Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
[linux-2.6.git] / drivers / scsi / iscsi_tcp.c
1 /*
2  * iSCSI Initiator over TCP/IP Data-Path
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/err.h>
30 #include <linux/types.h>
31 #include <linux/list.h>
32 #include <linux/inet.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 <linux/mutex.h>
39 #include <net/tcp.h>
40 #include <scsi/scsi_cmnd.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("Dmitry Yusupov <dmitry_yus@yahoo.com>, "
48               "Alex Aizman <itn780@yahoo.com>");
49 MODULE_DESCRIPTION("iSCSI/TCP data-path");
50 MODULE_LICENSE("GPL");
51 /* #define DEBUG_TCP */
52 #define DEBUG_ASSERT
53
54 #ifdef DEBUG_TCP
55 #define debug_tcp(fmt...) printk(KERN_INFO "tcp: " fmt)
56 #else
57 #define debug_tcp(fmt...)
58 #endif
59
60 #ifndef DEBUG_ASSERT
61 #ifdef BUG_ON
62 #undef BUG_ON
63 #endif
64 #define BUG_ON(expr)
65 #endif
66
67 static unsigned int iscsi_max_lun = 512;
68 module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);
69
70 static inline void
71 iscsi_buf_init_iov(struct iscsi_buf *ibuf, char *vbuf, int size)
72 {
73         ibuf->sg.page = virt_to_page(vbuf);
74         ibuf->sg.offset = offset_in_page(vbuf);
75         ibuf->sg.length = size;
76         ibuf->sent = 0;
77         ibuf->use_sendmsg = 1;
78 }
79
80 static inline void
81 iscsi_buf_init_sg(struct iscsi_buf *ibuf, struct scatterlist *sg)
82 {
83         ibuf->sg.page = sg->page;
84         ibuf->sg.offset = sg->offset;
85         ibuf->sg.length = sg->length;
86         /*
87          * Fastpath: sg element fits into single page
88          */
89         if (sg->length + sg->offset <= PAGE_SIZE && !PageSlab(sg->page))
90                 ibuf->use_sendmsg = 0;
91         else
92                 ibuf->use_sendmsg = 1;
93         ibuf->sent = 0;
94 }
95
96 static inline int
97 iscsi_buf_left(struct iscsi_buf *ibuf)
98 {
99         int rc;
100
101         rc = ibuf->sg.length - ibuf->sent;
102         BUG_ON(rc < 0);
103         return rc;
104 }
105
106 static inline void
107 iscsi_hdr_digest(struct iscsi_conn *conn, struct iscsi_buf *buf,
108                  u8* crc)
109 {
110         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
111         struct hash_desc desc;
112
113         desc.tfm = tcp_conn->tx_tfm;
114         desc.flags = 0;
115         crypto_hash_digest(&desc, &buf->sg, buf->sg.length, crc);
116         buf->sg.length += sizeof(uint32_t);
117 }
118
119 static inline int
120 iscsi_hdr_extract(struct iscsi_tcp_conn *tcp_conn)
121 {
122         struct sk_buff *skb = tcp_conn->in.skb;
123
124         tcp_conn->in.zero_copy_hdr = 0;
125
126         if (tcp_conn->in.copy >= tcp_conn->hdr_size &&
127             tcp_conn->in_progress == IN_PROGRESS_WAIT_HEADER) {
128                 /*
129                  * Zero-copy PDU Header: using connection context
130                  * to store header pointer.
131                  */
132                 if (skb_shinfo(skb)->frag_list == NULL &&
133                     !skb_shinfo(skb)->nr_frags) {
134                         tcp_conn->in.hdr = (struct iscsi_hdr *)
135                                 ((char*)skb->data + tcp_conn->in.offset);
136                         tcp_conn->in.zero_copy_hdr = 1;
137                 } else {
138                         /* ignoring return code since we checked
139                          * in.copy before */
140                         skb_copy_bits(skb, tcp_conn->in.offset,
141                                 &tcp_conn->hdr, tcp_conn->hdr_size);
142                         tcp_conn->in.hdr = &tcp_conn->hdr;
143                 }
144                 tcp_conn->in.offset += tcp_conn->hdr_size;
145                 tcp_conn->in.copy -= tcp_conn->hdr_size;
146         } else {
147                 int hdr_remains;
148                 int copylen;
149
150                 /*
151                  * PDU header scattered across SKB's,
152                  * copying it... This'll happen quite rarely.
153                  */
154
155                 if (tcp_conn->in_progress == IN_PROGRESS_WAIT_HEADER)
156                         tcp_conn->in.hdr_offset = 0;
157
158                 hdr_remains = tcp_conn->hdr_size - tcp_conn->in.hdr_offset;
159                 BUG_ON(hdr_remains <= 0);
160
161                 copylen = min(tcp_conn->in.copy, hdr_remains);
162                 skb_copy_bits(skb, tcp_conn->in.offset,
163                         (char*)&tcp_conn->hdr + tcp_conn->in.hdr_offset,
164                         copylen);
165
166                 debug_tcp("PDU gather offset %d bytes %d in.offset %d "
167                        "in.copy %d\n", tcp_conn->in.hdr_offset, copylen,
168                        tcp_conn->in.offset, tcp_conn->in.copy);
169
170                 tcp_conn->in.offset += copylen;
171                 tcp_conn->in.copy -= copylen;
172                 if (copylen < hdr_remains)  {
173                         tcp_conn->in_progress = IN_PROGRESS_HEADER_GATHER;
174                         tcp_conn->in.hdr_offset += copylen;
175                         return -EAGAIN;
176                 }
177                 tcp_conn->in.hdr = &tcp_conn->hdr;
178                 tcp_conn->discontiguous_hdr_cnt++;
179                 tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
180         }
181
182         return 0;
183 }
184
185 /*
186  * must be called with session lock
187  */
188 static void
189 iscsi_tcp_cleanup_ctask(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
190 {
191         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
192         struct iscsi_r2t_info *r2t;
193         struct scsi_cmnd *sc;
194
195         /* flush ctask's r2t queues */
196         while (__kfifo_get(tcp_ctask->r2tqueue, (void*)&r2t, sizeof(void*))) {
197                 __kfifo_put(tcp_ctask->r2tpool.queue, (void*)&r2t,
198                             sizeof(void*));
199                 debug_scsi("iscsi_tcp_cleanup_ctask pending r2t dropped\n");
200         }
201
202         sc = ctask->sc;
203         if (unlikely(!sc))
204                 return;
205
206         tcp_ctask->xmstate = XMSTATE_IDLE;
207         tcp_ctask->r2t = NULL;
208 }
209
210 /**
211  * iscsi_data_rsp - SCSI Data-In Response processing
212  * @conn: iscsi connection
213  * @ctask: scsi command task
214  **/
215 static int
216 iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
217 {
218         int rc;
219         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
220         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
221         struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
222         struct iscsi_session *session = conn->session;
223         int datasn = be32_to_cpu(rhdr->datasn);
224
225         rc = iscsi_check_assign_cmdsn(session, (struct iscsi_nopin*)rhdr);
226         if (rc)
227                 return rc;
228         /*
229          * setup Data-In byte counter (gets decremented..)
230          */
231         ctask->data_count = tcp_conn->in.datalen;
232
233         if (tcp_conn->in.datalen == 0)
234                 return 0;
235
236         if (ctask->datasn != datasn)
237                 return ISCSI_ERR_DATASN;
238
239         ctask->datasn++;
240
241         tcp_ctask->data_offset = be32_to_cpu(rhdr->offset);
242         if (tcp_ctask->data_offset + tcp_conn->in.datalen > ctask->total_length)
243                 return ISCSI_ERR_DATA_OFFSET;
244
245         if (rhdr->flags & ISCSI_FLAG_DATA_STATUS) {
246                 struct scsi_cmnd *sc = ctask->sc;
247
248                 conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
249                 if (rhdr->flags & ISCSI_FLAG_DATA_UNDERFLOW) {
250                         int res_count = be32_to_cpu(rhdr->residual_count);
251
252                         if (res_count > 0 &&
253                             res_count <= sc->request_bufflen) {
254                                 sc->resid = res_count;
255                                 sc->result = (DID_OK << 16) | rhdr->cmd_status;
256                         } else
257                                 sc->result = (DID_BAD_TARGET << 16) |
258                                         rhdr->cmd_status;
259                 } else if (rhdr->flags & ISCSI_FLAG_DATA_OVERFLOW) {
260                         sc->resid = be32_to_cpu(rhdr->residual_count);
261                         sc->result = (DID_OK << 16) | rhdr->cmd_status;
262                 } else
263                         sc->result = (DID_OK << 16) | rhdr->cmd_status;
264         }
265
266         conn->datain_pdus_cnt++;
267         return 0;
268 }
269
270 /**
271  * iscsi_solicit_data_init - initialize first Data-Out
272  * @conn: iscsi connection
273  * @ctask: scsi command task
274  * @r2t: R2T info
275  *
276  * Notes:
277  *      Initialize first Data-Out within this R2T sequence and finds
278  *      proper data_offset within this SCSI command.
279  *
280  *      This function is called with connection lock taken.
281  **/
282 static void
283 iscsi_solicit_data_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
284                         struct iscsi_r2t_info *r2t)
285 {
286         struct iscsi_data *hdr;
287         struct scsi_cmnd *sc = ctask->sc;
288         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
289
290         hdr = &r2t->dtask.hdr;
291         memset(hdr, 0, sizeof(struct iscsi_data));
292         hdr->ttt = r2t->ttt;
293         hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
294         r2t->solicit_datasn++;
295         hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
296         memcpy(hdr->lun, ctask->hdr->lun, sizeof(hdr->lun));
297         hdr->itt = ctask->hdr->itt;
298         hdr->exp_statsn = r2t->exp_statsn;
299         hdr->offset = cpu_to_be32(r2t->data_offset);
300         if (r2t->data_length > conn->max_xmit_dlength) {
301                 hton24(hdr->dlength, conn->max_xmit_dlength);
302                 r2t->data_count = conn->max_xmit_dlength;
303                 hdr->flags = 0;
304         } else {
305                 hton24(hdr->dlength, r2t->data_length);
306                 r2t->data_count = r2t->data_length;
307                 hdr->flags = ISCSI_FLAG_CMD_FINAL;
308         }
309         conn->dataout_pdus_cnt++;
310
311         r2t->sent = 0;
312
313         iscsi_buf_init_iov(&r2t->headbuf, (char*)hdr,
314                            sizeof(struct iscsi_hdr));
315
316         if (sc->use_sg) {
317                 int i, sg_count = 0;
318                 struct scatterlist *sg = sc->request_buffer;
319
320                 r2t->sg = NULL;
321                 for (i = 0; i < sc->use_sg; i++, sg += 1) {
322                         /* FIXME: prefetch ? */
323                         if (sg_count + sg->length > r2t->data_offset) {
324                                 int page_offset;
325
326                                 /* sg page found! */
327
328                                 /* offset within this page */
329                                 page_offset = r2t->data_offset - sg_count;
330
331                                 /* fill in this buffer */
332                                 iscsi_buf_init_sg(&r2t->sendbuf, sg);
333                                 r2t->sendbuf.sg.offset += page_offset;
334                                 r2t->sendbuf.sg.length -= page_offset;
335
336                                 /* xmit logic will continue with next one */
337                                 r2t->sg = sg + 1;
338                                 break;
339                         }
340                         sg_count += sg->length;
341                 }
342                 BUG_ON(r2t->sg == NULL);
343         } else
344                 iscsi_buf_init_iov(&tcp_ctask->sendbuf,
345                             (char*)sc->request_buffer + r2t->data_offset,
346                             r2t->data_count);
347 }
348
349 /**
350  * iscsi_r2t_rsp - iSCSI R2T Response processing
351  * @conn: iscsi connection
352  * @ctask: scsi command task
353  **/
354 static int
355 iscsi_r2t_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
356 {
357         struct iscsi_r2t_info *r2t;
358         struct iscsi_session *session = conn->session;
359         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
360         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
361         struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
362         int r2tsn = be32_to_cpu(rhdr->r2tsn);
363         int rc;
364
365         if (tcp_conn->in.datalen)
366                 return ISCSI_ERR_DATALEN;
367
368         if (tcp_ctask->exp_r2tsn && tcp_ctask->exp_r2tsn != r2tsn)
369                 return ISCSI_ERR_R2TSN;
370
371         rc = iscsi_check_assign_cmdsn(session, (struct iscsi_nopin*)rhdr);
372         if (rc)
373                 return rc;
374
375         /* FIXME: use R2TSN to detect missing R2T */
376
377         /* fill-in new R2T associated with the task */
378         spin_lock(&session->lock);
379         if (!ctask->sc || ctask->mtask ||
380              session->state != ISCSI_STATE_LOGGED_IN) {
381                 printk(KERN_INFO "iscsi_tcp: dropping R2T itt %d in "
382                        "recovery...\n", ctask->itt);
383                 spin_unlock(&session->lock);
384                 return 0;
385         }
386
387         rc = __kfifo_get(tcp_ctask->r2tpool.queue, (void*)&r2t, sizeof(void*));
388         BUG_ON(!rc);
389
390         r2t->exp_statsn = rhdr->statsn;
391         r2t->data_length = be32_to_cpu(rhdr->data_length);
392         if (r2t->data_length == 0 ||
393             r2t->data_length > session->max_burst) {
394                 spin_unlock(&session->lock);
395                 return ISCSI_ERR_DATALEN;
396         }
397
398         r2t->data_offset = be32_to_cpu(rhdr->data_offset);
399         if (r2t->data_offset + r2t->data_length > ctask->total_length) {
400                 spin_unlock(&session->lock);
401                 return ISCSI_ERR_DATALEN;
402         }
403
404         r2t->ttt = rhdr->ttt; /* no flip */
405         r2t->solicit_datasn = 0;
406
407         iscsi_solicit_data_init(conn, ctask, r2t);
408
409         tcp_ctask->exp_r2tsn = r2tsn + 1;
410         tcp_ctask->xmstate |= XMSTATE_SOL_HDR;
411         __kfifo_put(tcp_ctask->r2tqueue, (void*)&r2t, sizeof(void*));
412         list_move_tail(&ctask->running, &conn->xmitqueue);
413
414         scsi_queue_work(session->host, &conn->xmitwork);
415         conn->r2t_pdus_cnt++;
416         spin_unlock(&session->lock);
417
418         return 0;
419 }
420
421 static int
422 iscsi_tcp_hdr_recv(struct iscsi_conn *conn)
423 {
424         int rc = 0, opcode, ahslen;
425         struct iscsi_hdr *hdr;
426         struct iscsi_session *session = conn->session;
427         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
428         uint32_t cdgst, rdgst = 0, itt;
429
430         hdr = tcp_conn->in.hdr;
431
432         /* verify PDU length */
433         tcp_conn->in.datalen = ntoh24(hdr->dlength);
434         if (tcp_conn->in.datalen > conn->max_recv_dlength) {
435                 printk(KERN_ERR "iscsi_tcp: datalen %d > %d\n",
436                        tcp_conn->in.datalen, conn->max_recv_dlength);
437                 return ISCSI_ERR_DATALEN;
438         }
439         tcp_conn->data_copied = 0;
440
441         /* read AHS */
442         ahslen = hdr->hlength << 2;
443         tcp_conn->in.offset += ahslen;
444         tcp_conn->in.copy -= ahslen;
445         if (tcp_conn->in.copy < 0) {
446                 printk(KERN_ERR "iscsi_tcp: can't handle AHS with length "
447                        "%d bytes\n", ahslen);
448                 return ISCSI_ERR_AHSLEN;
449         }
450
451         /* calculate read padding */
452         tcp_conn->in.padding = tcp_conn->in.datalen & (ISCSI_PAD_LEN-1);
453         if (tcp_conn->in.padding) {
454                 tcp_conn->in.padding = ISCSI_PAD_LEN - tcp_conn->in.padding;
455                 debug_scsi("read padding %d bytes\n", tcp_conn->in.padding);
456         }
457
458         if (conn->hdrdgst_en) {
459                 struct hash_desc desc;
460                 struct scatterlist sg;
461
462                 sg_init_one(&sg, (u8 *)hdr,
463                             sizeof(struct iscsi_hdr) + ahslen);
464                 desc.tfm = tcp_conn->rx_tfm;
465                 desc.flags = 0;
466                 crypto_hash_digest(&desc, &sg, sg.length, (u8 *)&cdgst);
467                 rdgst = *(uint32_t*)((char*)hdr + sizeof(struct iscsi_hdr) +
468                                      ahslen);
469                 if (cdgst != rdgst) {
470                         printk(KERN_ERR "iscsi_tcp: hdrdgst error "
471                                "recv 0x%x calc 0x%x\n", rdgst, cdgst);
472                         return ISCSI_ERR_HDR_DGST;
473                 }
474         }
475
476         opcode = hdr->opcode & ISCSI_OPCODE_MASK;
477         /* verify itt (itt encoding: age+cid+itt) */
478         rc = iscsi_verify_itt(conn, hdr, &itt);
479         if (rc == ISCSI_ERR_NO_SCSI_CMD) {
480                 tcp_conn->in.datalen = 0; /* force drop */
481                 return 0;
482         } else if (rc)
483                 return rc;
484
485         debug_tcp("opcode 0x%x offset %d copy %d ahslen %d datalen %d\n",
486                   opcode, tcp_conn->in.offset, tcp_conn->in.copy,
487                   ahslen, tcp_conn->in.datalen);
488
489         switch(opcode) {
490         case ISCSI_OP_SCSI_DATA_IN:
491                 tcp_conn->in.ctask = session->cmds[itt];
492                 rc = iscsi_data_rsp(conn, tcp_conn->in.ctask);
493                 if (rc)
494                         return rc;
495                 /* fall through */
496         case ISCSI_OP_SCSI_CMD_RSP:
497                 tcp_conn->in.ctask = session->cmds[itt];
498                 if (tcp_conn->in.datalen)
499                         goto copy_hdr;
500
501                 spin_lock(&session->lock);
502                 iscsi_tcp_cleanup_ctask(conn, tcp_conn->in.ctask);
503                 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
504                 spin_unlock(&session->lock);
505                 break;
506         case ISCSI_OP_R2T:
507                 tcp_conn->in.ctask = session->cmds[itt];
508                 if (ahslen)
509                         rc = ISCSI_ERR_AHSLEN;
510                 else if (tcp_conn->in.ctask->sc->sc_data_direction ==
511                                                                 DMA_TO_DEVICE)
512                         rc = iscsi_r2t_rsp(conn, tcp_conn->in.ctask);
513                 else
514                         rc = ISCSI_ERR_PROTO;
515                 break;
516         case ISCSI_OP_LOGIN_RSP:
517         case ISCSI_OP_TEXT_RSP:
518         case ISCSI_OP_REJECT:
519         case ISCSI_OP_ASYNC_EVENT:
520                 /*
521                  * It is possible that we could get a PDU with a buffer larger
522                  * than 8K, but there are no targets that currently do this.
523                  * For now we fail until we find a vendor that needs it
524                  */
525                 if (DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH <
526                     tcp_conn->in.datalen) {
527                         printk(KERN_ERR "iscsi_tcp: received buffer of len %u "
528                               "but conn buffer is only %u (opcode %0x)\n",
529                               tcp_conn->in.datalen,
530                               DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH, opcode);
531                         rc = ISCSI_ERR_PROTO;
532                         break;
533                 }
534
535                 if (tcp_conn->in.datalen)
536                         goto copy_hdr;
537         /* fall through */
538         case ISCSI_OP_LOGOUT_RSP:
539         case ISCSI_OP_NOOP_IN:
540         case ISCSI_OP_SCSI_TMFUNC_RSP:
541                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
542                 break;
543         default:
544                 rc = ISCSI_ERR_BAD_OPCODE;
545                 break;
546         }
547
548         return rc;
549
550 copy_hdr:
551         /*
552          * if we did zero copy for the header but we will need multiple
553          * skbs to complete the command then we have to copy the header
554          * for later use
555          */
556         if (tcp_conn->in.zero_copy_hdr && tcp_conn->in.copy <=
557            (tcp_conn->in.datalen + tcp_conn->in.padding +
558             (conn->datadgst_en ? 4 : 0))) {
559                 debug_tcp("Copying header for later use. in.copy %d in.datalen"
560                           " %d\n", tcp_conn->in.copy, tcp_conn->in.datalen);
561                 memcpy(&tcp_conn->hdr, tcp_conn->in.hdr,
562                        sizeof(struct iscsi_hdr));
563                 tcp_conn->in.hdr = &tcp_conn->hdr;
564                 tcp_conn->in.zero_copy_hdr = 0;
565         }
566         return 0;
567 }
568
569 /**
570  * iscsi_ctask_copy - copy skb bits to the destanation cmd task
571  * @conn: iscsi tcp connection
572  * @ctask: scsi command task
573  * @buf: buffer to copy to
574  * @buf_size: size of buffer
575  * @offset: offset within the buffer
576  *
577  * Notes:
578  *      The function calls skb_copy_bits() and updates per-connection and
579  *      per-cmd byte counters.
580  *
581  *      Read counters (in bytes):
582  *
583  *      conn->in.offset         offset within in progress SKB
584  *      conn->in.copy           left to copy from in progress SKB
585  *                              including padding
586  *      conn->in.copied         copied already from in progress SKB
587  *      conn->data_copied       copied already from in progress buffer
588  *      ctask->sent             total bytes sent up to the MidLayer
589  *      ctask->data_count       left to copy from in progress Data-In
590  *      buf_left                left to copy from in progress buffer
591  **/
592 static inline int
593 iscsi_ctask_copy(struct iscsi_tcp_conn *tcp_conn, struct iscsi_cmd_task *ctask,
594                 void *buf, int buf_size, int offset)
595 {
596         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
597         int buf_left = buf_size - (tcp_conn->data_copied + offset);
598         int size = min(tcp_conn->in.copy, buf_left);
599         int rc;
600
601         size = min(size, ctask->data_count);
602
603         debug_tcp("ctask_copy %d bytes at offset %d copied %d\n",
604                size, tcp_conn->in.offset, tcp_conn->in.copied);
605
606         BUG_ON(size <= 0);
607         BUG_ON(tcp_ctask->sent + size > ctask->total_length);
608
609         rc = skb_copy_bits(tcp_conn->in.skb, tcp_conn->in.offset,
610                            (char*)buf + (offset + tcp_conn->data_copied), size);
611         /* must fit into skb->len */
612         BUG_ON(rc);
613
614         tcp_conn->in.offset += size;
615         tcp_conn->in.copy -= size;
616         tcp_conn->in.copied += size;
617         tcp_conn->data_copied += size;
618         tcp_ctask->sent += size;
619         ctask->data_count -= size;
620
621         BUG_ON(tcp_conn->in.copy < 0);
622         BUG_ON(ctask->data_count < 0);
623
624         if (buf_size != (tcp_conn->data_copied + offset)) {
625                 if (!ctask->data_count) {
626                         BUG_ON(buf_size - tcp_conn->data_copied < 0);
627                         /* done with this PDU */
628                         return buf_size - tcp_conn->data_copied;
629                 }
630                 return -EAGAIN;
631         }
632
633         /* done with this buffer or with both - PDU and buffer */
634         tcp_conn->data_copied = 0;
635         return 0;
636 }
637
638 /**
639  * iscsi_tcp_copy - copy skb bits to the destanation buffer
640  * @conn: iscsi tcp connection
641  *
642  * Notes:
643  *      The function calls skb_copy_bits() and updates per-connection
644  *      byte counters.
645  **/
646 static inline int
647 iscsi_tcp_copy(struct iscsi_conn *conn)
648 {
649         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
650         int buf_size = tcp_conn->in.datalen;
651         int buf_left = buf_size - tcp_conn->data_copied;
652         int size = min(tcp_conn->in.copy, buf_left);
653         int rc;
654
655         debug_tcp("tcp_copy %d bytes at offset %d copied %d\n",
656                size, tcp_conn->in.offset, tcp_conn->data_copied);
657         BUG_ON(size <= 0);
658
659         rc = skb_copy_bits(tcp_conn->in.skb, tcp_conn->in.offset,
660                            (char*)conn->data + tcp_conn->data_copied, size);
661         BUG_ON(rc);
662
663         tcp_conn->in.offset += size;
664         tcp_conn->in.copy -= size;
665         tcp_conn->in.copied += size;
666         tcp_conn->data_copied += size;
667
668         if (buf_size != tcp_conn->data_copied)
669                 return -EAGAIN;
670
671         return 0;
672 }
673
674 static inline void
675 partial_sg_digest_update(struct iscsi_tcp_conn *tcp_conn,
676                          struct scatterlist *sg, int offset, int length)
677 {
678         struct scatterlist temp;
679
680         memcpy(&temp, sg, sizeof(struct scatterlist));
681         temp.offset = offset;
682         temp.length = length;
683         crypto_hash_update(&tcp_conn->data_rx_hash, &temp, length);
684 }
685
686 static void
687 iscsi_recv_digest_update(struct iscsi_tcp_conn *tcp_conn, char* buf, int len)
688 {
689         struct scatterlist tmp;
690
691         sg_init_one(&tmp, buf, len);
692         crypto_hash_update(&tcp_conn->data_rx_hash, &tmp, len);
693 }
694
695 static int iscsi_scsi_data_in(struct iscsi_conn *conn)
696 {
697         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
698         struct iscsi_cmd_task *ctask = tcp_conn->in.ctask;
699         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
700         struct scsi_cmnd *sc = ctask->sc;
701         struct scatterlist *sg;
702         int i, offset, rc = 0;
703
704         BUG_ON((void*)ctask != sc->SCp.ptr);
705
706         /*
707          * copying Data-In into the Scsi_Cmnd
708          */
709         if (!sc->use_sg) {
710                 i = ctask->data_count;
711                 rc = iscsi_ctask_copy(tcp_conn, ctask, sc->request_buffer,
712                                       sc->request_bufflen,
713                                       tcp_ctask->data_offset);
714                 if (rc == -EAGAIN)
715                         return rc;
716                 if (conn->datadgst_en)
717                         iscsi_recv_digest_update(tcp_conn, sc->request_buffer,
718                                                  i);
719                 rc = 0;
720                 goto done;
721         }
722
723         offset = tcp_ctask->data_offset;
724         sg = sc->request_buffer;
725
726         if (tcp_ctask->data_offset)
727                 for (i = 0; i < tcp_ctask->sg_count; i++)
728                         offset -= sg[i].length;
729         /* we've passed through partial sg*/
730         if (offset < 0)
731                 offset = 0;
732
733         for (i = tcp_ctask->sg_count; i < sc->use_sg; i++) {
734                 char *dest;
735
736                 dest = kmap_atomic(sg[i].page, KM_SOFTIRQ0);
737                 rc = iscsi_ctask_copy(tcp_conn, ctask, dest + sg[i].offset,
738                                       sg[i].length, offset);
739                 kunmap_atomic(dest, KM_SOFTIRQ0);
740                 if (rc == -EAGAIN)
741                         /* continue with the next SKB/PDU */
742                         return rc;
743                 if (!rc) {
744                         if (conn->datadgst_en) {
745                                 if (!offset)
746                                         crypto_hash_update(
747                                                         &tcp_conn->data_rx_hash,
748                                                         &sg[i], sg[i].length);
749                                 else
750                                         partial_sg_digest_update(tcp_conn,
751                                                         &sg[i],
752                                                         sg[i].offset + offset,
753                                                         sg[i].length - offset);
754                         }
755                         offset = 0;
756                         tcp_ctask->sg_count++;
757                 }
758
759                 if (!ctask->data_count) {
760                         if (rc && conn->datadgst_en)
761                                 /*
762                                  * data-in is complete, but buffer not...
763                                  */
764                                 partial_sg_digest_update(tcp_conn, &sg[i],
765                                                 sg[i].offset, sg[i].length-rc);
766                         rc = 0;
767                         break;
768                 }
769
770                 if (!tcp_conn->in.copy)
771                         return -EAGAIN;
772         }
773         BUG_ON(ctask->data_count);
774
775 done:
776         /* check for non-exceptional status */
777         if (tcp_conn->in.hdr->flags & ISCSI_FLAG_DATA_STATUS) {
778                 debug_scsi("done [sc %lx res %d itt 0x%x flags 0x%x]\n",
779                            (long)sc, sc->result, ctask->itt,
780                            tcp_conn->in.hdr->flags);
781                 spin_lock(&conn->session->lock);
782                 iscsi_tcp_cleanup_ctask(conn, ctask);
783                 __iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
784                 spin_unlock(&conn->session->lock);
785         }
786
787         return rc;
788 }
789
790 static int
791 iscsi_data_recv(struct iscsi_conn *conn)
792 {
793         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
794         int rc = 0, opcode;
795
796         opcode = tcp_conn->in.hdr->opcode & ISCSI_OPCODE_MASK;
797         switch (opcode) {
798         case ISCSI_OP_SCSI_DATA_IN:
799                 rc = iscsi_scsi_data_in(conn);
800                 break;
801         case ISCSI_OP_SCSI_CMD_RSP:
802                 spin_lock(&conn->session->lock);
803                 iscsi_tcp_cleanup_ctask(conn, tcp_conn->in.ctask);
804                 spin_unlock(&conn->session->lock);
805         case ISCSI_OP_TEXT_RSP:
806         case ISCSI_OP_LOGIN_RSP:
807         case ISCSI_OP_ASYNC_EVENT:
808         case ISCSI_OP_REJECT:
809                 /*
810                  * Collect data segment to the connection's data
811                  * placeholder
812                  */
813                 if (iscsi_tcp_copy(conn)) {
814                         rc = -EAGAIN;
815                         goto exit;
816                 }
817
818                 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, conn->data,
819                                         tcp_conn->in.datalen);
820                 if (!rc && conn->datadgst_en && opcode != ISCSI_OP_LOGIN_RSP)
821                         iscsi_recv_digest_update(tcp_conn, conn->data,
822                                                 tcp_conn->in.datalen);
823                 break;
824         default:
825                 BUG_ON(1);
826         }
827 exit:
828         return rc;
829 }
830
831 /**
832  * iscsi_tcp_data_recv - TCP receive in sendfile fashion
833  * @rd_desc: read descriptor
834  * @skb: socket buffer
835  * @offset: offset in skb
836  * @len: skb->len - offset
837  **/
838 static int
839 iscsi_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
840                 unsigned int offset, size_t len)
841 {
842         int rc;
843         struct iscsi_conn *conn = rd_desc->arg.data;
844         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
845         int processed;
846         char pad[ISCSI_PAD_LEN];
847         struct scatterlist sg;
848
849         /*
850          * Save current SKB and its offset in the corresponding
851          * connection context.
852          */
853         tcp_conn->in.copy = skb->len - offset;
854         tcp_conn->in.offset = offset;
855         tcp_conn->in.skb = skb;
856         tcp_conn->in.len = tcp_conn->in.copy;
857         BUG_ON(tcp_conn->in.copy <= 0);
858         debug_tcp("in %d bytes\n", tcp_conn->in.copy);
859
860 more:
861         tcp_conn->in.copied = 0;
862         rc = 0;
863
864         if (unlikely(conn->suspend_rx)) {
865                 debug_tcp("conn %d Rx suspended!\n", conn->id);
866                 return 0;
867         }
868
869         if (tcp_conn->in_progress == IN_PROGRESS_WAIT_HEADER ||
870             tcp_conn->in_progress == IN_PROGRESS_HEADER_GATHER) {
871                 rc = iscsi_hdr_extract(tcp_conn);
872                 if (rc) {
873                        if (rc == -EAGAIN)
874                                 goto nomore;
875                        else {
876                                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
877                                 return 0;
878                        }
879                 }
880
881                 /*
882                  * Verify and process incoming PDU header.
883                  */
884                 rc = iscsi_tcp_hdr_recv(conn);
885                 if (!rc && tcp_conn->in.datalen) {
886                         if (conn->datadgst_en) {
887                                 crypto_hash_init(&tcp_conn->data_rx_hash);
888                         }
889                         tcp_conn->in_progress = IN_PROGRESS_DATA_RECV;
890                 } else if (rc) {
891                         iscsi_conn_failure(conn, rc);
892                         return 0;
893                 }
894         }
895
896         if (tcp_conn->in_progress == IN_PROGRESS_DDIGEST_RECV) {
897                 uint32_t recv_digest;
898
899                 debug_tcp("extra data_recv offset %d copy %d\n",
900                           tcp_conn->in.offset, tcp_conn->in.copy);
901                 skb_copy_bits(tcp_conn->in.skb, tcp_conn->in.offset,
902                                 &recv_digest, 4);
903                 tcp_conn->in.offset += 4;
904                 tcp_conn->in.copy -= 4;
905                 if (recv_digest != tcp_conn->in.datadgst) {
906                         debug_tcp("iscsi_tcp: data digest error!"
907                                   "0x%x != 0x%x\n", recv_digest,
908                                   tcp_conn->in.datadgst);
909                         iscsi_conn_failure(conn, ISCSI_ERR_DATA_DGST);
910                         return 0;
911                 } else {
912                         debug_tcp("iscsi_tcp: data digest match!"
913                                   "0x%x == 0x%x\n", recv_digest,
914                                   tcp_conn->in.datadgst);
915                         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
916                 }
917         }
918
919         if (tcp_conn->in_progress == IN_PROGRESS_DATA_RECV &&
920            tcp_conn->in.copy) {
921
922                 debug_tcp("data_recv offset %d copy %d\n",
923                        tcp_conn->in.offset, tcp_conn->in.copy);
924
925                 rc = iscsi_data_recv(conn);
926                 if (rc) {
927                         if (rc == -EAGAIN)
928                                 goto again;
929                         iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
930                         return 0;
931                 }
932                 tcp_conn->in.copy -= tcp_conn->in.padding;
933                 tcp_conn->in.offset += tcp_conn->in.padding;
934                 if (conn->datadgst_en) {
935                         if (tcp_conn->in.padding) {
936                                 debug_tcp("padding -> %d\n",
937                                           tcp_conn->in.padding);
938                                 memset(pad, 0, tcp_conn->in.padding);
939                                 sg_init_one(&sg, pad, tcp_conn->in.padding);
940                                 crypto_hash_update(&tcp_conn->data_rx_hash,
941                                                    &sg, sg.length);
942                         }
943                         crypto_hash_final(&tcp_conn->data_rx_hash,
944                                           (u8 *)&tcp_conn->in.datadgst);
945                         debug_tcp("rx digest 0x%x\n", tcp_conn->in.datadgst);
946                         tcp_conn->in_progress = IN_PROGRESS_DDIGEST_RECV;
947                 } else
948                         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
949         }
950
951         debug_tcp("f, processed %d from out of %d padding %d\n",
952                tcp_conn->in.offset - offset, (int)len, tcp_conn->in.padding);
953         BUG_ON(tcp_conn->in.offset - offset > len);
954
955         if (tcp_conn->in.offset - offset != len) {
956                 debug_tcp("continue to process %d bytes\n",
957                        (int)len - (tcp_conn->in.offset - offset));
958                 goto more;
959         }
960
961 nomore:
962         processed = tcp_conn->in.offset - offset;
963         BUG_ON(processed == 0);
964         return processed;
965
966 again:
967         processed = tcp_conn->in.offset - offset;
968         debug_tcp("c, processed %d from out of %d rd_desc_cnt %d\n",
969                   processed, (int)len, (int)rd_desc->count);
970         BUG_ON(processed == 0);
971         BUG_ON(processed > len);
972
973         conn->rxdata_octets += processed;
974         return processed;
975 }
976
977 static void
978 iscsi_tcp_data_ready(struct sock *sk, int flag)
979 {
980         struct iscsi_conn *conn = sk->sk_user_data;
981         read_descriptor_t rd_desc;
982
983         read_lock(&sk->sk_callback_lock);
984
985         /*
986          * Use rd_desc to pass 'conn' to iscsi_tcp_data_recv.
987          * We set count to 1 because we want the network layer to
988          * hand us all the skbs that are available. iscsi_tcp_data_recv
989          * handled pdus that cross buffers or pdus that still need data.
990          */
991         rd_desc.arg.data = conn;
992         rd_desc.count = 1;
993         tcp_read_sock(sk, &rd_desc, iscsi_tcp_data_recv);
994
995         read_unlock(&sk->sk_callback_lock);
996 }
997
998 static void
999 iscsi_tcp_state_change(struct sock *sk)
1000 {
1001         struct iscsi_tcp_conn *tcp_conn;
1002         struct iscsi_conn *conn;
1003         struct iscsi_session *session;
1004         void (*old_state_change)(struct sock *);
1005
1006         read_lock(&sk->sk_callback_lock);
1007
1008         conn = (struct iscsi_conn*)sk->sk_user_data;
1009         session = conn->session;
1010
1011         if ((sk->sk_state == TCP_CLOSE_WAIT ||
1012              sk->sk_state == TCP_CLOSE) &&
1013             !atomic_read(&sk->sk_rmem_alloc)) {
1014                 debug_tcp("iscsi_tcp_state_change: TCP_CLOSE|TCP_CLOSE_WAIT\n");
1015                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
1016         }
1017
1018         tcp_conn = conn->dd_data;
1019         old_state_change = tcp_conn->old_state_change;
1020
1021         read_unlock(&sk->sk_callback_lock);
1022
1023         old_state_change(sk);
1024 }
1025
1026 /**
1027  * iscsi_write_space - Called when more output buffer space is available
1028  * @sk: socket space is available for
1029  **/
1030 static void
1031 iscsi_write_space(struct sock *sk)
1032 {
1033         struct iscsi_conn *conn = (struct iscsi_conn*)sk->sk_user_data;
1034         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1035
1036         tcp_conn->old_write_space(sk);
1037         debug_tcp("iscsi_write_space: cid %d\n", conn->id);
1038         scsi_queue_work(conn->session->host, &conn->xmitwork);
1039 }
1040
1041 static void
1042 iscsi_conn_set_callbacks(struct iscsi_conn *conn)
1043 {
1044         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1045         struct sock *sk = tcp_conn->sock->sk;
1046
1047         /* assign new callbacks */
1048         write_lock_bh(&sk->sk_callback_lock);
1049         sk->sk_user_data = conn;
1050         tcp_conn->old_data_ready = sk->sk_data_ready;
1051         tcp_conn->old_state_change = sk->sk_state_change;
1052         tcp_conn->old_write_space = sk->sk_write_space;
1053         sk->sk_data_ready = iscsi_tcp_data_ready;
1054         sk->sk_state_change = iscsi_tcp_state_change;
1055         sk->sk_write_space = iscsi_write_space;
1056         write_unlock_bh(&sk->sk_callback_lock);
1057 }
1058
1059 static void
1060 iscsi_conn_restore_callbacks(struct iscsi_tcp_conn *tcp_conn)
1061 {
1062         struct sock *sk = tcp_conn->sock->sk;
1063
1064         /* restore socket callbacks, see also: iscsi_conn_set_callbacks() */
1065         write_lock_bh(&sk->sk_callback_lock);
1066         sk->sk_user_data    = NULL;
1067         sk->sk_data_ready   = tcp_conn->old_data_ready;
1068         sk->sk_state_change = tcp_conn->old_state_change;
1069         sk->sk_write_space  = tcp_conn->old_write_space;
1070         sk->sk_no_check  = 0;
1071         write_unlock_bh(&sk->sk_callback_lock);
1072 }
1073
1074 /**
1075  * iscsi_send - generic send routine
1076  * @sk: kernel's socket
1077  * @buf: buffer to write from
1078  * @size: actual size to write
1079  * @flags: socket's flags
1080  */
1081 static inline int
1082 iscsi_send(struct iscsi_conn *conn, struct iscsi_buf *buf, int size, int flags)
1083 {
1084         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1085         struct socket *sk = tcp_conn->sock;
1086         int offset = buf->sg.offset + buf->sent, res;
1087
1088         /*
1089          * if we got use_sg=0 or are sending something we kmallocd
1090          * then we did not have to do kmap (kmap returns page_address)
1091          *
1092          * if we got use_sg > 0, but had to drop down, we do not
1093          * set clustering so this should only happen for that
1094          * slab case.
1095          */
1096         if (buf->use_sendmsg)
1097                 res = sock_no_sendpage(sk, buf->sg.page, offset, size, flags);
1098         else
1099                 res = tcp_conn->sendpage(sk, buf->sg.page, offset, size, flags);
1100
1101         if (res >= 0) {
1102                 conn->txdata_octets += res;
1103                 buf->sent += res;
1104                 return res;
1105         }
1106
1107         tcp_conn->sendpage_failures_cnt++;
1108         if (res == -EAGAIN)
1109                 res = -ENOBUFS;
1110         else
1111                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
1112         return res;
1113 }
1114
1115 /**
1116  * iscsi_sendhdr - send PDU Header via tcp_sendpage()
1117  * @conn: iscsi connection
1118  * @buf: buffer to write from
1119  * @datalen: lenght of data to be sent after the header
1120  *
1121  * Notes:
1122  *      (Tx, Fast Path)
1123  **/
1124 static inline int
1125 iscsi_sendhdr(struct iscsi_conn *conn, struct iscsi_buf *buf, int datalen)
1126 {
1127         int flags = 0; /* MSG_DONTWAIT; */
1128         int res, size;
1129
1130         size = buf->sg.length - buf->sent;
1131         BUG_ON(buf->sent + size > buf->sg.length);
1132         if (buf->sent + size != buf->sg.length || datalen)
1133                 flags |= MSG_MORE;
1134
1135         res = iscsi_send(conn, buf, size, flags);
1136         debug_tcp("sendhdr %d bytes, sent %d res %d\n", size, buf->sent, res);
1137         if (res >= 0) {
1138                 if (size != res)
1139                         return -EAGAIN;
1140                 return 0;
1141         }
1142
1143         return res;
1144 }
1145
1146 /**
1147  * iscsi_sendpage - send one page of iSCSI Data-Out.
1148  * @conn: iscsi connection
1149  * @buf: buffer to write from
1150  * @count: remaining data
1151  * @sent: number of bytes sent
1152  *
1153  * Notes:
1154  *      (Tx, Fast Path)
1155  **/
1156 static inline int
1157 iscsi_sendpage(struct iscsi_conn *conn, struct iscsi_buf *buf,
1158                int *count, int *sent)
1159 {
1160         int flags = 0; /* MSG_DONTWAIT; */
1161         int res, size;
1162
1163         size = buf->sg.length - buf->sent;
1164         BUG_ON(buf->sent + size > buf->sg.length);
1165         if (size > *count)
1166                 size = *count;
1167         if (buf->sent + size != buf->sg.length || *count != size)
1168                 flags |= MSG_MORE;
1169
1170         res = iscsi_send(conn, buf, size, flags);
1171         debug_tcp("sendpage: %d bytes, sent %d left %d sent %d res %d\n",
1172                   size, buf->sent, *count, *sent, res);
1173         if (res >= 0) {
1174                 *count -= res;
1175                 *sent += res;
1176                 if (size != res)
1177                         return -EAGAIN;
1178                 return 0;
1179         }
1180
1181         return res;
1182 }
1183
1184 static inline void
1185 iscsi_data_digest_init(struct iscsi_tcp_conn *tcp_conn,
1186                       struct iscsi_cmd_task *ctask)
1187 {
1188         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1189
1190         crypto_hash_init(&tcp_conn->data_tx_hash);
1191         tcp_ctask->digest_count = 4;
1192 }
1193
1194 static int
1195 iscsi_digest_final_send(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
1196                         struct iscsi_buf *buf, uint32_t *digest, int final)
1197 {
1198         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1199         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1200         int rc = 0;
1201         int sent = 0;
1202
1203         if (final)
1204                 crypto_hash_final(&tcp_conn->data_tx_hash, (u8 *)digest);
1205
1206         iscsi_buf_init_iov(buf, (char*)digest, 4);
1207         rc = iscsi_sendpage(conn, buf, &tcp_ctask->digest_count, &sent);
1208         if (rc) {
1209                 tcp_ctask->datadigest = *digest;
1210                 tcp_ctask->xmstate |= XMSTATE_DATA_DIGEST;
1211         } else
1212                 tcp_ctask->digest_count = 4;
1213         return rc;
1214 }
1215
1216 /**
1217  * iscsi_solicit_data_cont - initialize next Data-Out
1218  * @conn: iscsi connection
1219  * @ctask: scsi command task
1220  * @r2t: R2T info
1221  * @left: bytes left to transfer
1222  *
1223  * Notes:
1224  *      Initialize next Data-Out within this R2T sequence and continue
1225  *      to process next Scatter-Gather element(if any) of this SCSI command.
1226  *
1227  *      Called under connection lock.
1228  **/
1229 static void
1230 iscsi_solicit_data_cont(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
1231                         struct iscsi_r2t_info *r2t, int left)
1232 {
1233         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1234         struct iscsi_data *hdr;
1235         struct scsi_cmnd *sc = ctask->sc;
1236         int new_offset;
1237
1238         hdr = &r2t->dtask.hdr;
1239         memset(hdr, 0, sizeof(struct iscsi_data));
1240         hdr->ttt = r2t->ttt;
1241         hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
1242         r2t->solicit_datasn++;
1243         hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
1244         memcpy(hdr->lun, ctask->hdr->lun, sizeof(hdr->lun));
1245         hdr->itt = ctask->hdr->itt;
1246         hdr->exp_statsn = r2t->exp_statsn;
1247         new_offset = r2t->data_offset + r2t->sent;
1248         hdr->offset = cpu_to_be32(new_offset);
1249         if (left > conn->max_xmit_dlength) {
1250                 hton24(hdr->dlength, conn->max_xmit_dlength);
1251                 r2t->data_count = conn->max_xmit_dlength;
1252         } else {
1253                 hton24(hdr->dlength, left);
1254                 r2t->data_count = left;
1255                 hdr->flags = ISCSI_FLAG_CMD_FINAL;
1256         }
1257         conn->dataout_pdus_cnt++;
1258
1259         iscsi_buf_init_iov(&r2t->headbuf, (char*)hdr,
1260                            sizeof(struct iscsi_hdr));
1261
1262         if (sc->use_sg && !iscsi_buf_left(&r2t->sendbuf)) {
1263                 BUG_ON(tcp_ctask->bad_sg == r2t->sg);
1264                 iscsi_buf_init_sg(&r2t->sendbuf, r2t->sg);
1265                 r2t->sg += 1;
1266         } else
1267                 iscsi_buf_init_iov(&tcp_ctask->sendbuf,
1268                             (char*)sc->request_buffer + new_offset,
1269                             r2t->data_count);
1270 }
1271
1272 static void
1273 iscsi_unsolicit_data_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1274 {
1275         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1276         struct iscsi_data_task *dtask;
1277
1278         dtask = tcp_ctask->dtask = &tcp_ctask->unsol_dtask;
1279         iscsi_prep_unsolicit_data_pdu(ctask, &dtask->hdr,
1280                                       tcp_ctask->r2t_data_count);
1281         iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)&dtask->hdr,
1282                            sizeof(struct iscsi_hdr));
1283 }
1284
1285 /**
1286  * iscsi_tcp_cmd_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
1287  * @conn: iscsi connection
1288  * @ctask: scsi command task
1289  * @sc: scsi command
1290  **/
1291 static void
1292 iscsi_tcp_cmd_init(struct iscsi_cmd_task *ctask)
1293 {
1294         struct scsi_cmnd *sc = ctask->sc;
1295         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1296
1297         BUG_ON(__kfifo_len(tcp_ctask->r2tqueue));
1298
1299         tcp_ctask->sent = 0;
1300         tcp_ctask->sg_count = 0;
1301
1302         if (sc->sc_data_direction == DMA_TO_DEVICE) {
1303                 tcp_ctask->xmstate = XMSTATE_W_HDR;
1304                 tcp_ctask->exp_r2tsn = 0;
1305                 BUG_ON(ctask->total_length == 0);
1306
1307                 if (sc->use_sg) {
1308                         struct scatterlist *sg = sc->request_buffer;
1309
1310                         iscsi_buf_init_sg(&tcp_ctask->sendbuf,
1311                                           &sg[tcp_ctask->sg_count++]);
1312                         tcp_ctask->sg = sg;
1313                         tcp_ctask->bad_sg = sg + sc->use_sg;
1314                 } else
1315                         iscsi_buf_init_iov(&tcp_ctask->sendbuf,
1316                                            sc->request_buffer,
1317                                            sc->request_bufflen);
1318
1319                 if (ctask->imm_count)
1320                         tcp_ctask->xmstate |= XMSTATE_IMM_DATA;
1321
1322                 tcp_ctask->pad_count = ctask->total_length & (ISCSI_PAD_LEN-1);
1323                 if (tcp_ctask->pad_count) {
1324                         tcp_ctask->pad_count = ISCSI_PAD_LEN -
1325                                                         tcp_ctask->pad_count;
1326                         debug_scsi("write padding %d bytes\n",
1327                                    tcp_ctask->pad_count);
1328                         tcp_ctask->xmstate |= XMSTATE_W_PAD;
1329                 }
1330
1331                 if (ctask->unsol_count)
1332                         tcp_ctask->xmstate |= XMSTATE_UNS_HDR |
1333                                                 XMSTATE_UNS_INIT;
1334                 tcp_ctask->r2t_data_count = ctask->total_length -
1335                                     ctask->imm_count -
1336                                     ctask->unsol_count;
1337
1338                 debug_scsi("cmd [itt 0x%x total %d imm %d imm_data %d "
1339                            "r2t_data %d]\n",
1340                            ctask->itt, ctask->total_length, ctask->imm_count,
1341                            ctask->unsol_count, tcp_ctask->r2t_data_count);
1342         } else
1343                 tcp_ctask->xmstate = XMSTATE_R_HDR;
1344
1345         iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)ctask->hdr,
1346                             sizeof(struct iscsi_hdr));
1347 }
1348
1349 /**
1350  * iscsi_tcp_mtask_xmit - xmit management(immediate) task
1351  * @conn: iscsi connection
1352  * @mtask: task management task
1353  *
1354  * Notes:
1355  *      The function can return -EAGAIN in which case caller must
1356  *      call it again later, or recover. '0' return code means successful
1357  *      xmit.
1358  *
1359  *      Management xmit state machine consists of two states:
1360  *              IN_PROGRESS_IMM_HEAD - PDU Header xmit in progress
1361  *              IN_PROGRESS_IMM_DATA - PDU Data xmit in progress
1362  **/
1363 static int
1364 iscsi_tcp_mtask_xmit(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask)
1365 {
1366         struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;
1367         int rc;
1368
1369         debug_scsi("mtask deq [cid %d state %x itt 0x%x]\n",
1370                 conn->id, tcp_mtask->xmstate, mtask->itt);
1371
1372         if (tcp_mtask->xmstate & XMSTATE_IMM_HDR) {
1373                 tcp_mtask->xmstate &= ~XMSTATE_IMM_HDR;
1374                 if (mtask->data_count)
1375                         tcp_mtask->xmstate |= XMSTATE_IMM_DATA;
1376                 if (conn->c_stage != ISCSI_CONN_INITIAL_STAGE &&
1377                     conn->stop_stage != STOP_CONN_RECOVER &&
1378                     conn->hdrdgst_en)
1379                         iscsi_hdr_digest(conn, &tcp_mtask->headbuf,
1380                                         (u8*)tcp_mtask->hdrext);
1381                 rc = iscsi_sendhdr(conn, &tcp_mtask->headbuf,
1382                                    mtask->data_count);
1383                 if (rc) {
1384                         tcp_mtask->xmstate |= XMSTATE_IMM_HDR;
1385                         if (mtask->data_count)
1386                                 tcp_mtask->xmstate &= ~XMSTATE_IMM_DATA;
1387                         return rc;
1388                 }
1389         }
1390
1391         if (tcp_mtask->xmstate & XMSTATE_IMM_DATA) {
1392                 BUG_ON(!mtask->data_count);
1393                 tcp_mtask->xmstate &= ~XMSTATE_IMM_DATA;
1394                 /* FIXME: implement.
1395                  * Virtual buffer could be spreaded across multiple pages...
1396                  */
1397                 do {
1398                         int rc;
1399
1400                         rc = iscsi_sendpage(conn, &tcp_mtask->sendbuf,
1401                                         &mtask->data_count, &tcp_mtask->sent);
1402                         if (rc) {
1403                                 tcp_mtask->xmstate |= XMSTATE_IMM_DATA;
1404                                 return rc;
1405                         }
1406                 } while (mtask->data_count);
1407         }
1408
1409         BUG_ON(tcp_mtask->xmstate != XMSTATE_IDLE);
1410         if (mtask->hdr->itt == cpu_to_be32(ISCSI_RESERVED_TAG)) {
1411                 struct iscsi_session *session = conn->session;
1412
1413                 spin_lock_bh(&session->lock);
1414                 list_del(&conn->mtask->running);
1415                 __kfifo_put(session->mgmtpool.queue, (void*)&conn->mtask,
1416                             sizeof(void*));
1417                 spin_unlock_bh(&session->lock);
1418         }
1419         return 0;
1420 }
1421
1422 static inline int
1423 handle_xmstate_r_hdr(struct iscsi_conn *conn,
1424                      struct iscsi_tcp_cmd_task *tcp_ctask)
1425 {
1426         int rc;
1427
1428         tcp_ctask->xmstate &= ~XMSTATE_R_HDR;
1429         if (conn->hdrdgst_en)
1430                 iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
1431                                  (u8*)tcp_ctask->hdrext);
1432         rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, 0);
1433         if (!rc) {
1434                 BUG_ON(tcp_ctask->xmstate != XMSTATE_IDLE);
1435                 return 0; /* wait for Data-In */
1436         }
1437         tcp_ctask->xmstate |= XMSTATE_R_HDR;
1438         return rc;
1439 }
1440
1441 static inline int
1442 handle_xmstate_w_hdr(struct iscsi_conn *conn,
1443                      struct iscsi_cmd_task *ctask)
1444 {
1445         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1446         int rc;
1447
1448         tcp_ctask->xmstate &= ~XMSTATE_W_HDR;
1449         if (conn->hdrdgst_en)
1450                 iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
1451                                  (u8*)tcp_ctask->hdrext);
1452         rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->imm_count);
1453         if (rc)
1454                 tcp_ctask->xmstate |= XMSTATE_W_HDR;
1455         return rc;
1456 }
1457
1458 static inline int
1459 handle_xmstate_data_digest(struct iscsi_conn *conn,
1460                            struct iscsi_cmd_task *ctask)
1461 {
1462         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1463         int rc;
1464
1465         tcp_ctask->xmstate &= ~XMSTATE_DATA_DIGEST;
1466         debug_tcp("resent data digest 0x%x\n", tcp_ctask->datadigest);
1467         rc = iscsi_digest_final_send(conn, ctask, &tcp_ctask->immbuf,
1468                                     &tcp_ctask->datadigest, 0);
1469         if (rc) {
1470                 tcp_ctask->xmstate |= XMSTATE_DATA_DIGEST;
1471                 debug_tcp("resent data digest 0x%x fail!\n",
1472                           tcp_ctask->datadigest);
1473         }
1474
1475         return rc;
1476 }
1477
1478 static inline int
1479 handle_xmstate_imm_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1480 {
1481         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1482         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1483         int rc;
1484
1485         BUG_ON(!ctask->imm_count);
1486         tcp_ctask->xmstate &= ~XMSTATE_IMM_DATA;
1487
1488         if (conn->datadgst_en) {
1489                 iscsi_data_digest_init(tcp_conn, ctask);
1490                 tcp_ctask->immdigest = 0;
1491         }
1492
1493         for (;;) {
1494                 rc = iscsi_sendpage(conn, &tcp_ctask->sendbuf,
1495                                    &ctask->imm_count, &tcp_ctask->sent);
1496                 if (rc) {
1497                         tcp_ctask->xmstate |= XMSTATE_IMM_DATA;
1498                         if (conn->datadgst_en) {
1499                                 crypto_hash_final(&tcp_conn->data_tx_hash,
1500                                                   (u8 *)&tcp_ctask->immdigest);
1501                                 debug_tcp("tx imm sendpage fail 0x%x\n",
1502                                           tcp_ctask->datadigest);
1503                         }
1504                         return rc;
1505                 }
1506                 if (conn->datadgst_en)
1507                         crypto_hash_update(&tcp_conn->data_tx_hash,
1508                                            &tcp_ctask->sendbuf.sg,
1509                                            tcp_ctask->sendbuf.sg.length);
1510
1511                 if (!ctask->imm_count)
1512                         break;
1513                 iscsi_buf_init_sg(&tcp_ctask->sendbuf,
1514                                   &tcp_ctask->sg[tcp_ctask->sg_count++]);
1515         }
1516
1517         if (conn->datadgst_en && !(tcp_ctask->xmstate & XMSTATE_W_PAD)) {
1518                 rc = iscsi_digest_final_send(conn, ctask, &tcp_ctask->immbuf,
1519                                             &tcp_ctask->immdigest, 1);
1520                 if (rc) {
1521                         debug_tcp("sending imm digest 0x%x fail!\n",
1522                                   tcp_ctask->immdigest);
1523                         return rc;
1524                 }
1525                 debug_tcp("sending imm digest 0x%x\n", tcp_ctask->immdigest);
1526         }
1527
1528         return 0;
1529 }
1530
1531 static inline int
1532 handle_xmstate_uns_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1533 {
1534         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1535         struct iscsi_data_task *dtask;
1536         int rc;
1537
1538         tcp_ctask->xmstate |= XMSTATE_UNS_DATA;
1539         if (tcp_ctask->xmstate & XMSTATE_UNS_INIT) {
1540                 iscsi_unsolicit_data_init(conn, ctask);
1541                 dtask = tcp_ctask->dtask;
1542                 if (conn->hdrdgst_en)
1543                         iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
1544                                         (u8*)dtask->hdrext);
1545                 tcp_ctask->xmstate &= ~XMSTATE_UNS_INIT;
1546         }
1547
1548         rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->data_count);
1549         if (rc) {
1550                 tcp_ctask->xmstate &= ~XMSTATE_UNS_DATA;
1551                 tcp_ctask->xmstate |= XMSTATE_UNS_HDR;
1552                 return rc;
1553         }
1554
1555         debug_scsi("uns dout [itt 0x%x dlen %d sent %d]\n",
1556                    ctask->itt, ctask->unsol_count, tcp_ctask->sent);
1557         return 0;
1558 }
1559
1560 static inline int
1561 handle_xmstate_uns_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1562 {
1563         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1564         struct iscsi_data_task *dtask = tcp_ctask->dtask;
1565         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1566         int rc;
1567
1568         BUG_ON(!ctask->data_count);
1569         tcp_ctask->xmstate &= ~XMSTATE_UNS_DATA;
1570
1571         if (conn->datadgst_en) {
1572                 iscsi_data_digest_init(tcp_conn, ctask);
1573                 dtask->digest = 0;
1574         }
1575
1576         for (;;) {
1577                 int start = tcp_ctask->sent;
1578
1579                 rc = iscsi_sendpage(conn, &tcp_ctask->sendbuf,
1580                                    &ctask->data_count, &tcp_ctask->sent);
1581                 if (rc) {
1582                         ctask->unsol_count -= tcp_ctask->sent - start;
1583                         tcp_ctask->xmstate |= XMSTATE_UNS_DATA;
1584                         /* will continue with this ctask later.. */
1585                         if (conn->datadgst_en) {
1586                                 crypto_hash_final(&tcp_conn->data_tx_hash,
1587                                                   (u8 *)&dtask->digest);
1588                                 debug_tcp("tx uns data fail 0x%x\n",
1589                                           dtask->digest);
1590                         }
1591                         return rc;
1592                 }
1593
1594                 BUG_ON(tcp_ctask->sent > ctask->total_length);
1595                 ctask->unsol_count -= tcp_ctask->sent - start;
1596
1597                 /*
1598                  * XXX:we may run here with un-initial sendbuf.
1599                  * so pass it
1600                  */
1601                 if (conn->datadgst_en && tcp_ctask->sent - start > 0)
1602                         crypto_hash_update(&tcp_conn->data_tx_hash,
1603                                            &tcp_ctask->sendbuf.sg,
1604                                            tcp_ctask->sendbuf.sg.length);
1605
1606                 if (!ctask->data_count)
1607                         break;
1608                 iscsi_buf_init_sg(&tcp_ctask->sendbuf,
1609                                   &tcp_ctask->sg[tcp_ctask->sg_count++]);
1610         }
1611         BUG_ON(ctask->unsol_count < 0);
1612
1613         /*
1614          * Done with the Data-Out. Next, check if we need
1615          * to send another unsolicited Data-Out.
1616          */
1617         if (ctask->unsol_count) {
1618                 if (conn->datadgst_en) {
1619                         rc = iscsi_digest_final_send(conn, ctask,
1620                                                     &dtask->digestbuf,
1621                                                     &dtask->digest, 1);
1622                         if (rc) {
1623                                 debug_tcp("send uns digest 0x%x fail\n",
1624                                           dtask->digest);
1625                                 return rc;
1626                         }
1627                         debug_tcp("sending uns digest 0x%x, more uns\n",
1628                                   dtask->digest);
1629                 }
1630                 tcp_ctask->xmstate |= XMSTATE_UNS_INIT;
1631                 return 1;
1632         }
1633
1634         if (conn->datadgst_en && !(tcp_ctask->xmstate & XMSTATE_W_PAD)) {
1635                 rc = iscsi_digest_final_send(conn, ctask,
1636                                             &dtask->digestbuf,
1637                                             &dtask->digest, 1);
1638                 if (rc) {
1639                         debug_tcp("send last uns digest 0x%x fail\n",
1640                                    dtask->digest);
1641                         return rc;
1642                 }
1643                 debug_tcp("sending uns digest 0x%x\n",dtask->digest);
1644         }
1645
1646         return 0;
1647 }
1648
1649 static inline int
1650 handle_xmstate_sol_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1651 {
1652         struct iscsi_session *session = conn->session;
1653         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1654         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1655         struct iscsi_r2t_info *r2t = tcp_ctask->r2t;
1656         struct iscsi_data_task *dtask = &r2t->dtask;
1657         int left, rc;
1658
1659         tcp_ctask->xmstate &= ~XMSTATE_SOL_DATA;
1660         tcp_ctask->dtask = dtask;
1661
1662         if (conn->datadgst_en) {
1663                 iscsi_data_digest_init(tcp_conn, ctask);
1664                 dtask->digest = 0;
1665         }
1666 solicit_again:
1667         /*
1668          * send Data-Out within this R2T sequence.
1669          */
1670         if (!r2t->data_count)
1671                 goto data_out_done;
1672
1673         rc = iscsi_sendpage(conn, &r2t->sendbuf, &r2t->data_count, &r2t->sent);
1674         if (rc) {
1675                 tcp_ctask->xmstate |= XMSTATE_SOL_DATA;
1676                 /* will continue with this ctask later.. */
1677                 if (conn->datadgst_en) {
1678                         crypto_hash_final(&tcp_conn->data_tx_hash,
1679                                           (u8 *)&dtask->digest);
1680                         debug_tcp("r2t data send fail 0x%x\n", dtask->digest);
1681                 }
1682                 return rc;
1683         }
1684
1685         BUG_ON(r2t->data_count < 0);
1686         if (conn->datadgst_en)
1687                 crypto_hash_update(&tcp_conn->data_tx_hash, &r2t->sendbuf.sg,
1688                                    r2t->sendbuf.sg.length);
1689
1690         if (r2t->data_count) {
1691                 BUG_ON(ctask->sc->use_sg == 0);
1692                 if (!iscsi_buf_left(&r2t->sendbuf)) {
1693                         BUG_ON(tcp_ctask->bad_sg == r2t->sg);
1694                         iscsi_buf_init_sg(&r2t->sendbuf, r2t->sg);
1695                         r2t->sg += 1;
1696                 }
1697                 goto solicit_again;
1698         }
1699
1700 data_out_done:
1701         /*
1702          * Done with this Data-Out. Next, check if we have
1703          * to send another Data-Out for this R2T.
1704          */
1705         BUG_ON(r2t->data_length - r2t->sent < 0);
1706         left = r2t->data_length - r2t->sent;
1707         if (left) {
1708                 if (conn->datadgst_en) {
1709                         rc = iscsi_digest_final_send(conn, ctask,
1710                                                     &dtask->digestbuf,
1711                                                     &dtask->digest, 1);
1712                         if (rc) {
1713                                 debug_tcp("send r2t data digest 0x%x"
1714                                           "fail\n", dtask->digest);
1715                                 return rc;
1716                         }
1717                         debug_tcp("r2t data send digest 0x%x\n",
1718                                   dtask->digest);
1719                 }
1720                 iscsi_solicit_data_cont(conn, ctask, r2t, left);
1721                 tcp_ctask->xmstate |= XMSTATE_SOL_DATA;
1722                 tcp_ctask->xmstate &= ~XMSTATE_SOL_HDR;
1723                 return 1;
1724         }
1725
1726         /*
1727          * Done with this R2T. Check if there are more
1728          * outstanding R2Ts ready to be processed.
1729          */
1730         BUG_ON(tcp_ctask->r2t_data_count - r2t->data_length < 0);
1731         if (conn->datadgst_en) {
1732                 rc = iscsi_digest_final_send(conn, ctask, &dtask->digestbuf,
1733                                             &dtask->digest, 1);
1734                 if (rc) {
1735                         debug_tcp("send last r2t data digest 0x%x"
1736                                   "fail\n", dtask->digest);
1737                         return rc;
1738                 }
1739                 debug_tcp("r2t done dout digest 0x%x\n", dtask->digest);
1740         }
1741
1742         tcp_ctask->r2t_data_count -= r2t->data_length;
1743         tcp_ctask->r2t = NULL;
1744         spin_lock_bh(&session->lock);
1745         __kfifo_put(tcp_ctask->r2tpool.queue, (void*)&r2t, sizeof(void*));
1746         spin_unlock_bh(&session->lock);
1747         if (__kfifo_get(tcp_ctask->r2tqueue, (void*)&r2t, sizeof(void*))) {
1748                 tcp_ctask->r2t = r2t;
1749                 tcp_ctask->xmstate |= XMSTATE_SOL_DATA;
1750                 tcp_ctask->xmstate &= ~XMSTATE_SOL_HDR;
1751                 return 1;
1752         }
1753
1754         return 0;
1755 }
1756
1757 static inline int
1758 handle_xmstate_w_pad(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1759 {
1760         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1761         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1762         struct iscsi_data_task *dtask = tcp_ctask->dtask;
1763         int sent = 0, rc;
1764
1765         tcp_ctask->xmstate &= ~XMSTATE_W_PAD;
1766         iscsi_buf_init_iov(&tcp_ctask->sendbuf, (char*)&tcp_ctask->pad,
1767                             tcp_ctask->pad_count);
1768         rc = iscsi_sendpage(conn, &tcp_ctask->sendbuf, &tcp_ctask->pad_count,
1769                            &sent);
1770         if (rc) {
1771                 tcp_ctask->xmstate |= XMSTATE_W_PAD;
1772                 return rc;
1773         }
1774
1775         if (conn->datadgst_en) {
1776                 crypto_hash_update(&tcp_conn->data_tx_hash,
1777                                    &tcp_ctask->sendbuf.sg,
1778                                    tcp_ctask->sendbuf.sg.length);
1779                 /* imm data? */
1780                 if (!dtask) {
1781                         rc = iscsi_digest_final_send(conn, ctask,
1782                                                     &tcp_ctask->immbuf,
1783                                                     &tcp_ctask->immdigest, 1);
1784                         if (rc) {
1785                                 debug_tcp("send padding digest 0x%x"
1786                                           "fail!\n", tcp_ctask->immdigest);
1787                                 return rc;
1788                         }
1789                         debug_tcp("done with padding, digest 0x%x\n",
1790                                   tcp_ctask->datadigest);
1791                 } else {
1792                         rc = iscsi_digest_final_send(conn, ctask,
1793                                                     &dtask->digestbuf,
1794                                                     &dtask->digest, 1);
1795                         if (rc) {
1796                                 debug_tcp("send padding digest 0x%x"
1797                                           "fail\n", dtask->digest);
1798                                 return rc;
1799                         }
1800                         debug_tcp("done with padding, digest 0x%x\n",
1801                                   dtask->digest);
1802                 }
1803         }
1804
1805         return 0;
1806 }
1807
1808 static int
1809 iscsi_tcp_ctask_xmit(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1810 {
1811         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1812         int rc = 0;
1813
1814         debug_scsi("ctask deq [cid %d xmstate %x itt 0x%x]\n",
1815                 conn->id, tcp_ctask->xmstate, ctask->itt);
1816
1817         /*
1818          * serialize with TMF AbortTask
1819          */
1820         if (ctask->mtask)
1821                 return rc;
1822
1823         if (tcp_ctask->xmstate & XMSTATE_R_HDR)
1824                 return handle_xmstate_r_hdr(conn, tcp_ctask);
1825
1826         if (tcp_ctask->xmstate & XMSTATE_W_HDR) {
1827                 rc = handle_xmstate_w_hdr(conn, ctask);
1828                 if (rc)
1829                         return rc;
1830         }
1831
1832         /* XXX: for data digest xmit recover */
1833         if (tcp_ctask->xmstate & XMSTATE_DATA_DIGEST) {
1834                 rc = handle_xmstate_data_digest(conn, ctask);
1835                 if (rc)
1836                         return rc;
1837         }
1838
1839         if (tcp_ctask->xmstate & XMSTATE_IMM_DATA) {
1840                 rc = handle_xmstate_imm_data(conn, ctask);
1841                 if (rc)
1842                         return rc;
1843         }
1844
1845         if (tcp_ctask->xmstate & XMSTATE_UNS_HDR) {
1846                 BUG_ON(!ctask->unsol_count);
1847                 tcp_ctask->xmstate &= ~XMSTATE_UNS_HDR;
1848 unsolicit_head_again:
1849                 rc = handle_xmstate_uns_hdr(conn, ctask);
1850                 if (rc)
1851                         return rc;
1852         }
1853
1854         if (tcp_ctask->xmstate & XMSTATE_UNS_DATA) {
1855                 rc = handle_xmstate_uns_data(conn, ctask);
1856                 if (rc == 1)
1857                         goto unsolicit_head_again;
1858                 else if (rc)
1859                         return rc;
1860                 goto done;
1861         }
1862
1863         if (tcp_ctask->xmstate & XMSTATE_SOL_HDR) {
1864                 struct iscsi_r2t_info *r2t;
1865
1866                 tcp_ctask->xmstate &= ~XMSTATE_SOL_HDR;
1867                 tcp_ctask->xmstate |= XMSTATE_SOL_DATA;
1868                 if (!tcp_ctask->r2t)
1869                         __kfifo_get(tcp_ctask->r2tqueue, (void*)&tcp_ctask->r2t,
1870                                     sizeof(void*));
1871 solicit_head_again:
1872                 r2t = tcp_ctask->r2t;
1873                 if (conn->hdrdgst_en)
1874                         iscsi_hdr_digest(conn, &r2t->headbuf,
1875                                         (u8*)r2t->dtask.hdrext);
1876                 rc = iscsi_sendhdr(conn, &r2t->headbuf, r2t->data_count);
1877                 if (rc) {
1878                         tcp_ctask->xmstate &= ~XMSTATE_SOL_DATA;
1879                         tcp_ctask->xmstate |= XMSTATE_SOL_HDR;
1880                         return rc;
1881                 }
1882
1883                 debug_scsi("sol dout [dsn %d itt 0x%x dlen %d sent %d]\n",
1884                         r2t->solicit_datasn - 1, ctask->itt, r2t->data_count,
1885                         r2t->sent);
1886         }
1887
1888         if (tcp_ctask->xmstate & XMSTATE_SOL_DATA) {
1889                 rc = handle_xmstate_sol_data(conn, ctask);
1890                 if (rc == 1)
1891                         goto solicit_head_again;
1892                 if (rc)
1893                         return rc;
1894         }
1895
1896 done:
1897         /*
1898          * Last thing to check is whether we need to send write
1899          * padding. Note that we check for xmstate equality, not just the bit.
1900          */
1901         if (tcp_ctask->xmstate == XMSTATE_W_PAD)
1902                 rc = handle_xmstate_w_pad(conn, ctask);
1903
1904         return rc;
1905 }
1906
1907 static struct iscsi_cls_conn *
1908 iscsi_tcp_conn_create(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
1909 {
1910         struct iscsi_conn *conn;
1911         struct iscsi_cls_conn *cls_conn;
1912         struct iscsi_tcp_conn *tcp_conn;
1913
1914         cls_conn = iscsi_conn_setup(cls_session, conn_idx);
1915         if (!cls_conn)
1916                 return NULL;
1917         conn = cls_conn->dd_data;
1918         /*
1919          * due to strange issues with iser these are not set
1920          * in iscsi_conn_setup
1921          */
1922         conn->max_recv_dlength = DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH;
1923
1924         tcp_conn = kzalloc(sizeof(*tcp_conn), GFP_KERNEL);
1925         if (!tcp_conn)
1926                 goto tcp_conn_alloc_fail;
1927
1928         conn->dd_data = tcp_conn;
1929         tcp_conn->iscsi_conn = conn;
1930         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
1931         /* initial operational parameters */
1932         tcp_conn->hdr_size = sizeof(struct iscsi_hdr);
1933
1934         return cls_conn;
1935
1936 tcp_conn_alloc_fail:
1937         iscsi_conn_teardown(cls_conn);
1938         return NULL;
1939 }
1940
1941 static void
1942 iscsi_tcp_release_conn(struct iscsi_conn *conn)
1943 {
1944         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1945
1946         if (!tcp_conn->sock)
1947                 return;
1948
1949         sock_hold(tcp_conn->sock->sk);
1950         iscsi_conn_restore_callbacks(tcp_conn);
1951         sock_put(tcp_conn->sock->sk);
1952
1953         sock_release(tcp_conn->sock);
1954         tcp_conn->sock = NULL;
1955         conn->recv_lock = NULL;
1956 }
1957
1958 static void
1959 iscsi_tcp_conn_destroy(struct iscsi_cls_conn *cls_conn)
1960 {
1961         struct iscsi_conn *conn = cls_conn->dd_data;
1962         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1963         int digest = 0;
1964
1965         if (conn->hdrdgst_en || conn->datadgst_en)
1966                 digest = 1;
1967
1968         iscsi_tcp_release_conn(conn);
1969         iscsi_conn_teardown(cls_conn);
1970
1971         /* now free tcp_conn */
1972         if (digest) {
1973                 if (tcp_conn->tx_tfm)
1974                         crypto_free_hash(tcp_conn->tx_tfm);
1975                 if (tcp_conn->rx_tfm)
1976                         crypto_free_hash(tcp_conn->rx_tfm);
1977                 if (tcp_conn->data_tx_hash.tfm)
1978                         crypto_free_hash(tcp_conn->data_tx_hash.tfm);
1979                 if (tcp_conn->data_rx_hash.tfm)
1980                         crypto_free_hash(tcp_conn->data_rx_hash.tfm);
1981         }
1982
1983         kfree(tcp_conn);
1984 }
1985
1986 static void
1987 iscsi_tcp_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
1988 {
1989         struct iscsi_conn *conn = cls_conn->dd_data;
1990
1991         iscsi_conn_stop(cls_conn, flag);
1992         iscsi_tcp_release_conn(conn);
1993 }
1994
1995 static int
1996 iscsi_tcp_conn_bind(struct iscsi_cls_session *cls_session,
1997                     struct iscsi_cls_conn *cls_conn, uint64_t transport_eph,
1998                     int is_leading)
1999 {
2000         struct iscsi_conn *conn = cls_conn->dd_data;
2001         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
2002         struct sock *sk;
2003         struct socket *sock;
2004         int err;
2005
2006         /* lookup for existing socket */
2007         sock = sockfd_lookup((int)transport_eph, &err);
2008         if (!sock) {
2009                 printk(KERN_ERR "iscsi_tcp: sockfd_lookup failed %d\n", err);
2010                 return -EEXIST;
2011         }
2012
2013         err = iscsi_conn_bind(cls_session, cls_conn, is_leading);
2014         if (err)
2015                 return err;
2016
2017         /* bind iSCSI connection and socket */
2018         tcp_conn->sock = sock;
2019
2020         /* setup Socket parameters */
2021         sk = sock->sk;
2022         sk->sk_reuse = 1;
2023         sk->sk_sndtimeo = 15 * HZ; /* FIXME: make it configurable */
2024         sk->sk_allocation = GFP_ATOMIC;
2025
2026         /* FIXME: disable Nagle's algorithm */
2027
2028         /*
2029          * Intercept TCP callbacks for sendfile like receive
2030          * processing.
2031          */
2032         conn->recv_lock = &sk->sk_callback_lock;
2033         iscsi_conn_set_callbacks(conn);
2034         tcp_conn->sendpage = tcp_conn->sock->ops->sendpage;
2035         /*
2036          * set receive state machine into initial state
2037          */
2038         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
2039
2040         return 0;
2041 }
2042
2043 /* called with host lock */
2044 static void
2045 iscsi_tcp_mgmt_init(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask,
2046                     char *data, uint32_t data_size)
2047 {
2048         struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;
2049
2050         iscsi_buf_init_iov(&tcp_mtask->headbuf, (char*)mtask->hdr,
2051                            sizeof(struct iscsi_hdr));
2052         tcp_mtask->xmstate = XMSTATE_IMM_HDR;
2053         tcp_mtask->sent = 0;
2054
2055         if (mtask->data_count)
2056                 iscsi_buf_init_iov(&tcp_mtask->sendbuf, (char*)mtask->data,
2057                                     mtask->data_count);
2058 }
2059
2060 static int
2061 iscsi_r2tpool_alloc(struct iscsi_session *session)
2062 {
2063         int i;
2064         int cmd_i;
2065
2066         /*
2067          * initialize per-task: R2T pool and xmit queue
2068          */
2069         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
2070                 struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
2071                 struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
2072
2073                 /*
2074                  * pre-allocated x4 as much r2ts to handle race when
2075                  * target acks DataOut faster than we data_xmit() queues
2076                  * could replenish r2tqueue.
2077                  */
2078
2079                 /* R2T pool */
2080                 if (iscsi_pool_init(&tcp_ctask->r2tpool, session->max_r2t * 4,
2081                                     (void***)&tcp_ctask->r2ts,
2082                                     sizeof(struct iscsi_r2t_info))) {
2083                         goto r2t_alloc_fail;
2084                 }
2085
2086                 /* R2T xmit queue */
2087                 tcp_ctask->r2tqueue = kfifo_alloc(
2088                       session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL);
2089                 if (tcp_ctask->r2tqueue == ERR_PTR(-ENOMEM)) {
2090                         iscsi_pool_free(&tcp_ctask->r2tpool,
2091                                         (void**)tcp_ctask->r2ts);
2092                         goto r2t_alloc_fail;
2093                 }
2094         }
2095
2096         return 0;
2097
2098 r2t_alloc_fail:
2099         for (i = 0; i < cmd_i; i++) {
2100                 struct iscsi_cmd_task *ctask = session->cmds[i];
2101                 struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
2102
2103                 kfifo_free(tcp_ctask->r2tqueue);
2104                 iscsi_pool_free(&tcp_ctask->r2tpool,
2105                                 (void**)tcp_ctask->r2ts);
2106         }
2107         return -ENOMEM;
2108 }
2109
2110 static void
2111 iscsi_r2tpool_free(struct iscsi_session *session)
2112 {
2113         int i;
2114
2115         for (i = 0; i < session->cmds_max; i++) {
2116                 struct iscsi_cmd_task *ctask = session->cmds[i];
2117                 struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
2118
2119                 kfifo_free(tcp_ctask->r2tqueue);
2120                 iscsi_pool_free(&tcp_ctask->r2tpool,
2121                                 (void**)tcp_ctask->r2ts);
2122         }
2123 }
2124
2125 static int
2126 iscsi_conn_set_param(struct iscsi_cls_conn *cls_conn, enum iscsi_param param,
2127                      char *buf, int buflen)
2128 {
2129         struct iscsi_conn *conn = cls_conn->dd_data;
2130         struct iscsi_session *session = conn->session;
2131         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
2132         int value;
2133
2134         switch(param) {
2135         case ISCSI_PARAM_HDRDGST_EN:
2136                 iscsi_set_param(cls_conn, param, buf, buflen);
2137                 tcp_conn->hdr_size = sizeof(struct iscsi_hdr);
2138                 if (conn->hdrdgst_en) {
2139                         tcp_conn->hdr_size += sizeof(__u32);
2140                         if (!tcp_conn->tx_tfm)
2141                                 tcp_conn->tx_tfm =
2142                                         crypto_alloc_hash("crc32c", 0,
2143                                                           CRYPTO_ALG_ASYNC);
2144                         if (IS_ERR(tcp_conn->tx_tfm))
2145                                 return PTR_ERR(tcp_conn->tx_tfm);
2146                         if (!tcp_conn->rx_tfm)
2147                                 tcp_conn->rx_tfm =
2148                                         crypto_alloc_hash("crc32c", 0,
2149                                                           CRYPTO_ALG_ASYNC);
2150                         if (IS_ERR(tcp_conn->rx_tfm)) {
2151                                 crypto_free_hash(tcp_conn->tx_tfm);
2152                                 return PTR_ERR(tcp_conn->rx_tfm);
2153                         }
2154                 } else {
2155                         if (tcp_conn->tx_tfm)
2156                                 crypto_free_hash(tcp_conn->tx_tfm);
2157                         if (tcp_conn->rx_tfm)
2158                                 crypto_free_hash(tcp_conn->rx_tfm);
2159                 }
2160                 break;
2161         case ISCSI_PARAM_DATADGST_EN:
2162                 iscsi_set_param(cls_conn, param, buf, buflen);
2163                 if (conn->datadgst_en) {
2164                         if (!tcp_conn->data_tx_hash.tfm)
2165                                 tcp_conn->data_tx_hash.tfm =
2166                                     crypto_alloc_hash("crc32c", 0,
2167                                                       CRYPTO_ALG_ASYNC);
2168                         if (IS_ERR(tcp_conn->data_tx_hash.tfm))
2169                                 return PTR_ERR(tcp_conn->data_tx_hash.tfm);
2170                         if (!tcp_conn->data_rx_hash.tfm)
2171                                 tcp_conn->data_rx_hash.tfm =
2172                                     crypto_alloc_hash("crc32c", 0,
2173                                                       CRYPTO_ALG_ASYNC);
2174                         if (IS_ERR(tcp_conn->data_rx_hash.tfm)) {
2175                                 crypto_free_hash(tcp_conn->data_tx_hash.tfm);
2176                                 return PTR_ERR(tcp_conn->data_rx_hash.tfm);
2177                         }
2178                 } else {
2179                         if (tcp_conn->data_tx_hash.tfm)
2180                                 crypto_free_hash(tcp_conn->data_tx_hash.tfm);
2181                         if (tcp_conn->data_rx_hash.tfm)
2182                                 crypto_free_hash(tcp_conn->data_rx_hash.tfm);
2183                 }
2184                 tcp_conn->sendpage = conn->datadgst_en ?
2185                         sock_no_sendpage : tcp_conn->sock->ops->sendpage;
2186                 break;
2187         case ISCSI_PARAM_MAX_R2T:
2188                 sscanf(buf, "%d", &value);
2189                 if (session->max_r2t == roundup_pow_of_two(value))
2190                         break;
2191                 iscsi_r2tpool_free(session);
2192                 iscsi_set_param(cls_conn, param, buf, buflen);
2193                 if (session->max_r2t & (session->max_r2t - 1))
2194                         session->max_r2t = roundup_pow_of_two(session->max_r2t);
2195                 if (iscsi_r2tpool_alloc(session))
2196                         return -ENOMEM;
2197                 break;
2198         default:
2199                 return iscsi_set_param(cls_conn, param, buf, buflen);
2200         }
2201
2202         return 0;
2203 }
2204
2205 static int
2206 iscsi_tcp_conn_get_param(struct iscsi_cls_conn *cls_conn,
2207                          enum iscsi_param param, char *buf)
2208 {
2209         struct iscsi_conn *conn = cls_conn->dd_data;
2210         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
2211         struct inet_sock *inet;
2212         struct ipv6_pinfo *np;
2213         struct sock *sk;
2214         int len;
2215
2216         switch(param) {
2217         case ISCSI_PARAM_CONN_PORT:
2218                 mutex_lock(&conn->xmitmutex);
2219                 if (!tcp_conn->sock) {
2220                         mutex_unlock(&conn->xmitmutex);
2221                         return -EINVAL;
2222                 }
2223
2224                 inet = inet_sk(tcp_conn->sock->sk);
2225                 len = sprintf(buf, "%hu\n", be16_to_cpu(inet->dport));
2226                 mutex_unlock(&conn->xmitmutex);
2227                 break;
2228         case ISCSI_PARAM_CONN_ADDRESS:
2229                 mutex_lock(&conn->xmitmutex);
2230                 if (!tcp_conn->sock) {
2231                         mutex_unlock(&conn->xmitmutex);
2232                         return -EINVAL;
2233                 }
2234
2235                 sk = tcp_conn->sock->sk;
2236                 if (sk->sk_family == PF_INET) {
2237                         inet = inet_sk(sk);
2238                         len = sprintf(buf, "%u.%u.%u.%u\n",
2239                                       NIPQUAD(inet->daddr));
2240                 } else {
2241                         np = inet6_sk(sk);
2242                         len = sprintf(buf,
2243                                 "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
2244                                 NIP6(np->daddr));
2245                 }
2246                 mutex_unlock(&conn->xmitmutex);
2247                 break;
2248         default:
2249                 return iscsi_conn_get_param(cls_conn, param, buf);
2250         }
2251
2252         return len;
2253 }
2254
2255 static void
2256 iscsi_conn_get_stats(struct iscsi_cls_conn *cls_conn, struct iscsi_stats *stats)
2257 {
2258         struct iscsi_conn *conn = cls_conn->dd_data;
2259         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
2260
2261         stats->txdata_octets = conn->txdata_octets;
2262         stats->rxdata_octets = conn->rxdata_octets;
2263         stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
2264         stats->dataout_pdus = conn->dataout_pdus_cnt;
2265         stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
2266         stats->datain_pdus = conn->datain_pdus_cnt;
2267         stats->r2t_pdus = conn->r2t_pdus_cnt;
2268         stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
2269         stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
2270         stats->custom_length = 3;
2271         strcpy(stats->custom[0].desc, "tx_sendpage_failures");
2272         stats->custom[0].value = tcp_conn->sendpage_failures_cnt;
2273         strcpy(stats->custom[1].desc, "rx_discontiguous_hdr");
2274         stats->custom[1].value = tcp_conn->discontiguous_hdr_cnt;
2275         strcpy(stats->custom[2].desc, "eh_abort_cnt");
2276         stats->custom[2].value = conn->eh_abort_cnt;
2277 }
2278
2279 static struct iscsi_cls_session *
2280 iscsi_tcp_session_create(struct iscsi_transport *iscsit,
2281                          struct scsi_transport_template *scsit,
2282                          uint32_t initial_cmdsn, uint32_t *hostno)
2283 {
2284         struct iscsi_cls_session *cls_session;
2285         struct iscsi_session *session;
2286         uint32_t hn;
2287         int cmd_i;
2288
2289         cls_session = iscsi_session_setup(iscsit, scsit,
2290                                          sizeof(struct iscsi_tcp_cmd_task),
2291                                          sizeof(struct iscsi_tcp_mgmt_task),
2292                                          initial_cmdsn, &hn);
2293         if (!cls_session)
2294                 return NULL;
2295         *hostno = hn;
2296
2297         session = class_to_transport_session(cls_session);
2298         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
2299                 struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
2300                 struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
2301
2302                 ctask->hdr = &tcp_ctask->hdr;
2303         }
2304
2305         for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++) {
2306                 struct iscsi_mgmt_task *mtask = session->mgmt_cmds[cmd_i];
2307                 struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;
2308
2309                 mtask->hdr = &tcp_mtask->hdr;
2310         }
2311
2312         if (iscsi_r2tpool_alloc(class_to_transport_session(cls_session)))
2313                 goto r2tpool_alloc_fail;
2314
2315         return cls_session;
2316
2317 r2tpool_alloc_fail:
2318         iscsi_session_teardown(cls_session);
2319         return NULL;
2320 }
2321
2322 static void iscsi_tcp_session_destroy(struct iscsi_cls_session *cls_session)
2323 {
2324         iscsi_r2tpool_free(class_to_transport_session(cls_session));
2325         iscsi_session_teardown(cls_session);
2326 }
2327
2328 static struct scsi_host_template iscsi_sht = {
2329         .name                   = "iSCSI Initiator over TCP/IP",
2330         .queuecommand           = iscsi_queuecommand,
2331         .change_queue_depth     = iscsi_change_queue_depth,
2332         .can_queue              = ISCSI_XMIT_CMDS_MAX - 1,
2333         .sg_tablesize           = ISCSI_SG_TABLESIZE,
2334         .cmd_per_lun            = ISCSI_DEF_CMD_PER_LUN,
2335         .eh_abort_handler       = iscsi_eh_abort,
2336         .eh_host_reset_handler  = iscsi_eh_host_reset,
2337         .use_clustering         = DISABLE_CLUSTERING,
2338         .proc_name              = "iscsi_tcp",
2339         .this_id                = -1,
2340 };
2341
2342 static struct iscsi_transport iscsi_tcp_transport = {
2343         .owner                  = THIS_MODULE,
2344         .name                   = "tcp",
2345         .caps                   = CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_HDRDGST
2346                                   | CAP_DATADGST,
2347         .param_mask             = ISCSI_MAX_RECV_DLENGTH |
2348                                   ISCSI_MAX_XMIT_DLENGTH |
2349                                   ISCSI_HDRDGST_EN |
2350                                   ISCSI_DATADGST_EN |
2351                                   ISCSI_INITIAL_R2T_EN |
2352                                   ISCSI_MAX_R2T |
2353                                   ISCSI_IMM_DATA_EN |
2354                                   ISCSI_FIRST_BURST |
2355                                   ISCSI_MAX_BURST |
2356                                   ISCSI_PDU_INORDER_EN |
2357                                   ISCSI_DATASEQ_INORDER_EN |
2358                                   ISCSI_ERL |
2359                                   ISCSI_CONN_PORT |
2360                                   ISCSI_CONN_ADDRESS |
2361                                   ISCSI_EXP_STATSN |
2362                                   ISCSI_PERSISTENT_PORT |
2363                                   ISCSI_PERSISTENT_ADDRESS |
2364                                   ISCSI_TARGET_NAME |
2365                                   ISCSI_TPGT,
2366         .host_template          = &iscsi_sht,
2367         .conndata_size          = sizeof(struct iscsi_conn),
2368         .max_conn               = 1,
2369         .max_cmd_len            = ISCSI_TCP_MAX_CMD_LEN,
2370         /* session management */
2371         .create_session         = iscsi_tcp_session_create,
2372         .destroy_session        = iscsi_tcp_session_destroy,
2373         /* connection management */
2374         .create_conn            = iscsi_tcp_conn_create,
2375         .bind_conn              = iscsi_tcp_conn_bind,
2376         .destroy_conn           = iscsi_tcp_conn_destroy,
2377         .set_param              = iscsi_conn_set_param,
2378         .get_conn_param         = iscsi_tcp_conn_get_param,
2379         .get_session_param      = iscsi_session_get_param,
2380         .start_conn             = iscsi_conn_start,
2381         .stop_conn              = iscsi_tcp_conn_stop,
2382         /* IO */
2383         .send_pdu               = iscsi_conn_send_pdu,
2384         .get_stats              = iscsi_conn_get_stats,
2385         .init_cmd_task          = iscsi_tcp_cmd_init,
2386         .init_mgmt_task         = iscsi_tcp_mgmt_init,
2387         .xmit_cmd_task          = iscsi_tcp_ctask_xmit,
2388         .xmit_mgmt_task         = iscsi_tcp_mtask_xmit,
2389         .cleanup_cmd_task       = iscsi_tcp_cleanup_ctask,
2390         /* recovery */
2391         .session_recovery_timedout = iscsi_session_recovery_timedout,
2392 };
2393
2394 static int __init
2395 iscsi_tcp_init(void)
2396 {
2397         if (iscsi_max_lun < 1) {
2398                 printk(KERN_ERR "iscsi_tcp: Invalid max_lun value of %u\n",
2399                        iscsi_max_lun);
2400                 return -EINVAL;
2401         }
2402         iscsi_tcp_transport.max_lun = iscsi_max_lun;
2403
2404         if (!iscsi_register_transport(&iscsi_tcp_transport))
2405                 return -ENODEV;
2406
2407         return 0;
2408 }
2409
2410 static void __exit
2411 iscsi_tcp_exit(void)
2412 {
2413         iscsi_unregister_transport(&iscsi_tcp_transport);
2414 }
2415
2416 module_init(iscsi_tcp_init);
2417 module_exit(iscsi_tcp_exit);