         return 1;
324 }
325
326 /*
327  * Helper function to set up segment buffer
328  */
329 static inline void
330 __iscsi_segment_init(struct iscsi_segment *segment, size_t size,
331                      iscsi_segment_done_fn_t *done, struct hash_desc *hash)
332 {
333         memset(segment, 0, sizeof(*segment));
334         segment->total_size = size;
335         segment->done = done;
336
337         if (hash) {
338                 segment->hash = hash;
339                 crypto_hash_init(hash);
340         }
341 }
342
343 inline void
344 iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
345                           size_t size, iscsi_segment_done_fn_t *done,
346                           struct hash_desc *hash)
347 {
348         __iscsi_segment_init(segment, size, done, hash);
349         segment->data = data;
350         segment->size = size;
351 }
352 EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
353
354 inline int
355 iscsi_segment_seek_sg(struct iscsi_segment *segment,
356                       struct scatterlist *sg_list, unsigned int sg_count,
357                       unsigned int offset, size_t size,
358                       iscsi_segment_done_fn_t *done, struct hash_desc *hash)
359 {
360         struct scatterlist *sg;
361         unsigned int i;
362
363         __iscsi_segment_init(segment, size, done, hash);
364         for_each_sg(sg_list, sg, sg_count, i) {
365                 if (offset < sg->length) {
366                         iscsi_tcp_segment_init_sg(segment, sg, offset);
367                         return 0;
368                 }
369                 offset -= sg->length;
370         }
371
372         return ISCSI_ERR_DATA_OFFSET;
373 }
374 EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
375
376 /**
377  * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
378  * @tcp_conn: iscsi connection to prep for
379  *
380  * This function always passes NULL for the hash argument, because when this
381  * function is called we do not yet know the final size of the header and want
382  * to delay the digest processing until we know that.
383  */
384 void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
385 {
386         ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
387                       "(%s)\n", tcp_conn->iscsi_conn->hdrdgst_en ?
388                       "digest enabled" : "digest disabled");
389         iscsi_segment_init_linear(&tcp_conn->in.segment,
390                                 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
391                                 iscsi_tcp_hdr_recv_done, NULL);
392 }
393 EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
394
395 /*
396  * Handle incoming reply to any other type of command
397  */
398 static int
399 iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
400                          struct iscsi_segment *segment)
401 {
402         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
403         int rc = 0;
404
405         if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
406                 return ISCSI_ERR_DATA_DGST;
407
408         rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
409                         conn->data, tcp_conn->in.datalen);
410         if (rc)
411                 return rc;
412
413         iscsi_tcp_hdr_recv_prep(tcp_conn);
414         return 0;
415 }
416
417 static void
418 iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
419 {
420         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
421         struct hash_desc *rx_hash = NULL;
422
423         if (conn->datadgst_en &
424             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
425                 rx_hash = tcp_conn->rx_hash;
426
427         iscsi_segment_init_linear(&tcp_conn->in.segment,
428                                 conn->data, tcp_conn->in.datalen,
429                                 iscsi_tcp_data_recv_done, rx_hash);
430 }
431
432 /**
433  * iscsi_tcp_cleanup_task - free tcp_task resources
434  * @task: iscsi task
435  *
436  * must be called with session lock
437  */
438 void iscsi_tcp_cleanup_task(struct iscsi_task *task)
439 {
440         struct iscsi_tcp_task *tcp_task = task->dd_data;
441         struct iscsi_r2t_info *r2t;
442
443         /* nothing to do for mgmt or pending tasks */
444         if (!task->sc || task->state == ISCSI_TASK_PENDING)
445                 return;
446
447         /* flush task's r2t queues */
448         while (__kfifo_get(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
449                 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
450                             sizeof(void*));
451                 ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
452         }
453
454         r2t = tcp_task->r2t;
455         if (r2t != NULL) {
456                 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
457                             sizeof(void*));
458                 tcp_task->r2t = NULL;
459         }
460 }
461 EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
462
463 /**
464  * iscsi_tcp_data_in - SCSI Data-In Response processing
465  * @conn: iscsi connection
466  * @task: scsi command task
467  */
468 static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
469 {
470         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
471         struct iscsi_tcp_task *tcp_task = task->dd_data;
472         struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
473         int datasn = be32_to_cpu(rhdr->datasn);
474         unsigned total_in_length = scsi_in(task->sc)->length;
475
476         iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
477         if (tcp_conn->in.datalen == 0)
478                 return 0;
479
480         if (tcp_task->exp_datasn != datasn) {
481                 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->datasn(%d)"
482                               "\n", tcp_task->exp_datasn, datasn);
483                 return ISCSI_ERR_DATASN;
484         }
485
486         tcp_task->exp_datasn++;
487
488         tcp_task->data_offset = be32_to_cpu(rhdr->offset);
489         if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
490                 ISCSI_DBG_TCP(conn, "data_offset(%d) + data_len(%d) > "
491                               "total_length_in(%d)\n", tcp_task->data_offset,
492                               tcp_conn->in.datalen, total_in_length);
493                 return ISCSI_ERR_DATA_OFFSET;
494         }
495
496         conn->datain_pdus_cnt++;
497         return 0;
498 }
499
500 /**
501  * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
502  * @conn: iscsi connection
503  * @task: scsi command task
504  */
505 static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
506 {
507         struct iscsi_session *session = conn->session;
508         struct iscsi_tcp_task *tcp_task = task->dd_data;
509         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
510         struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
511         struct iscsi_r2t_info *r2t;
512         int r2tsn = be32_to_cpu(rhdr->r2tsn);
513         int rc;
514
515         if (tcp_conn->in.datalen) {
516                 iscsi_conn_printk(KERN_ERR, conn,
517                                   "invalid R2t with datalen %d\n",
518                                   tcp_conn->in.datalen);
519                 return ISCSI_ERR_DATALEN;
520         }
521
522         if (tcp_task->exp_datasn != r2tsn){
523                 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
524                               tcp_task->exp_datasn, r2tsn);
525                 return ISCSI_ERR_R2TSN;
526         }
527
528         /* fill-in new R2T associated with the task */
529         iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
530
531         if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
532                 iscsi_conn_printk(KERN_INFO, conn,
533                                   "dropping R2T itt %d in recovery.\n",
534                                   task->itt);
535                 return 0;
536         }
537
538         rc = __kfifo_get(tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*));
539         if (!rc) {
540                 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
541                                   "Target has sent more R2Ts than it "
542                                   "negotiated for or driver has has leaked.\n");
543                 return ISCSI_ERR_PROTO;
544         }
545
546         r2t->exp_statsn = rhdr->statsn;
547         r2t->data_length = be32_to_cpu(rhdr->data_length);
548         if (r2t->data_length == 0) {
549                 iscsi_conn_printk(KERN_ERR, conn,
550                                   "invalid R2T with zero data len\n");
551                 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
552                             sizeof(void*));
553                 return ISCSI_ERR_DATALEN;
554         }
555
556         if (r2t->data_length > session->max_burst)
557                 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
558                               "burst %u. Attempting to execute request.\n",
559                               r2t->data_length, session->max_burst);
560
561         r2t->data_offset = be32_to_cpu(rhdr->data_offset);
562         if (r2t->data_offset + r2t->data_length > scsi_out(task->sc)->length) {
563                 iscsi_conn_printk(KERN_ERR, conn,
564                                   "invalid R2T with data len %u at offset %u "
565                                   "and total length %d\n", r2t->data_length,
566                                   r2t->data_offset, scsi_out(task->sc)->length);
567                 __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
568                             sizeof(void*));
569                 return ISCSI_ERR_DATALEN;
570         }
571
572         r2t->ttt = rhdr->ttt; /* no flip */
573         r2t->datasn = 0;
574         r2t->sent = 0;
575
576         tcp_task->exp_datasn = r2tsn + 1;
577         __kfifo_put(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
578         conn->r2t_pdus_cnt++;
579
580         iscsi_requeue_task(task);
581         return 0;
582 }
583
584 /*
585  * Handle incoming reply to DataIn command
586  */
587 static int
588 iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
589                           struct iscsi_segment *segment)
590 {
591         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
592         struct iscsi_hdr *hdr = tcp_conn->in.hdr;
593         int rc;
594
595         if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
596                 return ISCSI_ERR_DATA_DGST;
597
598         /* check for non-exceptional status */
599         if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
600                 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
601                 if (rc)
602                         return rc;
603         }
604
605         iscsi_tcp_hdr_recv_prep(tcp_conn);
606         return 0;
607 }
608
609 /**
610  * iscsi_tcp_hdr_dissect - process PDU header
611  * @conn: iSCSI connection
612  * @hdr: PDU header
613  *
614  * This function analyzes the header of the PDU received,
615  * and performs several sanity checks. If the PDU is accompanied
616  * by data, the receive buffer is set up to copy the incoming data
617  * to the correct location.
618  */
619 static int
620 iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
621 {
622         int rc = 0, opcode, ahslen;
623         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
624         struct iscsi_task *task;
625
626         /* verify PDU length */
627         tcp_conn->in.datalen = ntoh24(hdr->dlength);
628         if (tcp_conn->in.datalen > conn->max_recv_dlength) {
629                 iscsi_conn_printk(KERN_ERR, conn,
630                                   "iscsi_tcp: datalen %d > %d\n",
631                                   tcp_conn->in.datalen, conn->max_recv_dlength);
632                 return ISCSI_ERR_DATALEN;
633         }
634
635         /* Additional header segments. So far, we don't
636          * process additional headers.
637          */
638         ahslen = hdr->hlength << 2;
639
640         opcode = hdr->opcode & ISCSI_OPCODE_MASK;
641         /* verify itt (itt encoding: age+cid+itt) */
642         rc = iscsi_verify_itt(conn, hdr->itt);
643         if (rc)
644                 return rc;
645
646         ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
647                       opcode, ahslen, tcp_conn->in.datalen);
648
649         switch(opcode) {
650         case ISCSI_OP_SCSI_DATA_IN:
651                 spin_lock(&conn->session->lock);
652                 task = iscsi_itt_to_ctask(conn, hdr->itt);
653                 if (!task)
654                         rc = ISCSI_ERR_BAD_ITT;
655                 else
656                         rc = iscsi_tcp_data_in(conn, task);
657                 if (rc) {
658                         spin_unlock(&conn->session->lock);
659                         break;
660                 }
661
662                 if (tcp_conn->in.datalen) {
663                         struct iscsi_tcp_task *tcp_task = task->dd_data;
664                         struct hash_desc *rx_hash = NULL;
665                         struct scsi_data_buffer *sdb = scsi_in(task->sc);
666
667                         /*
668                          * Setup copy of Data-In into the Scsi_Cmnd
669                          * Scatterlist case:
670                          * We set up the iscsi_segment to point to the next
671                          * scatterlist entry to copy to. As we go along,
672                          * we move on to the next scatterlist entry and
673                          * update the digest per-entry.
674                          */
675                         if (conn->datadgst_en &&
676                             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
677                                 rx_hash = tcp_conn->rx_hash;
678
679                         ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
680                                      "offset=%d, datalen=%d)\n",
681                                       tcp_task->data_offset,
682                                       tcp_conn->in.datalen);
683                         rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
684                                                    sdb->table.sgl,
685                                                    sdb->table.nents,
686                                                    tcp_task->data_offset,
687                                                    tcp_conn->in.datalen,
688                                                    iscsi_tcp_process_data_in,
689                                                    rx_hash);
690                         spin_unlock(&conn->session->lock);
691                         return rc;
692                 }
693                 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
694                 spin_unlock(&conn->session->lock);
695                 break;
696         case ISCSI_OP_SCSI_CMD_RSP:
697                 if (tcp_conn->in.datalen) {
698                         iscsi_tcp_data_recv_prep(tcp_conn);
699                         return 0;
700                 }
701                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
702                 break;
703         case ISCSI_OP_R2T:
704                 spin_lock(&conn->session->lock);
705                 task = iscsi_itt_to_ctask(conn, hdr->itt);
706                 if (!task)
707                         rc = ISCSI_ERR_BAD_ITT;
708                 else if (ahslen)
709                         rc = ISCSI_ERR_AHSLEN;
710                 else if (task->sc->sc_data_direction == DMA_TO_DEVICE)
711                         rc = iscsi_tcp_r2t_rsp(conn, task);
712                 else
713                         rc = ISCSI_ERR_PROTO;
714                 spin_unlock(&conn->session->lock);
715                 break;
716         case ISCSI_OP_LOGIN_RSP:
717         case ISCSI_OP_TEXT_RSP:
718         case ISCSI_OP_REJECT:
719         case ISCSI_OP_ASYNC_EVENT:
720                 /*
721                  * It is possible that we could get a PDU with a buffer larger
722                  * than 8K, but there are no targets that currently do this.
723                  * For now we fail until we find a vendor that needs it
724                  */
725                 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
726                         iscsi_conn_printk(KERN_ERR, conn,
727                                           "iscsi_tcp: received buffer of "
728                                           "len %u but conn buffer is only %u "
729                                           "(opcode %0x)\n",
730                                           tcp_conn->in.datalen,
731                                           ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
732                         rc = ISCSI_ERR_PROTO;
733                         break;
734                 }
735
736                 /* If there's data coming in with the response,
737                  * receive it to the connection's buffer.
738                  */
739                 if (tcp_conn->in.datalen) {
740                         iscsi_tcp_data_recv_prep(tcp_conn);
741                         return 0;
742                 }
743         /* fall through */
744         case ISCSI_OP_LOGOUT_RSP:
745         case ISCSI_OP_NOOP_IN:
746         case ISCSI_OP_SCSI_TMFUNC_RSP:
747                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
748                 break;
749         default:
750                 rc = ISCSI_ERR_BAD_OPCODE;
751                 break;
752         }
753
754         if (rc == 0) {
755                 /* Anything that comes with data should have
756                  * been handled above. */
757                 if (tcp_conn->in.datalen)
758                         return ISCSI_ERR_PROTO;
759                 iscsi_tcp_hdr_recv_prep(tcp_conn);
760         }
761
762         return rc;
763 }
764
765 /**
766  * iscsi_tcp_hdr_recv_done - process PDU header
767  *
768  * This is the callback invoked when the PDU header has
769  * been received. If the header is followed by additional
770  * header segments, we go back for more data.
771  */
772 static int
773 iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
774                         struct iscsi_segment *segment)
775 {
776         struct iscsi_conn *conn = tcp_conn->iscsi_conn;
777         struct iscsi_hdr *hdr;
778
779         /* Check if there are additional header segments
780          * *prior* to computing the digest, because we
781          * may need to go back to the caller for more.
782          */
783         hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
784         if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
785                 /* Bump the header length - the caller will
786                  * just loop around and get the AHS for us, and
787                  * call again. */
788                 unsigned int ahslen = hdr->hlength << 2;
789
790                 /* Make sure we don't overflow */
791                 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
792                         return ISCSI_ERR_AHSLEN;
793
794                 segment->total_size += ahslen;
795                 segment->size += ahslen;
796                 return 0;
797         }
798
799         /* We're done processing the header. See if we're doing
800          * header digests; if so, set up the recv_digest buffer
801          * and go back for more. */
802         if (conn->hdrdgst_en &&
803             !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
804                 if (segment->digest_len == 0) {
805                         /*
806                          * Even if we offload the digest processing we
807                          * splice it in so we can increment the skb/segment
808                          * counters in preparation for the data segment.
809                          */
810                         iscsi_tcp_segment_splice_digest(segment,
811                                                         segment->recv_digest);
812                         return 0;
813                 }
814
815                 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
816                                       segment->total_copied - ISCSI_DIGEST_SIZE,
817                                       segment->digest);
818
819                 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
820                         return ISCSI_ERR_HDR_DGST;
821         }
822
823         tcp_conn->in.hdr = hdr;
824         return iscsi_tcp_hdr_dissect(conn, hdr);
825 }
826
827 /**
828  * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
829  * @tcp_conn: iscsi tcp conn
830  *
831  * returns non zero if we are currently processing or setup to process
832  * a header.
833  */
834 inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
835 {
836         return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
837 }
838 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
839
840 /**
841  * iscsi_tcp_recv_skb - Process skb
842  * @conn: iscsi connection
843  * @skb: network buffer with header and/or data segment
844  * @offset: offset in skb
845  * @offload: bool indicating if transfer was offloaded
846  *
847  * Will return status of transfer in status. And will return
848  * number of bytes copied.
849  */
850 int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
851                        unsigned int offset, bool offloaded, int *status)
852 {
853         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
854         struct iscsi_segment *segment = &tcp_conn->in.segment;
855         struct skb_seq_state seq;
856         unsigned int consumed = 0;
857         int rc = 0;
858
859         ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
860
861         if (unlikely(conn->suspend_rx)) {
862                 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
863                 *status = ISCSI_TCP_SUSPENDED;
864                 return 0;
865         }
866
867         if (offloaded) {
868                 segment->total_copied = segment->total_size;
869                 goto segment_done;
870         }
871
872         skb_prepare_seq_read(skb, offset, skb->len, &seq);
873         while (1) {
874                 unsigned int avail;
875                 const u8 *ptr;
876
877                 avail = skb_seq_read(consumed, &ptr, &seq);
878                 if (avail == 0) {
879                         ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
880                                       consumed);
881                         *status = ISCSI_TCP_SKB_DONE;
882                         skb_abort_seq_read(&seq);
883                         goto skb_done;
884                 }
885                 BUG_ON(segment->copied >= segment->size);
886
887                 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
888                               avail);
889                 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
890                 BUG_ON(rc == 0);
891                 consumed += rc;
892
893                 if (segment->total_copied >= segment->total_size) {
894                         skb_abort_seq_read(&seq);
895                         goto segment_done;
896                 }
897         }
898
899 segment_done:
900         *status = ISCSI_TCP_SEGMENT_DONE;
901         ISCSI_DBG_TCP(conn, "segment done\n");
902         rc = segment->done(tcp_conn, segment);
903         if (rc != 0) {
904                 *status = ISCSI_TCP_CONN_ERR;
905                 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
906                 iscsi_conn_failure(conn, rc);
907                 return 0;
908         }
909         /* The done() functions sets up the next segment. */
910
911 skb_done:
912         conn->rxdata_octets += consumed;
913         return consumed;
914 }
915 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
916
917 /**
918  * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
919  * @conn: iscsi connection
920  * @task: scsi command task
921  * @sc: scsi command
922  */
923 int iscsi_tcp_task_init(struct iscsi_task *task)
924 {
925         struct iscsi_tcp_task *tcp_task = task->dd_data;
926         struct iscsi_conn *conn = task->conn;
927         struct scsi_cmnd *sc = task->sc;
928         int err;
929
930         if (!sc) {
931                 /*
932                  * mgmt tasks do not have a scatterlist since they come
933                  * in from the iscsi interface.
934                  */
935                 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
936
937                 return conn->session->tt->init_pdu(task, 0, task->data_count);
938         }
939
940         BUG_ON(__kfifo_len(tcp_task->r2tqueue));
941         tcp_task->exp_datasn = 0;
942
943         /* Prepare PDU, optionally w/ immediate data */
944         ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
945                       task->itt, task->imm_count, task->unsol_r2t.data_length);
946
947         err = conn->session->tt->init_pdu(task, 0, task->imm_count);
948         if (err)
949                 return err;
950         task->imm_count = 0;
951         return 0;
952 }
953 EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
954
955 static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
956 {
957         struct iscsi_session *session = task->conn->session;
958         struct iscsi_tcp_task *tcp_task = task->dd_data;
959         struct iscsi_r2t_info *r2t = NULL;
960
961         if (iscsi_task_has_unsol_data(task))
962                 r2t = &task->unsol_r2t;
963         else {
964                 spin_lock_bh(&session->lock);
965                 if (tcp_task->r2t) {
966                         r2t = tcp_task->r2t;
967                         /* Continue with this R2T? */
968                         if (r2t->data_length <= r2t->sent) {
969                                 ISCSI_DBG_TCP(task->conn,
970                                               "  done with r2t %p\n", r2t);
971                                 __kfifo_put(tcp_task->r2tpool.queue,
972                                             (void *)&tcp_task->r2t,
973                                             sizeof(void *));
974                                 tcp_task->r2t = r2t = NULL;
975                         }
976                 }
977
978                 if (r2t == NULL) {
979                         __kfifo_get(tcp_task->r2tqueue,
980                                     (void *)&tcp_task->r2t, sizeof(void *));
981                         r2t = tcp_task->r2t;
982                 }
983                 spin_unlock_bh(&session->lock);
984         }
985
986         return r2t;
987 }
988
989 /**
990  * iscsi_tcp_task_xmit - xmit normal PDU task
991  * @task: iscsi command task
992  *
993  * We're expected to return 0 when everything was transmitted succesfully,
994  * -EAGAIN if there's still data in the queue, or != 0 for any other kind
995  * of error.
996  */
997 int iscsi_tcp_task_xmit(struct iscsi_task *task)
998 {
999         struct iscsi_conn *conn = task->conn;
1000         struct iscsi_session *session = conn->session;
1001         struct iscsi_r2t_info *r2t;
1002         int rc = 0;
1003
1004 flush:
1005         /* Flush any pending data first. */
1006         rc = session->tt->xmit_pdu(task);
1007         if (rc < 0)
1008                 return rc;
1009
1010         /* mgmt command */
1011         if (!task->sc) {
1012                 if (task->hdr->itt == RESERVED_ITT)
1013                         iscsi_put_task(task);
1014                 return 0;
1015         }
1016
1017         /* Are we done already? */
1018         if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1019                 return 0;
1020
1021         r2t = iscsi_tcp_get_curr_r2t(task);
1022         if (r2t == NULL) {
1023                 /* Waiting for more R2Ts to arrive. */
1024                 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1025                 return 0;
1026         }
1027
1028         rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1029         if (rc)
1030                 return rc;
1031         iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1032
1033         ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1034                       r2t, r2t->datasn - 1, task->hdr->itt,
1035                       r2t->data_offset + r2t->sent, r2t->data_count);
1036
1037         rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1038                                          r2t->data_count);
1039         if (rc)
1040                 return rc;
1041         r2t->sent += r2t->data_count;
1042         goto flush;
1043 }
1044 EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1045
1046 struct iscsi_cls_conn *
1047 iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1048                       uint32_t conn_idx)
1049
1050 {
1051         struct iscsi_conn *conn;
1052         struct iscsi_cls_conn *cls_conn;
1053         struct iscsi_tcp_conn *tcp_conn;
1054
1055         cls_conn = iscsi_conn_setup(cls_session, sizeof(*tcp_conn), conn_idx);
1056         if (!cls_conn)
1057                 return NULL;
1058         conn = cls_conn->dd_data;
1059         /*
1060          * due to strange issues with iser these are not set
1061          * in iscsi_conn_setup
1062          */
1063         conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1064
1065         tcp_conn = conn->dd_data;
1066         tcp_conn->iscsi_conn = conn;
1067
1068         tcp_conn->dd_data = kzalloc(dd_data_size, GFP_KERNEL);
1069         if (!tcp_conn->dd_data) {
1070                 iscsi_conn_teardown(cls_conn);
1071                 return NULL;
1072         }
1073         return cls_conn;
1074 }
1075 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1076
1077 void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1078 {
1079         struct iscsi_conn *conn = cls_conn->dd_data;
1080         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1081
1082         kfree(tcp_conn->dd_data);
1083         iscsi_conn_teardown(cls_conn);
1084 }
1085 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1086
1087 int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1088 {
1089         int i;
1090         int cmd_i;
1091
1092         /*
1093          * initialize per-task: R2T pool and xmit queue
1094          */
1095         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1096                 struct iscsi_task *task = session->cmds[cmd_i];
1097                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1098
1099                 /*
1100                  * pre-allocated x2 as much r2ts to handle race when
1101                  * target acks DataOut faster than we data_xmit() queues
1102                  * could replenish r2tqueue.
1103                  */
1104
1105                 /* R2T pool */
1106                 if (iscsi_pool_init(&tcp_task->r2tpool,
1107                                     session->max_r2t * 2, NULL,
1108                                     sizeof(struct iscsi_r2t_info))) {
1109                         goto r2t_alloc_fail;
1110                 }
1111
1112                 /* R2T xmit queue */
1113                 tcp_task->r2tqueue = kfifo_alloc(
1114                       session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL);
1115                 if (tcp_task->r2tqueue == ERR_PTR(-ENOMEM)) {
1116                         iscsi_pool_free(&tcp_task->r2tpool);
1117                         goto r2t_alloc_fail;
1118                 }
1119         }
1120
1121         return 0;
1122
1123 r2t_alloc_fail:
1124         for (i = 0; i < cmd_i; i++) {
1125                 struct iscsi_task *task = session->cmds[i];
1126                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1127
1128                 kfifo_free(tcp_task->r2tqueue);
1129                 iscsi_pool_free(&tcp_task->r2tpool);
1130         }
1131         return -ENOMEM;
1132 }
1133 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1134
1135 void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1136 {
1137         int i;
1138
1139         for (i = 0; i < session->cmds_max; i++) {
1140                 struct iscsi_task *task = session->cmds[i];
1141                 struct iscsi_tcp_task *tcp_task = task->dd_data;
1142
1143                 kfifo_free(tcp_task->r2tqueue);
1144                 iscsi_pool_free(&tcp_task->r2tpool);
1145         }
1146 }
1147 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1148
1149 void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1150                               struct iscsi_stats *stats)
1151 {
1152         struct iscsi_conn *conn = cls_conn->dd_data;
1153
1154         stats->txdata_octets = conn->txdata_octets;
1155         stats->rxdata_octets = conn->rxdata_octets;
1156         stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1157         stats->dataout_pdus = conn->dataout_pdus_cnt;
1158         stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1159         stats->datain_pdus = conn->datain_pdus_cnt;
1160         stats->r2t_pdus = conn->r2t_pdus_cnt;
1161         stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1162         stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1163 }
1164 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);