Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux...
[linux-2.6] / 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/types.h>
30 #include <linux/list.h>
31 #include <linux/inet.h>
32 #include <linux/file.h>
33 #include <linux/blkdev.h>
34 #include <linux/crypto.h>
35 #include <linux/delay.h>
36 #include <linux/kfifo.h>
37 #include <linux/scatterlist.h>
38 #include <net/tcp.h>
39 #include <scsi/scsi_cmnd.h>
40 #include <scsi/scsi_device.h>
41 #include <scsi/scsi_host.h>
42 #include <scsi/scsi.h>
43 #include <scsi/scsi_transport_iscsi.h>
44
45 #include "iscsi_tcp.h"
46
47 MODULE_AUTHOR("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         sg_init_one(&ibuf->sg, vbuf, size);
74         ibuf->sent = 0;
75         ibuf->use_sendmsg = 1;
76 }
77
78 static inline void
79 iscsi_buf_init_sg(struct iscsi_buf *ibuf, struct scatterlist *sg)
80 {
81         sg_init_table(&ibuf->sg, 1);
82         sg_set_page(&ibuf->sg, sg_page(sg), sg->length, sg->offset);
83         /*
84          * Fastpath: sg element fits into single page
85          */
86         if (sg->length + sg->offset <= PAGE_SIZE && !PageSlab(sg_page(sg)))
87                 ibuf->use_sendmsg = 0;
88         else
89                 ibuf->use_sendmsg = 1;
90         ibuf->sent = 0;
91 }
92
93 static inline int
94 iscsi_buf_left(struct iscsi_buf *ibuf)
95 {
96         int rc;
97
98         rc = ibuf->sg.length - ibuf->sent;
99         BUG_ON(rc < 0);
100         return rc;
101 }
102
103 static inline void
104 iscsi_hdr_digest(struct iscsi_conn *conn, struct iscsi_buf *buf,
105                  u8* crc)
106 {
107         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
108
109         crypto_hash_digest(&tcp_conn->tx_hash, &buf->sg, buf->sg.length, crc);
110         buf->sg.length += sizeof(u32);
111 }
112
113 static inline int
114 iscsi_hdr_extract(struct iscsi_tcp_conn *tcp_conn)
115 {
116         struct sk_buff *skb = tcp_conn->in.skb;
117
118         tcp_conn->in.zero_copy_hdr = 0;
119
120         if (tcp_conn->in.copy >= tcp_conn->hdr_size &&
121             tcp_conn->in_progress == IN_PROGRESS_WAIT_HEADER) {
122                 /*
123                  * Zero-copy PDU Header: using connection context
124                  * to store header pointer.
125                  */
126                 if (skb_shinfo(skb)->frag_list == NULL &&
127                     !skb_shinfo(skb)->nr_frags) {
128                         tcp_conn->in.hdr = (struct iscsi_hdr *)
129                                 ((char*)skb->data + tcp_conn->in.offset);
130                         tcp_conn->in.zero_copy_hdr = 1;
131                 } else {
132                         /* ignoring return code since we checked
133                          * in.copy before */
134                         skb_copy_bits(skb, tcp_conn->in.offset,
135                                 &tcp_conn->hdr, tcp_conn->hdr_size);
136                         tcp_conn->in.hdr = &tcp_conn->hdr;
137                 }
138                 tcp_conn->in.offset += tcp_conn->hdr_size;
139                 tcp_conn->in.copy -= tcp_conn->hdr_size;
140         } else {
141                 int hdr_remains;
142                 int copylen;
143
144                 /*
145                  * PDU header scattered across SKB's,
146                  * copying it... This'll happen quite rarely.
147                  */
148
149                 if (tcp_conn->in_progress == IN_PROGRESS_WAIT_HEADER)
150                         tcp_conn->in.hdr_offset = 0;
151
152                 hdr_remains = tcp_conn->hdr_size - tcp_conn->in.hdr_offset;
153                 BUG_ON(hdr_remains <= 0);
154
155                 copylen = min(tcp_conn->in.copy, hdr_remains);
156                 skb_copy_bits(skb, tcp_conn->in.offset,
157                         (char*)&tcp_conn->hdr + tcp_conn->in.hdr_offset,
158                         copylen);
159
160                 debug_tcp("PDU gather offset %d bytes %d in.offset %d "
161                        "in.copy %d\n", tcp_conn->in.hdr_offset, copylen,
162                        tcp_conn->in.offset, tcp_conn->in.copy);
163
164                 tcp_conn->in.offset += copylen;
165                 tcp_conn->in.copy -= copylen;
166                 if (copylen < hdr_remains)  {
167                         tcp_conn->in_progress = IN_PROGRESS_HEADER_GATHER;
168                         tcp_conn->in.hdr_offset += copylen;
169                         return -EAGAIN;
170                 }
171                 tcp_conn->in.hdr = &tcp_conn->hdr;
172                 tcp_conn->discontiguous_hdr_cnt++;
173                 tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
174         }
175
176         return 0;
177 }
178
179 /*
180  * must be called with session lock
181  */
182 static void
183 iscsi_tcp_cleanup_ctask(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
184 {
185         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
186         struct iscsi_r2t_info *r2t;
187         struct scsi_cmnd *sc;
188
189         /* flush ctask's r2t queues */
190         while (__kfifo_get(tcp_ctask->r2tqueue, (void*)&r2t, sizeof(void*))) {
191                 __kfifo_put(tcp_ctask->r2tpool.queue, (void*)&r2t,
192                             sizeof(void*));
193                 debug_scsi("iscsi_tcp_cleanup_ctask pending r2t dropped\n");
194         }
195
196         sc = ctask->sc;
197         if (unlikely(!sc))
198                 return;
199
200         tcp_ctask->xmstate = XMSTATE_VALUE_IDLE;
201         tcp_ctask->r2t = NULL;
202 }
203
204 /**
205  * iscsi_data_rsp - SCSI Data-In Response processing
206  * @conn: iscsi connection
207  * @ctask: scsi command task
208  **/
209 static int
210 iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
211 {
212         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
213         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
214         struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
215         struct iscsi_session *session = conn->session;
216         struct scsi_cmnd *sc = ctask->sc;
217         int datasn = be32_to_cpu(rhdr->datasn);
218
219         iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
220         /*
221          * setup Data-In byte counter (gets decremented..)
222          */
223         ctask->data_count = tcp_conn->in.datalen;
224
225         if (tcp_conn->in.datalen == 0)
226                 return 0;
227
228         if (tcp_ctask->exp_datasn != datasn) {
229                 debug_tcp("%s: ctask->exp_datasn(%d) != rhdr->datasn(%d)\n",
230                           __FUNCTION__, tcp_ctask->exp_datasn, datasn);
231                 return ISCSI_ERR_DATASN;
232         }
233
234         tcp_ctask->exp_datasn++;
235
236         tcp_ctask->data_offset = be32_to_cpu(rhdr->offset);
237         if (tcp_ctask->data_offset + tcp_conn->in.datalen > scsi_bufflen(sc)) {
238                 debug_tcp("%s: data_offset(%d) + data_len(%d) > total_length_in(%d)\n",
239                           __FUNCTION__, tcp_ctask->data_offset,
240                           tcp_conn->in.datalen, scsi_bufflen(sc));
241                 return ISCSI_ERR_DATA_OFFSET;
242         }
243
244         if (rhdr->flags & ISCSI_FLAG_DATA_STATUS) {
245                 conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
246                 if (rhdr->flags & ISCSI_FLAG_DATA_UNDERFLOW) {
247                         int res_count = be32_to_cpu(rhdr->residual_count);
248
249                         if (res_count > 0 &&
250                             res_count <= scsi_bufflen(sc)) {
251                                 scsi_set_resid(sc, res_count);
252                                 sc->result = (DID_OK << 16) | rhdr->cmd_status;
253                         } else
254                                 sc->result = (DID_BAD_TARGET << 16) |
255                                         rhdr->cmd_status;
256                 } else if (rhdr->flags & ISCSI_FLAG_DATA_OVERFLOW) {
257                         scsi_set_resid(sc, be32_to_cpu(rhdr->residual_count));
258                         sc->result = (DID_OK << 16) | rhdr->cmd_status;
259                 } else
260                         sc->result = (DID_OK << 16) | rhdr->cmd_status;
261         }
262
263         conn->datain_pdus_cnt++;
264         return 0;
265 }
266
267 /**
268  * iscsi_solicit_data_init - initialize first Data-Out
269  * @conn: iscsi connection
270  * @ctask: scsi command task
271  * @r2t: R2T info
272  *
273  * Notes:
274  *      Initialize first Data-Out within this R2T sequence and finds
275  *      proper data_offset within this SCSI command.
276  *
277  *      This function is called with connection lock taken.
278  **/
279 static void
280 iscsi_solicit_data_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
281                         struct iscsi_r2t_info *r2t)
282 {
283         struct iscsi_data *hdr;
284         struct scsi_cmnd *sc = ctask->sc;
285         int i, sg_count = 0;
286         struct scatterlist *sg;
287
288         hdr = &r2t->dtask.hdr;
289         memset(hdr, 0, sizeof(struct iscsi_data));
290         hdr->ttt = r2t->ttt;
291         hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
292         r2t->solicit_datasn++;
293         hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
294         memcpy(hdr->lun, ctask->hdr->lun, sizeof(hdr->lun));
295         hdr->itt = ctask->hdr->itt;
296         hdr->exp_statsn = r2t->exp_statsn;
297         hdr->offset = cpu_to_be32(r2t->data_offset);
298         if (r2t->data_length > conn->max_xmit_dlength) {
299                 hton24(hdr->dlength, conn->max_xmit_dlength);
300                 r2t->data_count = conn->max_xmit_dlength;
301                 hdr->flags = 0;
302         } else {
303                 hton24(hdr->dlength, r2t->data_length);
304                 r2t->data_count = r2t->data_length;
305                 hdr->flags = ISCSI_FLAG_CMD_FINAL;
306         }
307         conn->dataout_pdus_cnt++;
308
309         r2t->sent = 0;
310
311         iscsi_buf_init_iov(&r2t->headbuf, (char*)hdr,
312                            sizeof(struct iscsi_hdr));
313
314         sg = scsi_sglist(sc);
315         r2t->sg = NULL;
316         for (i = 0; i < scsi_sg_count(sc); i++, sg += 1) {
317                 /* FIXME: prefetch ? */
318                 if (sg_count + sg->length > r2t->data_offset) {
319                         int page_offset;
320
321                         /* sg page found! */
322
323                         /* offset within this page */
324                         page_offset = r2t->data_offset - sg_count;
325
326                         /* fill in this buffer */
327                         iscsi_buf_init_sg(&r2t->sendbuf, sg);
328                         r2t->sendbuf.sg.offset += page_offset;
329                         r2t->sendbuf.sg.length -= page_offset;
330
331                         /* xmit logic will continue with next one */
332                         r2t->sg = sg + 1;
333                         break;
334                 }
335                 sg_count += sg->length;
336         }
337         BUG_ON(r2t->sg == NULL);
338 }
339
340 /**
341  * iscsi_r2t_rsp - iSCSI R2T Response processing
342  * @conn: iscsi connection
343  * @ctask: scsi command task
344  **/
345 static int
346 iscsi_r2t_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
347 {
348         struct iscsi_r2t_info *r2t;
349         struct iscsi_session *session = conn->session;
350         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
351         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
352         struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
353         int r2tsn = be32_to_cpu(rhdr->r2tsn);
354         int rc;
355
356         if (tcp_conn->in.datalen) {
357                 printk(KERN_ERR "iscsi_tcp: invalid R2t with datalen %d\n",
358                        tcp_conn->in.datalen);
359                 return ISCSI_ERR_DATALEN;
360         }
361
362         if (tcp_ctask->exp_datasn != r2tsn){
363                 debug_tcp("%s: ctask->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
364                           __FUNCTION__, tcp_ctask->exp_datasn, r2tsn);
365                 return ISCSI_ERR_R2TSN;
366         }
367
368         /* fill-in new R2T associated with the task */
369         spin_lock(&session->lock);
370         iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
371
372         if (!ctask->sc || ctask->mtask ||
373              session->state != ISCSI_STATE_LOGGED_IN) {
374                 printk(KERN_INFO "iscsi_tcp: dropping R2T itt %d in "
375                        "recovery...\n", ctask->itt);
376                 spin_unlock(&session->lock);
377                 return 0;
378         }
379
380         rc = __kfifo_get(tcp_ctask->r2tpool.queue, (void*)&r2t, sizeof(void*));
381         BUG_ON(!rc);
382
383         r2t->exp_statsn = rhdr->statsn;
384         r2t->data_length = be32_to_cpu(rhdr->data_length);
385         if (r2t->data_length == 0) {
386                 printk(KERN_ERR "iscsi_tcp: invalid R2T with zero data len\n");
387                 spin_unlock(&session->lock);
388                 return ISCSI_ERR_DATALEN;
389         }
390
391         if (r2t->data_length > session->max_burst)
392                 debug_scsi("invalid R2T with data len %u and max burst %u."
393                            "Attempting to execute request.\n",
394                             r2t->data_length, session->max_burst);
395
396         r2t->data_offset = be32_to_cpu(rhdr->data_offset);
397         if (r2t->data_offset + r2t->data_length > scsi_bufflen(ctask->sc)) {
398                 spin_unlock(&session->lock);
399                 printk(KERN_ERR "iscsi_tcp: invalid R2T with data len %u at "
400                        "offset %u and total length %d\n", r2t->data_length,
401                        r2t->data_offset, scsi_bufflen(ctask->sc));
402                 return ISCSI_ERR_DATALEN;
403         }
404
405         r2t->ttt = rhdr->ttt; /* no flip */
406         r2t->solicit_datasn = 0;
407
408         iscsi_solicit_data_init(conn, ctask, r2t);
409
410         tcp_ctask->exp_datasn = r2tsn + 1;
411         __kfifo_put(tcp_ctask->r2tqueue, (void*)&r2t, sizeof(void*));
412         set_bit(XMSTATE_BIT_SOL_HDR_INIT, &tcp_ctask->xmstate);
413         list_move_tail(&ctask->running, &conn->xmitqueue);
414
415         scsi_queue_work(session->host, &conn->xmitwork);
416         conn->r2t_pdus_cnt++;
417         spin_unlock(&session->lock);
418
419         return 0;
420 }
421
422 static int
423 iscsi_tcp_hdr_recv(struct iscsi_conn *conn)
424 {
425         int rc = 0, opcode, ahslen;
426         struct iscsi_hdr *hdr;
427         struct iscsi_session *session = conn->session;
428         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
429         uint32_t cdgst, rdgst = 0, itt;
430
431         hdr = tcp_conn->in.hdr;
432
433         /* verify PDU length */
434         tcp_conn->in.datalen = ntoh24(hdr->dlength);
435         if (tcp_conn->in.datalen > conn->max_recv_dlength) {
436                 printk(KERN_ERR "iscsi_tcp: datalen %d > %d\n",
437                        tcp_conn->in.datalen, conn->max_recv_dlength);
438                 return ISCSI_ERR_DATALEN;
439         }
440         tcp_conn->data_copied = 0;
441
442         /* read AHS */
443         ahslen = hdr->hlength << 2;
444         tcp_conn->in.offset += ahslen;
445         tcp_conn->in.copy -= ahslen;
446         if (tcp_conn->in.copy < 0) {
447                 printk(KERN_ERR "iscsi_tcp: can't handle AHS with length "
448                        "%d bytes\n", ahslen);
449                 return ISCSI_ERR_AHSLEN;
450         }
451
452         /* calculate read padding */
453         tcp_conn->in.padding = tcp_conn->in.datalen & (ISCSI_PAD_LEN-1);
454         if (tcp_conn->in.padding) {
455                 tcp_conn->in.padding = ISCSI_PAD_LEN - tcp_conn->in.padding;
456                 debug_scsi("read padding %d bytes\n", tcp_conn->in.padding);
457         }
458
459         if (conn->hdrdgst_en) {
460                 struct scatterlist sg;
461
462                 sg_init_one(&sg, (u8 *)hdr,
463                             sizeof(struct iscsi_hdr) + ahslen);
464                 crypto_hash_digest(&tcp_conn->rx_hash, &sg, sg.length,
465                                    (u8 *)&cdgst);
466                 rdgst = *(uint32_t*)((char*)hdr + sizeof(struct iscsi_hdr) +
467                                      ahslen);
468                 if (cdgst != rdgst) {
469                         printk(KERN_ERR "iscsi_tcp: hdrdgst error "
470                                "recv 0x%x calc 0x%x\n", rdgst, cdgst);
471                         return ISCSI_ERR_HDR_DGST;
472                 }
473         }
474
475         opcode = hdr->opcode & ISCSI_OPCODE_MASK;
476         /* verify itt (itt encoding: age+cid+itt) */
477         rc = iscsi_verify_itt(conn, hdr, &itt);
478         if (rc == ISCSI_ERR_NO_SCSI_CMD) {
479                 tcp_conn->in.datalen = 0; /* force drop */
480                 return 0;
481         } else if (rc)
482                 return rc;
483
484         debug_tcp("opcode 0x%x offset %d copy %d ahslen %d datalen %d\n",
485                   opcode, tcp_conn->in.offset, tcp_conn->in.copy,
486                   ahslen, tcp_conn->in.datalen);
487
488         switch(opcode) {
489         case ISCSI_OP_SCSI_DATA_IN:
490                 tcp_conn->in.ctask = session->cmds[itt];
491                 rc = iscsi_data_rsp(conn, tcp_conn->in.ctask);
492                 if (rc)
493                         return rc;
494                 /* fall through */
495         case ISCSI_OP_SCSI_CMD_RSP:
496                 tcp_conn->in.ctask = session->cmds[itt];
497                 if (tcp_conn->in.datalen)
498                         goto copy_hdr;
499
500                 spin_lock(&session->lock);
501                 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
502                 spin_unlock(&session->lock);
503                 break;
504         case ISCSI_OP_R2T:
505                 tcp_conn->in.ctask = session->cmds[itt];
506                 if (ahslen)
507                         rc = ISCSI_ERR_AHSLEN;
508                 else if (tcp_conn->in.ctask->sc->sc_data_direction ==
509                                                                 DMA_TO_DEVICE)
510                         rc = iscsi_r2t_rsp(conn, tcp_conn->in.ctask);
511                 else
512                         rc = ISCSI_ERR_PROTO;
513                 break;
514         case ISCSI_OP_LOGIN_RSP:
515         case ISCSI_OP_TEXT_RSP:
516         case ISCSI_OP_REJECT:
517         case ISCSI_OP_ASYNC_EVENT:
518                 /*
519                  * It is possible that we could get a PDU with a buffer larger
520                  * than 8K, but there are no targets that currently do this.
521                  * For now we fail until we find a vendor that needs it
522                  */
523                 if (ISCSI_DEF_MAX_RECV_SEG_LEN <
524                     tcp_conn->in.datalen) {
525                         printk(KERN_ERR "iscsi_tcp: received buffer of len %u "
526                               "but conn buffer is only %u (opcode %0x)\n",
527                               tcp_conn->in.datalen,
528                               ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
529                         rc = ISCSI_ERR_PROTO;
530                         break;
531                 }
532
533                 if (tcp_conn->in.datalen)
534                         goto copy_hdr;
535         /* fall through */
536         case ISCSI_OP_LOGOUT_RSP:
537         case ISCSI_OP_NOOP_IN:
538         case ISCSI_OP_SCSI_TMFUNC_RSP:
539                 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
540                 break;
541         default:
542                 rc = ISCSI_ERR_BAD_OPCODE;
543                 break;
544         }
545
546         return rc;
547
548 copy_hdr:
549         /*
550          * if we did zero copy for the header but we will need multiple
551          * skbs to complete the command then we have to copy the header
552          * for later use
553          */
554         if (tcp_conn->in.zero_copy_hdr && tcp_conn->in.copy <=
555            (tcp_conn->in.datalen + tcp_conn->in.padding +
556             (conn->datadgst_en ? 4 : 0))) {
557                 debug_tcp("Copying header for later use. in.copy %d in.datalen"
558                           " %d\n", tcp_conn->in.copy, tcp_conn->in.datalen);
559                 memcpy(&tcp_conn->hdr, tcp_conn->in.hdr,
560                        sizeof(struct iscsi_hdr));
561                 tcp_conn->in.hdr = &tcp_conn->hdr;
562                 tcp_conn->in.zero_copy_hdr = 0;
563         }
564         return 0;
565 }
566
567 /**
568  * iscsi_ctask_copy - copy skb bits to the destanation cmd task
569  * @conn: iscsi tcp connection
570  * @ctask: scsi command task
571  * @buf: buffer to copy to
572  * @buf_size: size of buffer
573  * @offset: offset within the buffer
574  *
575  * Notes:
576  *      The function calls skb_copy_bits() and updates per-connection and
577  *      per-cmd byte counters.
578  *
579  *      Read counters (in bytes):
580  *
581  *      conn->in.offset         offset within in progress SKB
582  *      conn->in.copy           left to copy from in progress SKB
583  *                              including padding
584  *      conn->in.copied         copied already from in progress SKB
585  *      conn->data_copied       copied already from in progress buffer
586  *      ctask->sent             total bytes sent up to the MidLayer
587  *      ctask->data_count       left to copy from in progress Data-In
588  *      buf_left                left to copy from in progress buffer
589  **/
590 static inline int
591 iscsi_ctask_copy(struct iscsi_tcp_conn *tcp_conn, struct iscsi_cmd_task *ctask,
592                 void *buf, int buf_size, int offset)
593 {
594         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
595         int buf_left = buf_size - (tcp_conn->data_copied + offset);
596         unsigned size = min(tcp_conn->in.copy, buf_left);
597         int rc;
598
599         size = min(size, ctask->data_count);
600
601         debug_tcp("ctask_copy %d bytes at offset %d copied %d\n",
602                size, tcp_conn->in.offset, tcp_conn->in.copied);
603
604         BUG_ON(size <= 0);
605         BUG_ON(tcp_ctask->sent + size > scsi_bufflen(ctask->sc));
606
607         rc = skb_copy_bits(tcp_conn->in.skb, tcp_conn->in.offset,
608                            (char*)buf + (offset + tcp_conn->data_copied), size);
609         /* must fit into skb->len */
610         BUG_ON(rc);
611
612         tcp_conn->in.offset += size;
613         tcp_conn->in.copy -= size;
614         tcp_conn->in.copied += size;
615         tcp_conn->data_copied += size;
616         tcp_ctask->sent += size;
617         ctask->data_count -= size;
618
619         BUG_ON(tcp_conn->in.copy < 0);
620         BUG_ON(ctask->data_count < 0);
621
622         if (buf_size != (tcp_conn->data_copied + offset)) {
623                 if (!ctask->data_count) {
624                         BUG_ON(buf_size - tcp_conn->data_copied < 0);
625                         /* done with this PDU */
626                         return buf_size - tcp_conn->data_copied;
627                 }
628                 return -EAGAIN;
629         }
630
631         /* done with this buffer or with both - PDU and buffer */
632         tcp_conn->data_copied = 0;
633         return 0;
634 }
635
636 /**
637  * iscsi_tcp_copy - copy skb bits to the destanation buffer
638  * @conn: iscsi tcp connection
639  *
640  * Notes:
641  *      The function calls skb_copy_bits() and updates per-connection
642  *      byte counters.
643  **/
644 static inline int
645 iscsi_tcp_copy(struct iscsi_conn *conn, int buf_size)
646 {
647         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
648         int buf_left = buf_size - tcp_conn->data_copied;
649         int size = min(tcp_conn->in.copy, buf_left);
650         int rc;
651
652         debug_tcp("tcp_copy %d bytes at offset %d copied %d\n",
653                size, tcp_conn->in.offset, tcp_conn->data_copied);
654         BUG_ON(size <= 0);
655
656         rc = skb_copy_bits(tcp_conn->in.skb, tcp_conn->in.offset,
657                            (char*)conn->data + tcp_conn->data_copied, size);
658         BUG_ON(rc);
659
660         tcp_conn->in.offset += size;
661         tcp_conn->in.copy -= size;
662         tcp_conn->in.copied += size;
663         tcp_conn->data_copied += size;
664
665         if (buf_size != tcp_conn->data_copied)
666                 return -EAGAIN;
667
668         return 0;
669 }
670
671 static inline void
672 partial_sg_digest_update(struct hash_desc *desc, struct scatterlist *sg,
673                          int offset, int length)
674 {
675         struct scatterlist temp;
676
677         sg_init_table(&temp, 1);
678         sg_set_page(&temp, sg_page(sg), length, offset);
679         crypto_hash_update(desc, &temp, length);
680 }
681
682 static void
683 iscsi_recv_digest_update(struct iscsi_tcp_conn *tcp_conn, char* buf, int len)
684 {
685         struct scatterlist tmp;
686
687         sg_init_one(&tmp, buf, len);
688         crypto_hash_update(&tcp_conn->rx_hash, &tmp, len);
689 }
690
691 static int iscsi_scsi_data_in(struct iscsi_conn *conn)
692 {
693         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
694         struct iscsi_cmd_task *ctask = tcp_conn->in.ctask;
695         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
696         struct scsi_cmnd *sc = ctask->sc;
697         struct scatterlist *sg;
698         int i, offset, rc = 0;
699
700         BUG_ON((void*)ctask != sc->SCp.ptr);
701
702         offset = tcp_ctask->data_offset;
703         sg = scsi_sglist(sc);
704
705         if (tcp_ctask->data_offset)
706                 for (i = 0; i < tcp_ctask->sg_count; i++)
707                         offset -= sg[i].length;
708         /* we've passed through partial sg*/
709         if (offset < 0)
710                 offset = 0;
711
712         for (i = tcp_ctask->sg_count; i < scsi_sg_count(sc); i++) {
713                 char *dest;
714
715                 dest = kmap_atomic(sg_page(&sg[i]), KM_SOFTIRQ0);
716                 rc = iscsi_ctask_copy(tcp_conn, ctask, dest + sg[i].offset,
717                                       sg[i].length, offset);
718                 kunmap_atomic(dest, KM_SOFTIRQ0);
719                 if (rc == -EAGAIN)
720                         /* continue with the next SKB/PDU */
721                         return rc;
722                 if (!rc) {
723                         if (conn->datadgst_en) {
724                                 if (!offset)
725                                         crypto_hash_update(
726                                                         &tcp_conn->rx_hash,
727                                                         &sg[i], sg[i].length);
728                                 else
729                                         partial_sg_digest_update(
730                                                         &tcp_conn->rx_hash,
731                                                         &sg[i],
732                                                         sg[i].offset + offset,
733                                                         sg[i].length - offset);
734                         }
735                         offset = 0;
736                         tcp_ctask->sg_count++;
737                 }
738
739                 if (!ctask->data_count) {
740                         if (rc && conn->datadgst_en)
741                                 /*
742                                  * data-in is complete, but buffer not...
743                                  */
744                                 partial_sg_digest_update(&tcp_conn->rx_hash,
745                                                          &sg[i],
746                                                          sg[i].offset,
747                                                          sg[i].length-rc);
748                         rc = 0;
749                         break;
750                 }
751
752                 if (!tcp_conn->in.copy)
753                         return -EAGAIN;
754         }
755         BUG_ON(ctask->data_count);
756
757         /* check for non-exceptional status */
758         if (tcp_conn->in.hdr->flags & ISCSI_FLAG_DATA_STATUS) {
759                 debug_scsi("done [sc %lx res %d itt 0x%x flags 0x%x]\n",
760                            (long)sc, sc->result, ctask->itt,
761                            tcp_conn->in.hdr->flags);
762                 spin_lock(&conn->session->lock);
763                 __iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
764                 spin_unlock(&conn->session->lock);
765         }
766
767         return rc;
768 }
769
770 static int
771 iscsi_data_recv(struct iscsi_conn *conn)
772 {
773         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
774         int rc = 0, opcode;
775
776         opcode = tcp_conn->in.hdr->opcode & ISCSI_OPCODE_MASK;
777         switch (opcode) {
778         case ISCSI_OP_SCSI_DATA_IN:
779                 rc = iscsi_scsi_data_in(conn);
780                 break;
781         case ISCSI_OP_SCSI_CMD_RSP:
782         case ISCSI_OP_TEXT_RSP:
783         case ISCSI_OP_LOGIN_RSP:
784         case ISCSI_OP_ASYNC_EVENT:
785         case ISCSI_OP_REJECT:
786                 /*
787                  * Collect data segment to the connection's data
788                  * placeholder
789                  */
790                 if (iscsi_tcp_copy(conn, tcp_conn->in.datalen)) {
791                         rc = -EAGAIN;
792                         goto exit;
793                 }
794
795                 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, conn->data,
796                                         tcp_conn->in.datalen);
797                 if (!rc && conn->datadgst_en && opcode != ISCSI_OP_LOGIN_RSP)
798                         iscsi_recv_digest_update(tcp_conn, conn->data,
799                                                 tcp_conn->in.datalen);
800                 break;
801         default:
802                 BUG_ON(1);
803         }
804 exit:
805         return rc;
806 }
807
808 /**
809  * iscsi_tcp_data_recv - TCP receive in sendfile fashion
810  * @rd_desc: read descriptor
811  * @skb: socket buffer
812  * @offset: offset in skb
813  * @len: skb->len - offset
814  **/
815 static int
816 iscsi_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
817                 unsigned int offset, size_t len)
818 {
819         int rc;
820         struct iscsi_conn *conn = rd_desc->arg.data;
821         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
822         int processed;
823         char pad[ISCSI_PAD_LEN];
824         struct scatterlist sg;
825
826         /*
827          * Save current SKB and its offset in the corresponding
828          * connection context.
829          */
830         tcp_conn->in.copy = skb->len - offset;
831         tcp_conn->in.offset = offset;
832         tcp_conn->in.skb = skb;
833         tcp_conn->in.len = tcp_conn->in.copy;
834         BUG_ON(tcp_conn->in.copy <= 0);
835         debug_tcp("in %d bytes\n", tcp_conn->in.copy);
836
837 more:
838         tcp_conn->in.copied = 0;
839         rc = 0;
840
841         if (unlikely(conn->suspend_rx)) {
842                 debug_tcp("conn %d Rx suspended!\n", conn->id);
843                 return 0;
844         }
845
846         if (tcp_conn->in_progress == IN_PROGRESS_WAIT_HEADER ||
847             tcp_conn->in_progress == IN_PROGRESS_HEADER_GATHER) {
848                 rc = iscsi_hdr_extract(tcp_conn);
849                 if (rc) {
850                        if (rc == -EAGAIN)
851                                 goto nomore;
852                        else {
853                                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
854                                 return 0;
855                        }
856                 }
857
858                 /*
859                  * Verify and process incoming PDU header.
860                  */
861                 rc = iscsi_tcp_hdr_recv(conn);
862                 if (!rc && tcp_conn->in.datalen) {
863                         if (conn->datadgst_en)
864                                 crypto_hash_init(&tcp_conn->rx_hash);
865                         tcp_conn->in_progress = IN_PROGRESS_DATA_RECV;
866                 } else if (rc) {
867                         iscsi_conn_failure(conn, rc);
868                         return 0;
869                 }
870         }
871
872         if (tcp_conn->in_progress == IN_PROGRESS_DDIGEST_RECV &&
873             tcp_conn->in.copy) {
874                 uint32_t recv_digest;
875
876                 debug_tcp("extra data_recv offset %d copy %d\n",
877                           tcp_conn->in.offset, tcp_conn->in.copy);
878
879                 if (!tcp_conn->data_copied) {
880                         if (tcp_conn->in.padding) {
881                                 debug_tcp("padding -> %d\n",
882                                           tcp_conn->in.padding);
883                                 memset(pad, 0, tcp_conn->in.padding);
884                                 sg_init_one(&sg, pad, tcp_conn->in.padding);
885                                 crypto_hash_update(&tcp_conn->rx_hash,
886                                                    &sg, sg.length);
887                         }
888                         crypto_hash_final(&tcp_conn->rx_hash,
889                                           (u8 *) &tcp_conn->in.datadgst);
890                         debug_tcp("rx digest 0x%x\n", tcp_conn->in.datadgst);
891                 }
892
893                 rc = iscsi_tcp_copy(conn, sizeof(uint32_t));
894                 if (rc) {
895                         if (rc == -EAGAIN)
896                                 goto again;
897                         iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
898                         return 0;
899                 }
900
901                 memcpy(&recv_digest, conn->data, sizeof(uint32_t));
902                 if (recv_digest != tcp_conn->in.datadgst) {
903                         debug_tcp("iscsi_tcp: data digest error!"
904                                   "0x%x != 0x%x\n", recv_digest,
905                                   tcp_conn->in.datadgst);
906                         iscsi_conn_failure(conn, ISCSI_ERR_DATA_DGST);
907                         return 0;
908                 } else {
909                         debug_tcp("iscsi_tcp: data digest match!"
910                                   "0x%x == 0x%x\n", recv_digest,
911                                   tcp_conn->in.datadgst);
912                         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
913                 }
914         }
915
916         if (tcp_conn->in_progress == IN_PROGRESS_DATA_RECV &&
917             tcp_conn->in.copy) {
918                 debug_tcp("data_recv offset %d copy %d\n",
919                        tcp_conn->in.offset, tcp_conn->in.copy);
920
921                 rc = iscsi_data_recv(conn);
922                 if (rc) {
923                         if (rc == -EAGAIN)
924                                 goto again;
925                         iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
926                         return 0;
927                 }
928
929                 if (tcp_conn->in.padding)
930                         tcp_conn->in_progress = IN_PROGRESS_PAD_RECV;
931                 else if (conn->datadgst_en)
932                         tcp_conn->in_progress = IN_PROGRESS_DDIGEST_RECV;
933                 else
934                         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
935                 tcp_conn->data_copied = 0;
936         }
937
938         if (tcp_conn->in_progress == IN_PROGRESS_PAD_RECV &&
939             tcp_conn->in.copy) {
940                 int copylen = min(tcp_conn->in.padding - tcp_conn->data_copied,
941                                   tcp_conn->in.copy);
942
943                 tcp_conn->in.copy -= copylen;
944                 tcp_conn->in.offset += copylen;
945                 tcp_conn->data_copied += copylen;
946
947                 if (tcp_conn->data_copied != tcp_conn->in.padding)
948                         tcp_conn->in_progress = IN_PROGRESS_PAD_RECV;
949                 else if (conn->datadgst_en)
950                         tcp_conn->in_progress = IN_PROGRESS_DDIGEST_RECV;
951                 else
952                         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
953                 tcp_conn->data_copied = 0;
954         }
955
956         debug_tcp("f, processed %d from out of %d padding %d\n",
957                tcp_conn->in.offset - offset, (int)len, tcp_conn->in.padding);
958         BUG_ON(tcp_conn->in.offset - offset > len);
959
960         if (tcp_conn->in.offset - offset != len) {
961                 debug_tcp("continue to process %d bytes\n",
962                        (int)len - (tcp_conn->in.offset - offset));
963                 goto more;
964         }
965
966 nomore:
967         processed = tcp_conn->in.offset - offset;
968         BUG_ON(processed == 0);
969         return processed;
970
971 again:
972         processed = tcp_conn->in.offset - offset;
973         debug_tcp("c, processed %d from out of %d rd_desc_cnt %d\n",
974                   processed, (int)len, (int)rd_desc->count);
975         BUG_ON(processed == 0);
976         BUG_ON(processed > len);
977
978         conn->rxdata_octets += processed;
979         return processed;
980 }
981
982 static void
983 iscsi_tcp_data_ready(struct sock *sk, int flag)
984 {
985         struct iscsi_conn *conn = sk->sk_user_data;
986         read_descriptor_t rd_desc;
987
988         read_lock(&sk->sk_callback_lock);
989
990         /*
991          * Use rd_desc to pass 'conn' to iscsi_tcp_data_recv.
992          * We set count to 1 because we want the network layer to
993          * hand us all the skbs that are available. iscsi_tcp_data_recv
994          * handled pdus that cross buffers or pdus that still need data.
995          */
996         rd_desc.arg.data = conn;
997         rd_desc.count = 1;
998         tcp_read_sock(sk, &rd_desc, iscsi_tcp_data_recv);
999
1000         read_unlock(&sk->sk_callback_lock);
1001 }
1002
1003 static void
1004 iscsi_tcp_state_change(struct sock *sk)
1005 {
1006         struct iscsi_tcp_conn *tcp_conn;
1007         struct iscsi_conn *conn;
1008         struct iscsi_session *session;
1009         void (*old_state_change)(struct sock *);
1010
1011         read_lock(&sk->sk_callback_lock);
1012
1013         conn = (struct iscsi_conn*)sk->sk_user_data;
1014         session = conn->session;
1015
1016         if ((sk->sk_state == TCP_CLOSE_WAIT ||
1017              sk->sk_state == TCP_CLOSE) &&
1018             !atomic_read(&sk->sk_rmem_alloc)) {
1019                 debug_tcp("iscsi_tcp_state_change: TCP_CLOSE|TCP_CLOSE_WAIT\n");
1020                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
1021         }
1022
1023         tcp_conn = conn->dd_data;
1024         old_state_change = tcp_conn->old_state_change;
1025
1026         read_unlock(&sk->sk_callback_lock);
1027
1028         old_state_change(sk);
1029 }
1030
1031 /**
1032  * iscsi_write_space - Called when more output buffer space is available
1033  * @sk: socket space is available for
1034  **/
1035 static void
1036 iscsi_write_space(struct sock *sk)
1037 {
1038         struct iscsi_conn *conn = (struct iscsi_conn*)sk->sk_user_data;
1039         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1040
1041         tcp_conn->old_write_space(sk);
1042         debug_tcp("iscsi_write_space: cid %d\n", conn->id);
1043         scsi_queue_work(conn->session->host, &conn->xmitwork);
1044 }
1045
1046 static void
1047 iscsi_conn_set_callbacks(struct iscsi_conn *conn)
1048 {
1049         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1050         struct sock *sk = tcp_conn->sock->sk;
1051
1052         /* assign new callbacks */
1053         write_lock_bh(&sk->sk_callback_lock);
1054         sk->sk_user_data = conn;
1055         tcp_conn->old_data_ready = sk->sk_data_ready;
1056         tcp_conn->old_state_change = sk->sk_state_change;
1057         tcp_conn->old_write_space = sk->sk_write_space;
1058         sk->sk_data_ready = iscsi_tcp_data_ready;
1059         sk->sk_state_change = iscsi_tcp_state_change;
1060         sk->sk_write_space = iscsi_write_space;
1061         write_unlock_bh(&sk->sk_callback_lock);
1062 }
1063
1064 static void
1065 iscsi_conn_restore_callbacks(struct iscsi_tcp_conn *tcp_conn)
1066 {
1067         struct sock *sk = tcp_conn->sock->sk;
1068
1069         /* restore socket callbacks, see also: iscsi_conn_set_callbacks() */
1070         write_lock_bh(&sk->sk_callback_lock);
1071         sk->sk_user_data    = NULL;
1072         sk->sk_data_ready   = tcp_conn->old_data_ready;
1073         sk->sk_state_change = tcp_conn->old_state_change;
1074         sk->sk_write_space  = tcp_conn->old_write_space;
1075         sk->sk_no_check  = 0;
1076         write_unlock_bh(&sk->sk_callback_lock);
1077 }
1078
1079 /**
1080  * iscsi_send - generic send routine
1081  * @sk: kernel's socket
1082  * @buf: buffer to write from
1083  * @size: actual size to write
1084  * @flags: socket's flags
1085  */
1086 static inline int
1087 iscsi_send(struct iscsi_conn *conn, struct iscsi_buf *buf, int size, int flags)
1088 {
1089         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1090         struct socket *sk = tcp_conn->sock;
1091         int offset = buf->sg.offset + buf->sent, res;
1092
1093         /*
1094          * if we got use_sg=0 or are sending something we kmallocd
1095          * then we did not have to do kmap (kmap returns page_address)
1096          *
1097          * if we got use_sg > 0, but had to drop down, we do not
1098          * set clustering so this should only happen for that
1099          * slab case.
1100          */
1101         if (buf->use_sendmsg)
1102                 res = sock_no_sendpage(sk, sg_page(&buf->sg), offset, size, flags);
1103         else
1104                 res = tcp_conn->sendpage(sk, sg_page(&buf->sg), offset, size, flags);
1105
1106         if (res >= 0) {
1107                 conn->txdata_octets += res;
1108                 buf->sent += res;
1109                 return res;
1110         }
1111
1112         tcp_conn->sendpage_failures_cnt++;
1113         if (res == -EAGAIN)
1114                 res = -ENOBUFS;
1115         else
1116                 iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
1117         return res;
1118 }
1119
1120 /**
1121  * iscsi_sendhdr - send PDU Header via tcp_sendpage()
1122  * @conn: iscsi connection
1123  * @buf: buffer to write from
1124  * @datalen: lenght of data to be sent after the header
1125  *
1126  * Notes:
1127  *      (Tx, Fast Path)
1128  **/
1129 static inline int
1130 iscsi_sendhdr(struct iscsi_conn *conn, struct iscsi_buf *buf, int datalen)
1131 {
1132         int flags = 0; /* MSG_DONTWAIT; */
1133         int res, size;
1134
1135         size = buf->sg.length - buf->sent;
1136         BUG_ON(buf->sent + size > buf->sg.length);
1137         if (buf->sent + size != buf->sg.length || datalen)
1138                 flags |= MSG_MORE;
1139
1140         res = iscsi_send(conn, buf, size, flags);
1141         debug_tcp("sendhdr %d bytes, sent %d res %d\n", size, buf->sent, res);
1142         if (res >= 0) {
1143                 if (size != res)
1144                         return -EAGAIN;
1145                 return 0;
1146         }
1147
1148         return res;
1149 }
1150
1151 /**
1152  * iscsi_sendpage - send one page of iSCSI Data-Out.
1153  * @conn: iscsi connection
1154  * @buf: buffer to write from
1155  * @count: remaining data
1156  * @sent: number of bytes sent
1157  *
1158  * Notes:
1159  *      (Tx, Fast Path)
1160  **/
1161 static inline int
1162 iscsi_sendpage(struct iscsi_conn *conn, struct iscsi_buf *buf,
1163                int *count, int *sent)
1164 {
1165         int flags = 0; /* MSG_DONTWAIT; */
1166         int res, size;
1167
1168         size = buf->sg.length - buf->sent;
1169         BUG_ON(buf->sent + size > buf->sg.length);
1170         if (size > *count)
1171                 size = *count;
1172         if (buf->sent + size != buf->sg.length || *count != size)
1173                 flags |= MSG_MORE;
1174
1175         res = iscsi_send(conn, buf, size, flags);
1176         debug_tcp("sendpage: %d bytes, sent %d left %d sent %d res %d\n",
1177                   size, buf->sent, *count, *sent, res);
1178         if (res >= 0) {
1179                 *count -= res;
1180                 *sent += res;
1181                 if (size != res)
1182                         return -EAGAIN;
1183                 return 0;
1184         }
1185
1186         return res;
1187 }
1188
1189 static inline void
1190 iscsi_data_digest_init(struct iscsi_tcp_conn *tcp_conn,
1191                       struct iscsi_tcp_cmd_task *tcp_ctask)
1192 {
1193         crypto_hash_init(&tcp_conn->tx_hash);
1194         tcp_ctask->digest_count = 4;
1195 }
1196
1197 /**
1198  * iscsi_solicit_data_cont - initialize next Data-Out
1199  * @conn: iscsi connection
1200  * @ctask: scsi command task
1201  * @r2t: R2T info
1202  * @left: bytes left to transfer
1203  *
1204  * Notes:
1205  *      Initialize next Data-Out within this R2T sequence and continue
1206  *      to process next Scatter-Gather element(if any) of this SCSI command.
1207  *
1208  *      Called under connection lock.
1209  **/
1210 static void
1211 iscsi_solicit_data_cont(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
1212                         struct iscsi_r2t_info *r2t, int left)
1213 {
1214         struct iscsi_data *hdr;
1215         int new_offset;
1216
1217         hdr = &r2t->dtask.hdr;
1218         memset(hdr, 0, sizeof(struct iscsi_data));
1219         hdr->ttt = r2t->ttt;
1220         hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
1221         r2t->solicit_datasn++;
1222         hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
1223         memcpy(hdr->lun, ctask->hdr->lun, sizeof(hdr->lun));
1224         hdr->itt = ctask->hdr->itt;
1225         hdr->exp_statsn = r2t->exp_statsn;
1226         new_offset = r2t->data_offset + r2t->sent;
1227         hdr->offset = cpu_to_be32(new_offset);
1228         if (left > conn->max_xmit_dlength) {
1229                 hton24(hdr->dlength, conn->max_xmit_dlength);
1230                 r2t->data_count = conn->max_xmit_dlength;
1231         } else {
1232                 hton24(hdr->dlength, left);
1233                 r2t->data_count = left;
1234                 hdr->flags = ISCSI_FLAG_CMD_FINAL;
1235         }
1236         conn->dataout_pdus_cnt++;
1237
1238         iscsi_buf_init_iov(&r2t->headbuf, (char*)hdr,
1239                            sizeof(struct iscsi_hdr));
1240
1241         if (iscsi_buf_left(&r2t->sendbuf))
1242                 return;
1243
1244         iscsi_buf_init_sg(&r2t->sendbuf, r2t->sg);
1245         r2t->sg += 1;
1246 }
1247
1248 static void iscsi_set_padding(struct iscsi_tcp_cmd_task *tcp_ctask,
1249                               unsigned long len)
1250 {
1251         tcp_ctask->pad_count = len & (ISCSI_PAD_LEN - 1);
1252         if (!tcp_ctask->pad_count)
1253                 return;
1254
1255         tcp_ctask->pad_count = ISCSI_PAD_LEN - tcp_ctask->pad_count;
1256         debug_scsi("write padding %d bytes\n", tcp_ctask->pad_count);
1257         set_bit(XMSTATE_BIT_W_PAD, &tcp_ctask->xmstate);
1258 }
1259
1260 /**
1261  * iscsi_tcp_cmd_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
1262  * @conn: iscsi connection
1263  * @ctask: scsi command task
1264  * @sc: scsi command
1265  **/
1266 static void
1267 iscsi_tcp_cmd_init(struct iscsi_cmd_task *ctask)
1268 {
1269         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1270
1271         BUG_ON(__kfifo_len(tcp_ctask->r2tqueue));
1272         tcp_ctask->xmstate = 1 << XMSTATE_BIT_CMD_HDR_INIT;
1273 }
1274
1275 /**
1276  * iscsi_tcp_mtask_xmit - xmit management(immediate) task
1277  * @conn: iscsi connection
1278  * @mtask: task management task
1279  *
1280  * Notes:
1281  *      The function can return -EAGAIN in which case caller must
1282  *      call it again later, or recover. '0' return code means successful
1283  *      xmit.
1284  *
1285  *      Management xmit state machine consists of these states:
1286  *              XMSTATE_BIT_IMM_HDR_INIT - calculate digest of PDU Header
1287  *              XMSTATE_BIT_IMM_HDR      - PDU Header xmit in progress
1288  *              XMSTATE_BIT_IMM_DATA     - PDU Data xmit in progress
1289  *              XMSTATE_VALUE_IDLE       - management PDU is done
1290  **/
1291 static int
1292 iscsi_tcp_mtask_xmit(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask)
1293 {
1294         struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;
1295         int rc;
1296
1297         debug_scsi("mtask deq [cid %d state %x itt 0x%x]\n",
1298                 conn->id, tcp_mtask->xmstate, mtask->itt);
1299
1300         if (test_bit(XMSTATE_BIT_IMM_HDR_INIT, &tcp_mtask->xmstate)) {
1301                 iscsi_buf_init_iov(&tcp_mtask->headbuf, (char*)mtask->hdr,
1302                                    sizeof(struct iscsi_hdr));
1303
1304                 if (mtask->data_count) {
1305                         set_bit(XMSTATE_BIT_IMM_DATA, &tcp_mtask->xmstate);
1306                         iscsi_buf_init_iov(&tcp_mtask->sendbuf,
1307                                            (char*)mtask->data,
1308                                            mtask->data_count);
1309                 }
1310
1311                 if (conn->c_stage != ISCSI_CONN_INITIAL_STAGE &&
1312                     conn->stop_stage != STOP_CONN_RECOVER &&
1313                     conn->hdrdgst_en)
1314                         iscsi_hdr_digest(conn, &tcp_mtask->headbuf,
1315                                         (u8*)tcp_mtask->hdrext);
1316
1317                 tcp_mtask->sent = 0;
1318                 clear_bit(XMSTATE_BIT_IMM_HDR_INIT, &tcp_mtask->xmstate);
1319                 set_bit(XMSTATE_BIT_IMM_HDR, &tcp_mtask->xmstate);
1320         }
1321
1322         if (test_bit(XMSTATE_BIT_IMM_HDR, &tcp_mtask->xmstate)) {
1323                 rc = iscsi_sendhdr(conn, &tcp_mtask->headbuf,
1324                                    mtask->data_count);
1325                 if (rc)
1326                         return rc;
1327                 clear_bit(XMSTATE_BIT_IMM_HDR, &tcp_mtask->xmstate);
1328         }
1329
1330         if (test_and_clear_bit(XMSTATE_BIT_IMM_DATA, &tcp_mtask->xmstate)) {
1331                 BUG_ON(!mtask->data_count);
1332                 /* FIXME: implement.
1333                  * Virtual buffer could be spreaded across multiple pages...
1334                  */
1335                 do {
1336                         int rc;
1337
1338                         rc = iscsi_sendpage(conn, &tcp_mtask->sendbuf,
1339                                         &mtask->data_count, &tcp_mtask->sent);
1340                         if (rc) {
1341                                 set_bit(XMSTATE_BIT_IMM_DATA, &tcp_mtask->xmstate);
1342                                 return rc;
1343                         }
1344                 } while (mtask->data_count);
1345         }
1346
1347         BUG_ON(tcp_mtask->xmstate != XMSTATE_VALUE_IDLE);
1348         if (mtask->hdr->itt == RESERVED_ITT) {
1349                 struct iscsi_session *session = conn->session;
1350
1351                 spin_lock_bh(&session->lock);
1352                 list_del(&conn->mtask->running);
1353                 __kfifo_put(session->mgmtpool.queue, (void*)&conn->mtask,
1354                             sizeof(void*));
1355                 spin_unlock_bh(&session->lock);
1356         }
1357         return 0;
1358 }
1359
1360 static int
1361 iscsi_send_cmd_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1362 {
1363         struct scsi_cmnd *sc = ctask->sc;
1364         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1365         int rc = 0;
1366
1367         if (test_bit(XMSTATE_BIT_CMD_HDR_INIT, &tcp_ctask->xmstate)) {
1368                 tcp_ctask->sent = 0;
1369                 tcp_ctask->sg_count = 0;
1370                 tcp_ctask->exp_datasn = 0;
1371
1372                 if (sc->sc_data_direction == DMA_TO_DEVICE) {
1373                         struct scatterlist *sg = scsi_sglist(sc);
1374
1375                         iscsi_buf_init_sg(&tcp_ctask->sendbuf, sg);
1376                         tcp_ctask->sg = sg + 1;
1377                         tcp_ctask->bad_sg = sg + scsi_sg_count(sc);
1378
1379                         debug_scsi("cmd [itt 0x%x total %d imm_data %d "
1380                                    "unsol count %d, unsol offset %d]\n",
1381                                    ctask->itt, scsi_bufflen(sc),
1382                                    ctask->imm_count, ctask->unsol_count,
1383                                    ctask->unsol_offset);
1384                 }
1385
1386                 iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)ctask->hdr,
1387                                   sizeof(struct iscsi_hdr));
1388
1389                 if (conn->hdrdgst_en)
1390                         iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
1391                                          (u8*)tcp_ctask->hdrext);
1392                 clear_bit(XMSTATE_BIT_CMD_HDR_INIT, &tcp_ctask->xmstate);
1393                 set_bit(XMSTATE_BIT_CMD_HDR_XMIT, &tcp_ctask->xmstate);
1394         }
1395
1396         if (test_bit(XMSTATE_BIT_CMD_HDR_XMIT, &tcp_ctask->xmstate)) {
1397                 rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->imm_count);
1398                 if (rc)
1399                         return rc;
1400                 clear_bit(XMSTATE_BIT_CMD_HDR_XMIT, &tcp_ctask->xmstate);
1401
1402                 if (sc->sc_data_direction != DMA_TO_DEVICE)
1403                         return 0;
1404
1405                 if (ctask->imm_count) {
1406                         set_bit(XMSTATE_BIT_IMM_DATA, &tcp_ctask->xmstate);
1407                         iscsi_set_padding(tcp_ctask, ctask->imm_count);
1408
1409                         if (ctask->conn->datadgst_en) {
1410                                 iscsi_data_digest_init(ctask->conn->dd_data,
1411                                                        tcp_ctask);
1412                                 tcp_ctask->immdigest = 0;
1413                         }
1414                 }
1415
1416                 if (ctask->unsol_count) {
1417                         set_bit(XMSTATE_BIT_UNS_HDR, &tcp_ctask->xmstate);
1418                         set_bit(XMSTATE_BIT_UNS_INIT, &tcp_ctask->xmstate);
1419                 }
1420         }
1421         return rc;
1422 }
1423
1424 static int
1425 iscsi_send_padding(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1426 {
1427         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1428         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1429         int sent = 0, rc;
1430
1431         if (test_bit(XMSTATE_BIT_W_PAD, &tcp_ctask->xmstate)) {
1432                 iscsi_buf_init_iov(&tcp_ctask->sendbuf, (char*)&tcp_ctask->pad,
1433                                    tcp_ctask->pad_count);
1434                 if (conn->datadgst_en)
1435                         crypto_hash_update(&tcp_conn->tx_hash,
1436                                            &tcp_ctask->sendbuf.sg,
1437                                            tcp_ctask->sendbuf.sg.length);
1438         } else if (!test_bit(XMSTATE_BIT_W_RESEND_PAD, &tcp_ctask->xmstate))
1439                 return 0;
1440
1441         clear_bit(XMSTATE_BIT_W_PAD, &tcp_ctask->xmstate);
1442         clear_bit(XMSTATE_BIT_W_RESEND_PAD, &tcp_ctask->xmstate);
1443         debug_scsi("sending %d pad bytes for itt 0x%x\n",
1444                    tcp_ctask->pad_count, ctask->itt);
1445         rc = iscsi_sendpage(conn, &tcp_ctask->sendbuf, &tcp_ctask->pad_count,
1446                            &sent);
1447         if (rc) {
1448                 debug_scsi("padding send failed %d\n", rc);
1449                 set_bit(XMSTATE_BIT_W_RESEND_PAD, &tcp_ctask->xmstate);
1450         }
1451         return rc;
1452 }
1453
1454 static int
1455 iscsi_send_digest(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
1456                         struct iscsi_buf *buf, uint32_t *digest)
1457 {
1458         struct iscsi_tcp_cmd_task *tcp_ctask;
1459         struct iscsi_tcp_conn *tcp_conn;
1460         int rc, sent = 0;
1461
1462         if (!conn->datadgst_en)
1463                 return 0;
1464
1465         tcp_ctask = ctask->dd_data;
1466         tcp_conn = conn->dd_data;
1467
1468         if (!test_bit(XMSTATE_BIT_W_RESEND_DATA_DIGEST, &tcp_ctask->xmstate)) {
1469                 crypto_hash_final(&tcp_conn->tx_hash, (u8*)digest);
1470                 iscsi_buf_init_iov(buf, (char*)digest, 4);
1471         }
1472         clear_bit(XMSTATE_BIT_W_RESEND_DATA_DIGEST, &tcp_ctask->xmstate);
1473
1474         rc = iscsi_sendpage(conn, buf, &tcp_ctask->digest_count, &sent);
1475         if (!rc)
1476                 debug_scsi("sent digest 0x%x for itt 0x%x\n", *digest,
1477                           ctask->itt);
1478         else {
1479                 debug_scsi("sending digest 0x%x failed for itt 0x%x!\n",
1480                           *digest, ctask->itt);
1481                 set_bit(XMSTATE_BIT_W_RESEND_DATA_DIGEST, &tcp_ctask->xmstate);
1482         }
1483         return rc;
1484 }
1485
1486 static int
1487 iscsi_send_data(struct iscsi_cmd_task *ctask, struct iscsi_buf *sendbuf,
1488                 struct scatterlist **sg, int *sent, int *count,
1489                 struct iscsi_buf *digestbuf, uint32_t *digest)
1490 {
1491         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1492         struct iscsi_conn *conn = ctask->conn;
1493         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1494         int rc, buf_sent, offset;
1495
1496         while (*count) {
1497                 buf_sent = 0;
1498                 offset = sendbuf->sent;
1499
1500                 rc = iscsi_sendpage(conn, sendbuf, count, &buf_sent);
1501                 *sent = *sent + buf_sent;
1502                 if (buf_sent && conn->datadgst_en)
1503                         partial_sg_digest_update(&tcp_conn->tx_hash,
1504                                 &sendbuf->sg, sendbuf->sg.offset + offset,
1505                                 buf_sent);
1506                 if (!iscsi_buf_left(sendbuf) && *sg != tcp_ctask->bad_sg) {
1507                         iscsi_buf_init_sg(sendbuf, *sg);
1508                         *sg = *sg + 1;
1509                 }
1510
1511                 if (rc)
1512                         return rc;
1513         }
1514
1515         rc = iscsi_send_padding(conn, ctask);
1516         if (rc)
1517                 return rc;
1518
1519         return iscsi_send_digest(conn, ctask, digestbuf, digest);
1520 }
1521
1522 static int
1523 iscsi_send_unsol_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1524 {
1525         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1526         struct iscsi_data_task *dtask;
1527         int rc;
1528
1529         set_bit(XMSTATE_BIT_UNS_DATA, &tcp_ctask->xmstate);
1530         if (test_bit(XMSTATE_BIT_UNS_INIT, &tcp_ctask->xmstate)) {
1531                 dtask = &tcp_ctask->unsol_dtask;
1532
1533                 iscsi_prep_unsolicit_data_pdu(ctask, &dtask->hdr);
1534                 iscsi_buf_init_iov(&tcp_ctask->headbuf, (char*)&dtask->hdr,
1535                                    sizeof(struct iscsi_hdr));
1536                 if (conn->hdrdgst_en)
1537                         iscsi_hdr_digest(conn, &tcp_ctask->headbuf,
1538                                         (u8*)dtask->hdrext);
1539
1540                 clear_bit(XMSTATE_BIT_UNS_INIT, &tcp_ctask->xmstate);
1541                 iscsi_set_padding(tcp_ctask, ctask->data_count);
1542         }
1543
1544         rc = iscsi_sendhdr(conn, &tcp_ctask->headbuf, ctask->data_count);
1545         if (rc) {
1546                 clear_bit(XMSTATE_BIT_UNS_DATA, &tcp_ctask->xmstate);
1547                 set_bit(XMSTATE_BIT_UNS_HDR, &tcp_ctask->xmstate);
1548                 return rc;
1549         }
1550
1551         if (conn->datadgst_en) {
1552                 dtask = &tcp_ctask->unsol_dtask;
1553                 iscsi_data_digest_init(ctask->conn->dd_data, tcp_ctask);
1554                 dtask->digest = 0;
1555         }
1556
1557         debug_scsi("uns dout [itt 0x%x dlen %d sent %d]\n",
1558                    ctask->itt, ctask->unsol_count, tcp_ctask->sent);
1559         return 0;
1560 }
1561
1562 static int
1563 iscsi_send_unsol_pdu(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1564 {
1565         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1566         int rc;
1567
1568         if (test_and_clear_bit(XMSTATE_BIT_UNS_HDR, &tcp_ctask->xmstate)) {
1569                 BUG_ON(!ctask->unsol_count);
1570 send_hdr:
1571                 rc = iscsi_send_unsol_hdr(conn, ctask);
1572                 if (rc)
1573                         return rc;
1574         }
1575
1576         if (test_bit(XMSTATE_BIT_UNS_DATA, &tcp_ctask->xmstate)) {
1577                 struct iscsi_data_task *dtask = &tcp_ctask->unsol_dtask;
1578                 int start = tcp_ctask->sent;
1579
1580                 rc = iscsi_send_data(ctask, &tcp_ctask->sendbuf, &tcp_ctask->sg,
1581                                      &tcp_ctask->sent, &ctask->data_count,
1582                                      &dtask->digestbuf, &dtask->digest);
1583                 ctask->unsol_count -= tcp_ctask->sent - start;
1584                 if (rc)
1585                         return rc;
1586                 clear_bit(XMSTATE_BIT_UNS_DATA, &tcp_ctask->xmstate);
1587                 /*
1588                  * Done with the Data-Out. Next, check if we need
1589                  * to send another unsolicited Data-Out.
1590                  */
1591                 if (ctask->unsol_count) {
1592                         debug_scsi("sending more uns\n");
1593                         set_bit(XMSTATE_BIT_UNS_INIT, &tcp_ctask->xmstate);
1594                         goto send_hdr;
1595                 }
1596         }
1597         return 0;
1598 }
1599
1600 static int iscsi_send_sol_pdu(struct iscsi_conn *conn,
1601                               struct iscsi_cmd_task *ctask)
1602 {
1603         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1604         struct iscsi_session *session = conn->session;
1605         struct iscsi_r2t_info *r2t;
1606         struct iscsi_data_task *dtask;
1607         int left, rc;
1608
1609         if (test_bit(XMSTATE_BIT_SOL_HDR_INIT, &tcp_ctask->xmstate)) {
1610                 if (!tcp_ctask->r2t) {
1611                         spin_lock_bh(&session->lock);
1612                         __kfifo_get(tcp_ctask->r2tqueue, (void*)&tcp_ctask->r2t,
1613                                     sizeof(void*));
1614                         spin_unlock_bh(&session->lock);
1615                 }
1616 send_hdr:
1617                 r2t = tcp_ctask->r2t;
1618                 dtask = &r2t->dtask;
1619
1620                 if (conn->hdrdgst_en)
1621                         iscsi_hdr_digest(conn, &r2t->headbuf,
1622                                         (u8*)dtask->hdrext);
1623                 clear_bit(XMSTATE_BIT_SOL_HDR_INIT, &tcp_ctask->xmstate);
1624                 set_bit(XMSTATE_BIT_SOL_HDR, &tcp_ctask->xmstate);
1625         }
1626
1627         if (test_bit(XMSTATE_BIT_SOL_HDR, &tcp_ctask->xmstate)) {
1628                 r2t = tcp_ctask->r2t;
1629                 dtask = &r2t->dtask;
1630
1631                 rc = iscsi_sendhdr(conn, &r2t->headbuf, r2t->data_count);
1632                 if (rc)
1633                         return rc;
1634                 clear_bit(XMSTATE_BIT_SOL_HDR, &tcp_ctask->xmstate);
1635                 set_bit(XMSTATE_BIT_SOL_DATA, &tcp_ctask->xmstate);
1636
1637                 if (conn->datadgst_en) {
1638                         iscsi_data_digest_init(conn->dd_data, tcp_ctask);
1639                         dtask->digest = 0;
1640                 }
1641
1642                 iscsi_set_padding(tcp_ctask, r2t->data_count);
1643                 debug_scsi("sol dout [dsn %d itt 0x%x dlen %d sent %d]\n",
1644                         r2t->solicit_datasn - 1, ctask->itt, r2t->data_count,
1645                         r2t->sent);
1646         }
1647
1648         if (test_bit(XMSTATE_BIT_SOL_DATA, &tcp_ctask->xmstate)) {
1649                 r2t = tcp_ctask->r2t;
1650                 dtask = &r2t->dtask;
1651
1652                 rc = iscsi_send_data(ctask, &r2t->sendbuf, &r2t->sg,
1653                                      &r2t->sent, &r2t->data_count,
1654                                      &dtask->digestbuf, &dtask->digest);
1655                 if (rc)
1656                         return rc;
1657                 clear_bit(XMSTATE_BIT_SOL_DATA, &tcp_ctask->xmstate);
1658
1659                 /*
1660                  * Done with this Data-Out. Next, check if we have
1661                  * to send another Data-Out for this R2T.
1662                  */
1663                 BUG_ON(r2t->data_length - r2t->sent < 0);
1664                 left = r2t->data_length - r2t->sent;
1665                 if (left) {
1666                         iscsi_solicit_data_cont(conn, ctask, r2t, left);
1667                         goto send_hdr;
1668                 }
1669
1670                 /*
1671                  * Done with this R2T. Check if there are more
1672                  * outstanding R2Ts ready to be processed.
1673                  */
1674                 spin_lock_bh(&session->lock);
1675                 tcp_ctask->r2t = NULL;
1676                 __kfifo_put(tcp_ctask->r2tpool.queue, (void*)&r2t,
1677                             sizeof(void*));
1678                 if (__kfifo_get(tcp_ctask->r2tqueue, (void*)&r2t,
1679                                 sizeof(void*))) {
1680                         tcp_ctask->r2t = r2t;
1681                         spin_unlock_bh(&session->lock);
1682                         goto send_hdr;
1683                 }
1684                 spin_unlock_bh(&session->lock);
1685         }
1686         return 0;
1687 }
1688
1689 /**
1690  * iscsi_tcp_ctask_xmit - xmit normal PDU task
1691  * @conn: iscsi connection
1692  * @ctask: iscsi command task
1693  *
1694  * Notes:
1695  *      The function can return -EAGAIN in which case caller must
1696  *      call it again later, or recover. '0' return code means successful
1697  *      xmit.
1698  *      The function is devided to logical helpers (above) for the different
1699  *      xmit stages.
1700  *
1701  *iscsi_send_cmd_hdr()
1702  *      XMSTATE_BIT_CMD_HDR_INIT - prepare Header and Data buffers Calculate
1703  *                                 Header Digest
1704  *      XMSTATE_BIT_CMD_HDR_XMIT - Transmit header in progress
1705  *
1706  *iscsi_send_padding
1707  *      XMSTATE_BIT_W_PAD        - Prepare and send pading
1708  *      XMSTATE_BIT_W_RESEND_PAD - retry send pading
1709  *
1710  *iscsi_send_digest
1711  *      XMSTATE_BIT_W_RESEND_DATA_DIGEST - Finalize and send Data Digest
1712  *      XMSTATE_BIT_W_RESEND_DATA_DIGEST - retry sending digest
1713  *
1714  *iscsi_send_unsol_hdr
1715  *      XMSTATE_BIT_UNS_INIT     - prepare un-solicit data header and digest
1716  *      XMSTATE_BIT_UNS_HDR      - send un-solicit header
1717  *
1718  *iscsi_send_unsol_pdu
1719  *      XMSTATE_BIT_UNS_DATA     - send un-solicit data in progress
1720  *
1721  *iscsi_send_sol_pdu
1722  *      XMSTATE_BIT_SOL_HDR_INIT - solicit data header and digest initialize
1723  *      XMSTATE_BIT_SOL_HDR      - send solicit header
1724  *      XMSTATE_BIT_SOL_DATA     - send solicit data
1725  *
1726  *iscsi_tcp_ctask_xmit
1727  *      XMSTATE_BIT_IMM_DATA     - xmit managment data (??)
1728  **/
1729 static int
1730 iscsi_tcp_ctask_xmit(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
1731 {
1732         struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1733         int rc = 0;
1734
1735         debug_scsi("ctask deq [cid %d xmstate %x itt 0x%x]\n",
1736                 conn->id, tcp_ctask->xmstate, ctask->itt);
1737
1738         rc = iscsi_send_cmd_hdr(conn, ctask);
1739         if (rc)
1740                 return rc;
1741         if (ctask->sc->sc_data_direction != DMA_TO_DEVICE)
1742                 return 0;
1743
1744         if (test_bit(XMSTATE_BIT_IMM_DATA, &tcp_ctask->xmstate)) {
1745                 rc = iscsi_send_data(ctask, &tcp_ctask->sendbuf, &tcp_ctask->sg,
1746                                      &tcp_ctask->sent, &ctask->imm_count,
1747                                      &tcp_ctask->immbuf, &tcp_ctask->immdigest);
1748                 if (rc)
1749                         return rc;
1750                 clear_bit(XMSTATE_BIT_IMM_DATA, &tcp_ctask->xmstate);
1751         }
1752
1753         rc = iscsi_send_unsol_pdu(conn, ctask);
1754         if (rc)
1755                 return rc;
1756
1757         rc = iscsi_send_sol_pdu(conn, ctask);
1758         if (rc)
1759                 return rc;
1760
1761         return rc;
1762 }
1763
1764 static struct iscsi_cls_conn *
1765 iscsi_tcp_conn_create(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
1766 {
1767         struct iscsi_conn *conn;
1768         struct iscsi_cls_conn *cls_conn;
1769         struct iscsi_tcp_conn *tcp_conn;
1770
1771         cls_conn = iscsi_conn_setup(cls_session, conn_idx);
1772         if (!cls_conn)
1773                 return NULL;
1774         conn = cls_conn->dd_data;
1775         /*
1776          * due to strange issues with iser these are not set
1777          * in iscsi_conn_setup
1778          */
1779         conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1780
1781         tcp_conn = kzalloc(sizeof(*tcp_conn), GFP_KERNEL);
1782         if (!tcp_conn)
1783                 goto tcp_conn_alloc_fail;
1784
1785         conn->dd_data = tcp_conn;
1786         tcp_conn->iscsi_conn = conn;
1787         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
1788         /* initial operational parameters */
1789         tcp_conn->hdr_size = sizeof(struct iscsi_hdr);
1790
1791         tcp_conn->tx_hash.tfm = crypto_alloc_hash("crc32c", 0,
1792                                                   CRYPTO_ALG_ASYNC);
1793         tcp_conn->tx_hash.flags = 0;
1794         if (IS_ERR(tcp_conn->tx_hash.tfm)) {
1795                 printk(KERN_ERR "Could not create connection due to crc32c "
1796                        "loading error %ld. Make sure the crc32c module is "
1797                        "built as a module or into the kernel\n",
1798                         PTR_ERR(tcp_conn->tx_hash.tfm));
1799                 goto free_tcp_conn;
1800         }
1801
1802         tcp_conn->rx_hash.tfm = crypto_alloc_hash("crc32c", 0,
1803                                                   CRYPTO_ALG_ASYNC);
1804         tcp_conn->rx_hash.flags = 0;
1805         if (IS_ERR(tcp_conn->rx_hash.tfm)) {
1806                 printk(KERN_ERR "Could not create connection due to crc32c "
1807                        "loading error %ld. Make sure the crc32c module is "
1808                        "built as a module or into the kernel\n",
1809                         PTR_ERR(tcp_conn->rx_hash.tfm));
1810                 goto free_tx_tfm;
1811         }
1812
1813         return cls_conn;
1814
1815 free_tx_tfm:
1816         crypto_free_hash(tcp_conn->tx_hash.tfm);
1817 free_tcp_conn:
1818         kfree(tcp_conn);
1819 tcp_conn_alloc_fail:
1820         iscsi_conn_teardown(cls_conn);
1821         return NULL;
1822 }
1823
1824 static void
1825 iscsi_tcp_release_conn(struct iscsi_conn *conn)
1826 {
1827         struct iscsi_session *session = conn->session;
1828         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1829         struct socket *sock = tcp_conn->sock;
1830
1831         if (!sock)
1832                 return;
1833
1834         sock_hold(sock->sk);
1835         iscsi_conn_restore_callbacks(tcp_conn);
1836         sock_put(sock->sk);
1837
1838         spin_lock_bh(&session->lock);
1839         tcp_conn->sock = NULL;
1840         conn->recv_lock = NULL;
1841         spin_unlock_bh(&session->lock);
1842         sockfd_put(sock);
1843 }
1844
1845 static void
1846 iscsi_tcp_conn_destroy(struct iscsi_cls_conn *cls_conn)
1847 {
1848         struct iscsi_conn *conn = cls_conn->dd_data;
1849         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1850
1851         iscsi_tcp_release_conn(conn);
1852         iscsi_conn_teardown(cls_conn);
1853
1854         if (tcp_conn->tx_hash.tfm)
1855                 crypto_free_hash(tcp_conn->tx_hash.tfm);
1856         if (tcp_conn->rx_hash.tfm)
1857                 crypto_free_hash(tcp_conn->rx_hash.tfm);
1858
1859         kfree(tcp_conn);
1860 }
1861
1862 static void
1863 iscsi_tcp_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
1864 {
1865         struct iscsi_conn *conn = cls_conn->dd_data;
1866         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1867
1868         iscsi_conn_stop(cls_conn, flag);
1869         iscsi_tcp_release_conn(conn);
1870         tcp_conn->hdr_size = sizeof(struct iscsi_hdr);
1871 }
1872
1873 static int iscsi_tcp_get_addr(struct iscsi_conn *conn, struct socket *sock,
1874                               char *buf, int *port,
1875                               int (*getname)(struct socket *, struct sockaddr *,
1876                                         int *addrlen))
1877 {
1878         struct sockaddr_storage *addr;
1879         struct sockaddr_in6 *sin6;
1880         struct sockaddr_in *sin;
1881         int rc = 0, len;
1882
1883         addr = kmalloc(sizeof(*addr), GFP_KERNEL);
1884         if (!addr)
1885                 return -ENOMEM;
1886
1887         if (getname(sock, (struct sockaddr *) addr, &len)) {
1888                 rc = -ENODEV;
1889                 goto free_addr;
1890         }
1891
1892         switch (addr->ss_family) {
1893         case AF_INET:
1894                 sin = (struct sockaddr_in *)addr;
1895                 spin_lock_bh(&conn->session->lock);
1896                 sprintf(buf, NIPQUAD_FMT, NIPQUAD(sin->sin_addr.s_addr));
1897                 *port = be16_to_cpu(sin->sin_port);
1898                 spin_unlock_bh(&conn->session->lock);
1899                 break;
1900         case AF_INET6:
1901                 sin6 = (struct sockaddr_in6 *)addr;
1902                 spin_lock_bh(&conn->session->lock);
1903                 sprintf(buf, NIP6_FMT, NIP6(sin6->sin6_addr));
1904                 *port = be16_to_cpu(sin6->sin6_port);
1905                 spin_unlock_bh(&conn->session->lock);
1906                 break;
1907         }
1908 free_addr:
1909         kfree(addr);
1910         return rc;
1911 }
1912
1913 static int
1914 iscsi_tcp_conn_bind(struct iscsi_cls_session *cls_session,
1915                     struct iscsi_cls_conn *cls_conn, uint64_t transport_eph,
1916                     int is_leading)
1917 {
1918         struct iscsi_conn *conn = cls_conn->dd_data;
1919         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
1920         struct sock *sk;
1921         struct socket *sock;
1922         int err;
1923
1924         /* lookup for existing socket */
1925         sock = sockfd_lookup((int)transport_eph, &err);
1926         if (!sock) {
1927                 printk(KERN_ERR "iscsi_tcp: sockfd_lookup failed %d\n", err);
1928                 return -EEXIST;
1929         }
1930         /*
1931          * copy these values now because if we drop the session
1932          * userspace may still want to query the values since we will
1933          * be using them for the reconnect
1934          */
1935         err = iscsi_tcp_get_addr(conn, sock, conn->portal_address,
1936                                  &conn->portal_port, kernel_getpeername);
1937         if (err)
1938                 goto free_socket;
1939
1940         err = iscsi_tcp_get_addr(conn, sock, conn->local_address,
1941                                 &conn->local_port, kernel_getsockname);
1942         if (err)
1943                 goto free_socket;
1944
1945         err = iscsi_conn_bind(cls_session, cls_conn, is_leading);
1946         if (err)
1947                 goto free_socket;
1948
1949         /* bind iSCSI connection and socket */
1950         tcp_conn->sock = sock;
1951
1952         /* setup Socket parameters */
1953         sk = sock->sk;
1954         sk->sk_reuse = 1;
1955         sk->sk_sndtimeo = 15 * HZ; /* FIXME: make it configurable */
1956         sk->sk_allocation = GFP_ATOMIC;
1957
1958         /* FIXME: disable Nagle's algorithm */
1959
1960         /*
1961          * Intercept TCP callbacks for sendfile like receive
1962          * processing.
1963          */
1964         conn->recv_lock = &sk->sk_callback_lock;
1965         iscsi_conn_set_callbacks(conn);
1966         tcp_conn->sendpage = tcp_conn->sock->ops->sendpage;
1967         /*
1968          * set receive state machine into initial state
1969          */
1970         tcp_conn->in_progress = IN_PROGRESS_WAIT_HEADER;
1971         return 0;
1972
1973 free_socket:
1974         sockfd_put(sock);
1975         return err;
1976 }
1977
1978 /* called with host lock */
1979 static void
1980 iscsi_tcp_mgmt_init(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask)
1981 {
1982         struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;
1983         tcp_mtask->xmstate = 1 << XMSTATE_BIT_IMM_HDR_INIT;
1984 }
1985
1986 static int
1987 iscsi_r2tpool_alloc(struct iscsi_session *session)
1988 {
1989         int i;
1990         int cmd_i;
1991
1992         /*
1993          * initialize per-task: R2T pool and xmit queue
1994          */
1995         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1996                 struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
1997                 struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
1998
1999                 /*
2000                  * pre-allocated x4 as much r2ts to handle race when
2001                  * target acks DataOut faster than we data_xmit() queues
2002                  * could replenish r2tqueue.
2003                  */
2004
2005                 /* R2T pool */
2006                 if (iscsi_pool_init(&tcp_ctask->r2tpool, session->max_r2t * 4,
2007                                     (void***)&tcp_ctask->r2ts,
2008                                     sizeof(struct iscsi_r2t_info))) {
2009                         goto r2t_alloc_fail;
2010                 }
2011
2012                 /* R2T xmit queue */
2013                 tcp_ctask->r2tqueue = kfifo_alloc(
2014                       session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL);
2015                 if (tcp_ctask->r2tqueue == ERR_PTR(-ENOMEM)) {
2016                         iscsi_pool_free(&tcp_ctask->r2tpool,
2017                                         (void**)tcp_ctask->r2ts);
2018                         goto r2t_alloc_fail;
2019                 }
2020         }
2021
2022         return 0;
2023
2024 r2t_alloc_fail:
2025         for (i = 0; i < cmd_i; i++) {
2026                 struct iscsi_cmd_task *ctask = session->cmds[i];
2027                 struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
2028
2029                 kfifo_free(tcp_ctask->r2tqueue);
2030                 iscsi_pool_free(&tcp_ctask->r2tpool,
2031                                 (void**)tcp_ctask->r2ts);
2032         }
2033         return -ENOMEM;
2034 }
2035
2036 static void
2037 iscsi_r2tpool_free(struct iscsi_session *session)
2038 {
2039         int i;
2040
2041         for (i = 0; i < session->cmds_max; i++) {
2042                 struct iscsi_cmd_task *ctask = session->cmds[i];
2043                 struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
2044
2045                 kfifo_free(tcp_ctask->r2tqueue);
2046                 iscsi_pool_free(&tcp_ctask->r2tpool,
2047                                 (void**)tcp_ctask->r2ts);
2048         }
2049 }
2050
2051 static int
2052 iscsi_conn_set_param(struct iscsi_cls_conn *cls_conn, enum iscsi_param param,
2053                      char *buf, int buflen)
2054 {
2055         struct iscsi_conn *conn = cls_conn->dd_data;
2056         struct iscsi_session *session = conn->session;
2057         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
2058         int value;
2059
2060         switch(param) {
2061         case ISCSI_PARAM_HDRDGST_EN:
2062                 iscsi_set_param(cls_conn, param, buf, buflen);
2063                 tcp_conn->hdr_size = sizeof(struct iscsi_hdr);
2064                 if (conn->hdrdgst_en)
2065                         tcp_conn->hdr_size += sizeof(__u32);
2066                 break;
2067         case ISCSI_PARAM_DATADGST_EN:
2068                 iscsi_set_param(cls_conn, param, buf, buflen);
2069                 tcp_conn->sendpage = conn->datadgst_en ?
2070                         sock_no_sendpage : tcp_conn->sock->ops->sendpage;
2071                 break;
2072         case ISCSI_PARAM_MAX_R2T:
2073                 sscanf(buf, "%d", &value);
2074                 if (session->max_r2t == roundup_pow_of_two(value))
2075                         break;
2076                 iscsi_r2tpool_free(session);
2077                 iscsi_set_param(cls_conn, param, buf, buflen);
2078                 if (session->max_r2t & (session->max_r2t - 1))
2079                         session->max_r2t = roundup_pow_of_two(session->max_r2t);
2080                 if (iscsi_r2tpool_alloc(session))
2081                         return -ENOMEM;
2082                 break;
2083         default:
2084                 return iscsi_set_param(cls_conn, param, buf, buflen);
2085         }
2086
2087         return 0;
2088 }
2089
2090 static int
2091 iscsi_tcp_conn_get_param(struct iscsi_cls_conn *cls_conn,
2092                          enum iscsi_param param, char *buf)
2093 {
2094         struct iscsi_conn *conn = cls_conn->dd_data;
2095         int len;
2096
2097         switch(param) {
2098         case ISCSI_PARAM_CONN_PORT:
2099                 spin_lock_bh(&conn->session->lock);
2100                 len = sprintf(buf, "%hu\n", conn->portal_port);
2101                 spin_unlock_bh(&conn->session->lock);
2102                 break;
2103         case ISCSI_PARAM_CONN_ADDRESS:
2104                 spin_lock_bh(&conn->session->lock);
2105                 len = sprintf(buf, "%s\n", conn->portal_address);
2106                 spin_unlock_bh(&conn->session->lock);
2107                 break;
2108         default:
2109                 return iscsi_conn_get_param(cls_conn, param, buf);
2110         }
2111
2112         return len;
2113 }
2114
2115 static int
2116 iscsi_tcp_host_get_param(struct Scsi_Host *shost, enum iscsi_host_param param,
2117                          char *buf)
2118 {
2119         struct iscsi_session *session = iscsi_hostdata(shost->hostdata);
2120         int len;
2121
2122         switch (param) {
2123         case ISCSI_HOST_PARAM_IPADDRESS:
2124                 spin_lock_bh(&session->lock);
2125                 if (!session->leadconn)
2126                         len = -ENODEV;
2127                 else
2128                         len = sprintf(buf, "%s\n",
2129                                      session->leadconn->local_address);
2130                 spin_unlock_bh(&session->lock);
2131                 break;
2132         default:
2133                 return iscsi_host_get_param(shost, param, buf);
2134         }
2135         return len;
2136 }
2137
2138 static void
2139 iscsi_conn_get_stats(struct iscsi_cls_conn *cls_conn, struct iscsi_stats *stats)
2140 {
2141         struct iscsi_conn *conn = cls_conn->dd_data;
2142         struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
2143
2144         stats->txdata_octets = conn->txdata_octets;
2145         stats->rxdata_octets = conn->rxdata_octets;
2146         stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
2147         stats->dataout_pdus = conn->dataout_pdus_cnt;
2148         stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
2149         stats->datain_pdus = conn->datain_pdus_cnt;
2150         stats->r2t_pdus = conn->r2t_pdus_cnt;
2151         stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
2152         stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
2153         stats->custom_length = 3;
2154         strcpy(stats->custom[0].desc, "tx_sendpage_failures");
2155         stats->custom[0].value = tcp_conn->sendpage_failures_cnt;
2156         strcpy(stats->custom[1].desc, "rx_discontiguous_hdr");
2157         stats->custom[1].value = tcp_conn->discontiguous_hdr_cnt;
2158         strcpy(stats->custom[2].desc, "eh_abort_cnt");
2159         stats->custom[2].value = conn->eh_abort_cnt;
2160 }
2161
2162 static struct iscsi_cls_session *
2163 iscsi_tcp_session_create(struct iscsi_transport *iscsit,
2164                          struct scsi_transport_template *scsit,
2165                          uint16_t cmds_max, uint16_t qdepth,
2166                          uint32_t initial_cmdsn, uint32_t *hostno)
2167 {
2168         struct iscsi_cls_session *cls_session;
2169         struct iscsi_session *session;
2170         uint32_t hn;
2171         int cmd_i;
2172
2173         cls_session = iscsi_session_setup(iscsit, scsit, cmds_max, qdepth,
2174                                          sizeof(struct iscsi_tcp_cmd_task),
2175                                          sizeof(struct iscsi_tcp_mgmt_task),
2176                                          initial_cmdsn, &hn);
2177         if (!cls_session)
2178                 return NULL;
2179         *hostno = hn;
2180
2181         session = class_to_transport_session(cls_session);
2182         for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
2183                 struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
2184                 struct iscsi_tcp_cmd_task *tcp_ctask = ctask->dd_data;
2185
2186                 ctask->hdr = &tcp_ctask->hdr;
2187         }
2188
2189         for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++) {
2190                 struct iscsi_mgmt_task *mtask = session->mgmt_cmds[cmd_i];
2191                 struct iscsi_tcp_mgmt_task *tcp_mtask = mtask->dd_data;
2192
2193                 mtask->hdr = &tcp_mtask->hdr;
2194         }
2195
2196         if (iscsi_r2tpool_alloc(class_to_transport_session(cls_session)))
2197                 goto r2tpool_alloc_fail;
2198
2199         return cls_session;
2200
2201 r2tpool_alloc_fail:
2202         iscsi_session_teardown(cls_session);
2203         return NULL;
2204 }
2205
2206 static void iscsi_tcp_session_destroy(struct iscsi_cls_session *cls_session)
2207 {
2208         iscsi_r2tpool_free(class_to_transport_session(cls_session));
2209         iscsi_session_teardown(cls_session);
2210 }
2211
2212 static int iscsi_tcp_slave_configure(struct scsi_device *sdev)
2213 {
2214         blk_queue_bounce_limit(sdev->request_queue, BLK_BOUNCE_ANY);
2215         blk_queue_dma_alignment(sdev->request_queue, 0);
2216         return 0;
2217 }
2218
2219 static struct scsi_host_template iscsi_sht = {
2220         .module                 = THIS_MODULE,
2221         .name                   = "iSCSI Initiator over TCP/IP",
2222         .queuecommand           = iscsi_queuecommand,
2223         .change_queue_depth     = iscsi_change_queue_depth,
2224         .can_queue              = ISCSI_DEF_XMIT_CMDS_MAX - 1,
2225         .sg_tablesize           = ISCSI_SG_TABLESIZE,
2226         .max_sectors            = 0xFFFF,
2227         .cmd_per_lun            = ISCSI_DEF_CMD_PER_LUN,
2228         .eh_abort_handler       = iscsi_eh_abort,
2229         .eh_host_reset_handler  = iscsi_eh_host_reset,
2230         .use_clustering         = DISABLE_CLUSTERING,
2231         .slave_configure        = iscsi_tcp_slave_configure,
2232         .proc_name              = "iscsi_tcp",
2233         .this_id                = -1,
2234 };
2235
2236 static struct iscsi_transport iscsi_tcp_transport = {
2237         .owner                  = THIS_MODULE,
2238         .name                   = "tcp",
2239         .caps                   = CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_HDRDGST
2240                                   | CAP_DATADGST,
2241         .param_mask             = ISCSI_MAX_RECV_DLENGTH |
2242                                   ISCSI_MAX_XMIT_DLENGTH |
2243                                   ISCSI_HDRDGST_EN |
2244                                   ISCSI_DATADGST_EN |
2245                                   ISCSI_INITIAL_R2T_EN |
2246                                   ISCSI_MAX_R2T |
2247                                   ISCSI_IMM_DATA_EN |
2248                                   ISCSI_FIRST_BURST |
2249                                   ISCSI_MAX_BURST |
2250                                   ISCSI_PDU_INORDER_EN |
2251                                   ISCSI_DATASEQ_INORDER_EN |
2252                                   ISCSI_ERL |
2253                                   ISCSI_CONN_PORT |
2254                                   ISCSI_CONN_ADDRESS |
2255                                   ISCSI_EXP_STATSN |
2256                                   ISCSI_PERSISTENT_PORT |
2257                                   ISCSI_PERSISTENT_ADDRESS |
2258                                   ISCSI_TARGET_NAME | ISCSI_TPGT |
2259                                   ISCSI_USERNAME | ISCSI_PASSWORD |
2260                                   ISCSI_USERNAME_IN | ISCSI_PASSWORD_IN,
2261         .host_param_mask        = ISCSI_HOST_HWADDRESS | ISCSI_HOST_IPADDRESS |
2262                                   ISCSI_HOST_INITIATOR_NAME |
2263                                   ISCSI_HOST_NETDEV_NAME,
2264         .host_template          = &iscsi_sht,
2265         .conndata_size          = sizeof(struct iscsi_conn),
2266         .max_conn               = 1,
2267         .max_cmd_len            = ISCSI_TCP_MAX_CMD_LEN,
2268         /* session management */
2269         .create_session         = iscsi_tcp_session_create,
2270         .destroy_session        = iscsi_tcp_session_destroy,
2271         /* connection management */
2272         .create_conn            = iscsi_tcp_conn_create,
2273         .bind_conn              = iscsi_tcp_conn_bind,
2274         .destroy_conn           = iscsi_tcp_conn_destroy,
2275         .set_param              = iscsi_conn_set_param,
2276         .get_conn_param         = iscsi_tcp_conn_get_param,
2277         .get_session_param      = iscsi_session_get_param,
2278         .start_conn             = iscsi_conn_start,
2279         .stop_conn              = iscsi_tcp_conn_stop,
2280         /* iscsi host params */
2281         .get_host_param         = iscsi_tcp_host_get_param,
2282         .set_host_param         = iscsi_host_set_param,
2283         /* IO */
2284         .send_pdu               = iscsi_conn_send_pdu,
2285         .get_stats              = iscsi_conn_get_stats,
2286         .init_cmd_task          = iscsi_tcp_cmd_init,
2287         .init_mgmt_task         = iscsi_tcp_mgmt_init,
2288         .xmit_cmd_task          = iscsi_tcp_ctask_xmit,
2289         .xmit_mgmt_task         = iscsi_tcp_mtask_xmit,
2290         .cleanup_cmd_task       = iscsi_tcp_cleanup_ctask,
2291         /* recovery */
2292         .session_recovery_timedout = iscsi_session_recovery_timedout,
2293 };
2294
2295 static int __init
2296 iscsi_tcp_init(void)
2297 {
2298         if (iscsi_max_lun < 1) {
2299                 printk(KERN_ERR "iscsi_tcp: Invalid max_lun value of %u\n",
2300                        iscsi_max_lun);
2301                 return -EINVAL;
2302         }
2303         iscsi_tcp_transport.max_lun = iscsi_max_lun;
2304
2305         if (!iscsi_register_transport(&iscsi_tcp_transport))
2306                 return -ENODEV;
2307
2308         return 0;
2309 }
2310
2311 static void __exit
2312 iscsi_tcp_exit(void)
2313 {
2314         iscsi_unregister_transport(&iscsi_tcp_transport);
2315 }
2316
2317 module_init(iscsi_tcp_init);
2318 module_exit(iscsi_tcp_exit);