cifs: turn read_from_socket into a wrapper around a vectorized version
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / scsi / libiscsi_tcp.c
blob09b232fd9a1bb6c59764ac35f64e7838b5469c4c
1 /*
2 * iSCSI over TCP/IP Data-Path lib
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
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.
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.
20 * See the file COPYING included with this distribution for more details.
22 * Credits:
23 * Christoph Hellwig
24 * FUJITA Tomonori
25 * Arne Redlich
26 * Zhenyu Wang
29 #include <linux/types.h>
30 #include <linux/list.h>
31 #include <linux/inet.h>
32 #include <linux/slab.h>
33 #include <linux/file.h>
34 #include <linux/blkdev.h>
35 #include <linux/crypto.h>
36 #include <linux/delay.h>
37 #include <linux/kfifo.h>
38 #include <linux/scatterlist.h>
39 #include <net/tcp.h>
40 #include <scsi/scsi_cmnd.h>
41 #include <scsi/scsi_device.h>
42 #include <scsi/scsi_host.h>
43 #include <scsi/scsi.h>
44 #include <scsi/scsi_transport_iscsi.h>
46 #include "iscsi_tcp.h"
48 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
49 "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
50 "Alex Aizman <itn780@yahoo.com>");
51 MODULE_DESCRIPTION("iSCSI/TCP data-path");
52 MODULE_LICENSE("GPL");
54 static int iscsi_dbg_libtcp;
55 module_param_named(debug_libiscsi_tcp, iscsi_dbg_libtcp, int,
56 S_IRUGO | S_IWUSR);
57 MODULE_PARM_DESC(debug_libiscsi_tcp, "Turn on debugging for libiscsi_tcp "
58 "module. Set to 1 to turn on, and zero to turn off. Default "
59 "is off.");
61 #define ISCSI_DBG_TCP(_conn, dbg_fmt, arg...) \
62 do { \
63 if (iscsi_dbg_libtcp) \
64 iscsi_conn_printk(KERN_INFO, _conn, \
65 "%s " dbg_fmt, \
66 __func__, ##arg); \
67 } while (0);
69 static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
70 struct iscsi_segment *segment);
73 * Scatterlist handling: inside the iscsi_segment, we
74 * remember an index into the scatterlist, and set data/size
75 * to the current scatterlist entry. For highmem pages, we
76 * kmap as needed.
78 * Note that the page is unmapped when we return from
79 * TCP's data_ready handler, so we may end up mapping and
80 * unmapping the same page repeatedly. The whole reason
81 * for this is that we shouldn't keep the page mapped
82 * outside the softirq.
85 /**
86 * iscsi_tcp_segment_init_sg - init indicated scatterlist entry
87 * @segment: the buffer object
88 * @sg: scatterlist
89 * @offset: byte offset into that sg entry
91 * This function sets up the segment so that subsequent
92 * data is copied to the indicated sg entry, at the given
93 * offset.
95 static inline void
96 iscsi_tcp_segment_init_sg(struct iscsi_segment *segment,
97 struct scatterlist *sg, unsigned int offset)
99 segment->sg = sg;
100 segment->sg_offset = offset;
101 segment->size = min(sg->length - offset,
102 segment->total_size - segment->total_copied);
103 segment->data = NULL;
107 * iscsi_tcp_segment_map - map the current S/G page
108 * @segment: iscsi_segment
109 * @recv: 1 if called from recv path
111 * We only need to possibly kmap data if scatter lists are being used,
112 * because the iscsi passthrough and internal IO paths will never use high
113 * mem pages.
115 static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
117 struct scatterlist *sg;
119 if (segment->data != NULL || !segment->sg)
120 return;
122 sg = segment->sg;
123 BUG_ON(segment->sg_mapped);
124 BUG_ON(sg->length == 0);
127 * If the page count is greater than one it is ok to send
128 * to the network layer's zero copy send path. If not we
129 * have to go the slow sendmsg path. We always map for the
130 * recv path.
132 if (page_count(sg_page(sg)) >= 1 && !recv)
133 return;
135 if (recv) {
136 segment->atomic_mapped = true;
137 segment->sg_mapped = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
138 } else {
139 segment->atomic_mapped = false;
140 /* the xmit path can sleep with the page mapped so use kmap */
141 segment->sg_mapped = kmap(sg_page(sg));
144 segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
147 void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
149 if (segment->sg_mapped) {
150 if (segment->atomic_mapped)
151 kunmap_atomic(segment->sg_mapped, KM_SOFTIRQ0);
152 else
153 kunmap(sg_page(segment->sg));
154 segment->sg_mapped = NULL;
155 segment->data = NULL;
158 EXPORT_SYMBOL_GPL(iscsi_tcp_segment_unmap);
161 * Splice the digest buffer into the buffer
163 static inline void
164 iscsi_tcp_segment_splice_digest(struct iscsi_segment *segment, void *digest)
166 segment->data = digest;
167 segment->digest_len = ISCSI_DIGEST_SIZE;
168 segment->total_size += ISCSI_DIGEST_SIZE;
169 segment->size = ISCSI_DIGEST_SIZE;
170 segment->copied = 0;
171 segment->sg = NULL;
172 segment->hash = NULL;
176 * iscsi_tcp_segment_done - check whether the segment is complete
177 * @tcp_conn: iscsi tcp connection
178 * @segment: iscsi segment to check
179 * @recv: set to one of this is called from the recv path
180 * @copied: number of bytes copied
182 * Check if we're done receiving this segment. If the receive
183 * buffer is full but we expect more data, move on to the
184 * next entry in the scatterlist.
186 * If the amount of data we received isn't a multiple of 4,
187 * we will transparently receive the pad bytes, too.
189 * This function must be re-entrant.
191 int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
192 struct iscsi_segment *segment, int recv,
193 unsigned copied)
195 struct scatterlist sg;
196 unsigned int pad;
198 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copied %u %u size %u %s\n",
199 segment->copied, copied, segment->size,
200 recv ? "recv" : "xmit");
201 if (segment->hash && copied) {
203 * If a segment is kmapd we must unmap it before sending
204 * to the crypto layer since that will try to kmap it again.
206 iscsi_tcp_segment_unmap(segment);
208 if (!segment->data) {
209 sg_init_table(&sg, 1);
210 sg_set_page(&sg, sg_page(segment->sg), copied,
211 segment->copied + segment->sg_offset +
212 segment->sg->offset);
213 } else
214 sg_init_one(&sg, segment->data + segment->copied,
215 copied);
216 crypto_hash_update(segment->hash, &sg, copied);
219 segment->copied += copied;
220 if (segment->copied < segment->size) {
221 iscsi_tcp_segment_map(segment, recv);
222 return 0;
225 segment->total_copied += segment->copied;
226 segment->copied = 0;
227 segment->size = 0;
229 /* Unmap the current scatterlist page, if there is one. */
230 iscsi_tcp_segment_unmap(segment);
232 /* Do we have more scatterlist entries? */
233 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "total copied %u total size %u\n",
234 segment->total_copied, segment->total_size);
235 if (segment->total_copied < segment->total_size) {
236 /* Proceed to the next entry in the scatterlist. */
237 iscsi_tcp_segment_init_sg(segment, sg_next(segment->sg),
239 iscsi_tcp_segment_map(segment, recv);
240 BUG_ON(segment->size == 0);
241 return 0;
244 /* Do we need to handle padding? */
245 if (!(tcp_conn->iscsi_conn->session->tt->caps & CAP_PADDING_OFFLOAD)) {
246 pad = iscsi_padding(segment->total_copied);
247 if (pad != 0) {
248 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
249 "consume %d pad bytes\n", pad);
250 segment->total_size += pad;
251 segment->size = pad;
252 segment->data = segment->padbuf;
253 return 0;
258 * Set us up for transferring the data digest. hdr digest
259 * is completely handled in hdr done function.
261 if (segment->hash) {
262 crypto_hash_final(segment->hash, segment->digest);
263 iscsi_tcp_segment_splice_digest(segment,
264 recv ? segment->recv_digest : segment->digest);
265 return 0;
268 return 1;
270 EXPORT_SYMBOL_GPL(iscsi_tcp_segment_done);
273 * iscsi_tcp_segment_recv - copy data to segment
274 * @tcp_conn: the iSCSI TCP connection
275 * @segment: the buffer to copy to
276 * @ptr: data pointer
277 * @len: amount of data available
279 * This function copies up to @len bytes to the
280 * given buffer, and returns the number of bytes
281 * consumed, which can actually be less than @len.
283 * If hash digest is enabled, the function will update the
284 * hash while copying.
285 * Combining these two operations doesn't buy us a lot (yet),
286 * but in the future we could implement combined copy+crc,
287 * just way we do for network layer checksums.
289 static int
290 iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
291 struct iscsi_segment *segment, const void *ptr,
292 unsigned int len)
294 unsigned int copy = 0, copied = 0;
296 while (!iscsi_tcp_segment_done(tcp_conn, segment, 1, copy)) {
297 if (copied == len) {
298 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
299 "copied %d bytes\n", len);
300 break;
303 copy = min(len - copied, segment->size - segment->copied);
304 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
305 memcpy(segment->data + segment->copied, ptr + copied, copy);
306 copied += copy;
308 return copied;
311 inline void
312 iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr, size_t hdrlen,
313 unsigned char digest[ISCSI_DIGEST_SIZE])
315 struct scatterlist sg;
317 sg_init_one(&sg, hdr, hdrlen);
318 crypto_hash_digest(hash, &sg, hdrlen, digest);
320 EXPORT_SYMBOL_GPL(iscsi_tcp_dgst_header);
322 static inline int
323 iscsi_tcp_dgst_verify(struct iscsi_tcp_conn *tcp_conn,
324 struct iscsi_segment *segment)
326 if (!segment->digest_len)
327 return 1;
329 if (memcmp(segment->recv_digest, segment->digest,
330 segment->digest_len)) {
331 ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "digest mismatch\n");
332 return 0;
335 return 1;
339 * Helper function to set up segment buffer
341 static inline void
342 __iscsi_segment_init(struct iscsi_segment *segment, size_t size,
343 iscsi_segment_done_fn_t *done, struct hash_desc *hash)
345 memset(segment, 0, sizeof(*segment));
346 segment->total_size = size;
347 segment->done = done;
349 if (hash) {
350 segment->hash = hash;
351 crypto_hash_init(hash);
355 inline void
356 iscsi_segment_init_linear(struct iscsi_segment *segment, void *data,
357 size_t size, iscsi_segment_done_fn_t *done,
358 struct hash_desc *hash)
360 __iscsi_segment_init(segment, size, done, hash);
361 segment->data = data;
362 segment->size = size;
364 EXPORT_SYMBOL_GPL(iscsi_segment_init_linear);
366 inline int
367 iscsi_segment_seek_sg(struct iscsi_segment *segment,
368 struct scatterlist *sg_list, unsigned int sg_count,
369 unsigned int offset, size_t size,
370 iscsi_segment_done_fn_t *done, struct hash_desc *hash)
372 struct scatterlist *sg;
373 unsigned int i;
375 __iscsi_segment_init(segment, size, done, hash);
376 for_each_sg(sg_list, sg, sg_count, i) {
377 if (offset < sg->length) {
378 iscsi_tcp_segment_init_sg(segment, sg, offset);
379 return 0;
381 offset -= sg->length;
384 return ISCSI_ERR_DATA_OFFSET;
386 EXPORT_SYMBOL_GPL(iscsi_segment_seek_sg);
389 * iscsi_tcp_hdr_recv_prep - prep segment for hdr reception
390 * @tcp_conn: iscsi connection to prep for
392 * This function always passes NULL for the hash argument, because when this
393 * function is called we do not yet know the final size of the header and want
394 * to delay the digest processing until we know that.
396 void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn)
398 ISCSI_DBG_TCP(tcp_conn->iscsi_conn,
399 "(%s)\n", tcp_conn->iscsi_conn->hdrdgst_en ?
400 "digest enabled" : "digest disabled");
401 iscsi_segment_init_linear(&tcp_conn->in.segment,
402 tcp_conn->in.hdr_buf, sizeof(struct iscsi_hdr),
403 iscsi_tcp_hdr_recv_done, NULL);
405 EXPORT_SYMBOL_GPL(iscsi_tcp_hdr_recv_prep);
408 * Handle incoming reply to any other type of command
410 static int
411 iscsi_tcp_data_recv_done(struct iscsi_tcp_conn *tcp_conn,
412 struct iscsi_segment *segment)
414 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
415 int rc = 0;
417 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
418 return ISCSI_ERR_DATA_DGST;
420 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr,
421 conn->data, tcp_conn->in.datalen);
422 if (rc)
423 return rc;
425 iscsi_tcp_hdr_recv_prep(tcp_conn);
426 return 0;
429 static void
430 iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
432 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
433 struct hash_desc *rx_hash = NULL;
435 if (conn->datadgst_en &&
436 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
437 rx_hash = tcp_conn->rx_hash;
439 iscsi_segment_init_linear(&tcp_conn->in.segment,
440 conn->data, tcp_conn->in.datalen,
441 iscsi_tcp_data_recv_done, rx_hash);
445 * iscsi_tcp_cleanup_task - free tcp_task resources
446 * @task: iscsi task
448 * must be called with session lock
450 void iscsi_tcp_cleanup_task(struct iscsi_task *task)
452 struct iscsi_tcp_task *tcp_task = task->dd_data;
453 struct iscsi_r2t_info *r2t;
455 /* nothing to do for mgmt */
456 if (!task->sc)
457 return;
459 /* flush task's r2t queues */
460 while (kfifo_out(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
461 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
462 sizeof(void*));
463 ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
466 r2t = tcp_task->r2t;
467 if (r2t != NULL) {
468 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
469 sizeof(void*));
470 tcp_task->r2t = NULL;
473 EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
476 * iscsi_tcp_data_in - SCSI Data-In Response processing
477 * @conn: iscsi connection
478 * @task: scsi command task
480 static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
482 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
483 struct iscsi_tcp_task *tcp_task = task->dd_data;
484 struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
485 int datasn = be32_to_cpu(rhdr->datasn);
486 unsigned total_in_length = scsi_in(task->sc)->length;
489 * lib iscsi will update this in the completion handling if there
490 * is status.
492 if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
493 iscsi_update_cmdsn(conn->session, (struct iscsi_nopin*)rhdr);
495 if (tcp_conn->in.datalen == 0)
496 return 0;
498 if (tcp_task->exp_datasn != datasn) {
499 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->datasn(%d)"
500 "\n", tcp_task->exp_datasn, datasn);
501 return ISCSI_ERR_DATASN;
504 tcp_task->exp_datasn++;
506 tcp_task->data_offset = be32_to_cpu(rhdr->offset);
507 if (tcp_task->data_offset + tcp_conn->in.datalen > total_in_length) {
508 ISCSI_DBG_TCP(conn, "data_offset(%d) + data_len(%d) > "
509 "total_length_in(%d)\n", tcp_task->data_offset,
510 tcp_conn->in.datalen, total_in_length);
511 return ISCSI_ERR_DATA_OFFSET;
514 conn->datain_pdus_cnt++;
515 return 0;
519 * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing
520 * @conn: iscsi connection
521 * @task: scsi command task
523 static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
525 struct iscsi_session *session = conn->session;
526 struct iscsi_tcp_task *tcp_task = task->dd_data;
527 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
528 struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr;
529 struct iscsi_r2t_info *r2t;
530 int r2tsn = be32_to_cpu(rhdr->r2tsn);
531 int rc;
533 if (tcp_conn->in.datalen) {
534 iscsi_conn_printk(KERN_ERR, conn,
535 "invalid R2t with datalen %d\n",
536 tcp_conn->in.datalen);
537 return ISCSI_ERR_DATALEN;
540 if (tcp_task->exp_datasn != r2tsn){
541 ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n",
542 tcp_task->exp_datasn, r2tsn);
543 return ISCSI_ERR_R2TSN;
546 /* fill-in new R2T associated with the task */
547 iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
549 if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) {
550 iscsi_conn_printk(KERN_INFO, conn,
551 "dropping R2T itt %d in recovery.\n",
552 task->itt);
553 return 0;
556 rc = kfifo_out(&tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*));
557 if (!rc) {
558 iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
559 "Target has sent more R2Ts than it "
560 "negotiated for or driver has has leaked.\n");
561 return ISCSI_ERR_PROTO;
564 r2t->exp_statsn = rhdr->statsn;
565 r2t->data_length = be32_to_cpu(rhdr->data_length);
566 if (r2t->data_length == 0) {
567 iscsi_conn_printk(KERN_ERR, conn,
568 "invalid R2T with zero data len\n");
569 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
570 sizeof(void*));
571 return ISCSI_ERR_DATALEN;
574 if (r2t->data_length > session->max_burst)
575 ISCSI_DBG_TCP(conn, "invalid R2T with data len %u and max "
576 "burst %u. Attempting to execute request.\n",
577 r2t->data_length, session->max_burst);
579 r2t->data_offset = be32_to_cpu(rhdr->data_offset);
580 if (r2t->data_offset + r2t->data_length > scsi_out(task->sc)->length) {
581 iscsi_conn_printk(KERN_ERR, conn,
582 "invalid R2T with data len %u at offset %u "
583 "and total length %d\n", r2t->data_length,
584 r2t->data_offset, scsi_out(task->sc)->length);
585 kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
586 sizeof(void*));
587 return ISCSI_ERR_DATALEN;
590 r2t->ttt = rhdr->ttt; /* no flip */
591 r2t->datasn = 0;
592 r2t->sent = 0;
594 tcp_task->exp_datasn = r2tsn + 1;
595 kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
596 conn->r2t_pdus_cnt++;
598 iscsi_requeue_task(task);
599 return 0;
603 * Handle incoming reply to DataIn command
605 static int
606 iscsi_tcp_process_data_in(struct iscsi_tcp_conn *tcp_conn,
607 struct iscsi_segment *segment)
609 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
610 struct iscsi_hdr *hdr = tcp_conn->in.hdr;
611 int rc;
613 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
614 return ISCSI_ERR_DATA_DGST;
616 /* check for non-exceptional status */
617 if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
618 rc = iscsi_complete_pdu(conn, tcp_conn->in.hdr, NULL, 0);
619 if (rc)
620 return rc;
623 iscsi_tcp_hdr_recv_prep(tcp_conn);
624 return 0;
628 * iscsi_tcp_hdr_dissect - process PDU header
629 * @conn: iSCSI connection
630 * @hdr: PDU header
632 * This function analyzes the header of the PDU received,
633 * and performs several sanity checks. If the PDU is accompanied
634 * by data, the receive buffer is set up to copy the incoming data
635 * to the correct location.
637 static int
638 iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
640 int rc = 0, opcode, ahslen;
641 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
642 struct iscsi_task *task;
644 /* verify PDU length */
645 tcp_conn->in.datalen = ntoh24(hdr->dlength);
646 if (tcp_conn->in.datalen > conn->max_recv_dlength) {
647 iscsi_conn_printk(KERN_ERR, conn,
648 "iscsi_tcp: datalen %d > %d\n",
649 tcp_conn->in.datalen, conn->max_recv_dlength);
650 return ISCSI_ERR_DATALEN;
653 /* Additional header segments. So far, we don't
654 * process additional headers.
656 ahslen = hdr->hlength << 2;
658 opcode = hdr->opcode & ISCSI_OPCODE_MASK;
659 /* verify itt (itt encoding: age+cid+itt) */
660 rc = iscsi_verify_itt(conn, hdr->itt);
661 if (rc)
662 return rc;
664 ISCSI_DBG_TCP(conn, "opcode 0x%x ahslen %d datalen %d\n",
665 opcode, ahslen, tcp_conn->in.datalen);
667 switch(opcode) {
668 case ISCSI_OP_SCSI_DATA_IN:
669 spin_lock(&conn->session->lock);
670 task = iscsi_itt_to_ctask(conn, hdr->itt);
671 if (!task)
672 rc = ISCSI_ERR_BAD_ITT;
673 else
674 rc = iscsi_tcp_data_in(conn, task);
675 if (rc) {
676 spin_unlock(&conn->session->lock);
677 break;
680 if (tcp_conn->in.datalen) {
681 struct iscsi_tcp_task *tcp_task = task->dd_data;
682 struct hash_desc *rx_hash = NULL;
683 struct scsi_data_buffer *sdb = scsi_in(task->sc);
686 * Setup copy of Data-In into the Scsi_Cmnd
687 * Scatterlist case:
688 * We set up the iscsi_segment to point to the next
689 * scatterlist entry to copy to. As we go along,
690 * we move on to the next scatterlist entry and
691 * update the digest per-entry.
693 if (conn->datadgst_en &&
694 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
695 rx_hash = tcp_conn->rx_hash;
697 ISCSI_DBG_TCP(conn, "iscsi_tcp_begin_data_in( "
698 "offset=%d, datalen=%d)\n",
699 tcp_task->data_offset,
700 tcp_conn->in.datalen);
701 task->last_xfer = jiffies;
702 rc = iscsi_segment_seek_sg(&tcp_conn->in.segment,
703 sdb->table.sgl,
704 sdb->table.nents,
705 tcp_task->data_offset,
706 tcp_conn->in.datalen,
707 iscsi_tcp_process_data_in,
708 rx_hash);
709 spin_unlock(&conn->session->lock);
710 return rc;
712 rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
713 spin_unlock(&conn->session->lock);
714 break;
715 case ISCSI_OP_SCSI_CMD_RSP:
716 if (tcp_conn->in.datalen) {
717 iscsi_tcp_data_recv_prep(tcp_conn);
718 return 0;
720 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
721 break;
722 case ISCSI_OP_R2T:
723 spin_lock(&conn->session->lock);
724 task = iscsi_itt_to_ctask(conn, hdr->itt);
725 if (!task)
726 rc = ISCSI_ERR_BAD_ITT;
727 else if (ahslen)
728 rc = ISCSI_ERR_AHSLEN;
729 else if (task->sc->sc_data_direction == DMA_TO_DEVICE) {
730 task->last_xfer = jiffies;
731 rc = iscsi_tcp_r2t_rsp(conn, task);
732 } else
733 rc = ISCSI_ERR_PROTO;
734 spin_unlock(&conn->session->lock);
735 break;
736 case ISCSI_OP_LOGIN_RSP:
737 case ISCSI_OP_TEXT_RSP:
738 case ISCSI_OP_REJECT:
739 case ISCSI_OP_ASYNC_EVENT:
741 * It is possible that we could get a PDU with a buffer larger
742 * than 8K, but there are no targets that currently do this.
743 * For now we fail until we find a vendor that needs it
745 if (ISCSI_DEF_MAX_RECV_SEG_LEN < tcp_conn->in.datalen) {
746 iscsi_conn_printk(KERN_ERR, conn,
747 "iscsi_tcp: received buffer of "
748 "len %u but conn buffer is only %u "
749 "(opcode %0x)\n",
750 tcp_conn->in.datalen,
751 ISCSI_DEF_MAX_RECV_SEG_LEN, opcode);
752 rc = ISCSI_ERR_PROTO;
753 break;
756 /* If there's data coming in with the response,
757 * receive it to the connection's buffer.
759 if (tcp_conn->in.datalen) {
760 iscsi_tcp_data_recv_prep(tcp_conn);
761 return 0;
763 /* fall through */
764 case ISCSI_OP_LOGOUT_RSP:
765 case ISCSI_OP_NOOP_IN:
766 case ISCSI_OP_SCSI_TMFUNC_RSP:
767 rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
768 break;
769 default:
770 rc = ISCSI_ERR_BAD_OPCODE;
771 break;
774 if (rc == 0) {
775 /* Anything that comes with data should have
776 * been handled above. */
777 if (tcp_conn->in.datalen)
778 return ISCSI_ERR_PROTO;
779 iscsi_tcp_hdr_recv_prep(tcp_conn);
782 return rc;
786 * iscsi_tcp_hdr_recv_done - process PDU header
788 * This is the callback invoked when the PDU header has
789 * been received. If the header is followed by additional
790 * header segments, we go back for more data.
792 static int
793 iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
794 struct iscsi_segment *segment)
796 struct iscsi_conn *conn = tcp_conn->iscsi_conn;
797 struct iscsi_hdr *hdr;
799 /* Check if there are additional header segments
800 * *prior* to computing the digest, because we
801 * may need to go back to the caller for more.
803 hdr = (struct iscsi_hdr *) tcp_conn->in.hdr_buf;
804 if (segment->copied == sizeof(struct iscsi_hdr) && hdr->hlength) {
805 /* Bump the header length - the caller will
806 * just loop around and get the AHS for us, and
807 * call again. */
808 unsigned int ahslen = hdr->hlength << 2;
810 /* Make sure we don't overflow */
811 if (sizeof(*hdr) + ahslen > sizeof(tcp_conn->in.hdr_buf))
812 return ISCSI_ERR_AHSLEN;
814 segment->total_size += ahslen;
815 segment->size += ahslen;
816 return 0;
819 /* We're done processing the header. See if we're doing
820 * header digests; if so, set up the recv_digest buffer
821 * and go back for more. */
822 if (conn->hdrdgst_en &&
823 !(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
824 if (segment->digest_len == 0) {
826 * Even if we offload the digest processing we
827 * splice it in so we can increment the skb/segment
828 * counters in preparation for the data segment.
830 iscsi_tcp_segment_splice_digest(segment,
831 segment->recv_digest);
832 return 0;
835 iscsi_tcp_dgst_header(tcp_conn->rx_hash, hdr,
836 segment->total_copied - ISCSI_DIGEST_SIZE,
837 segment->digest);
839 if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
840 return ISCSI_ERR_HDR_DGST;
843 tcp_conn->in.hdr = hdr;
844 return iscsi_tcp_hdr_dissect(conn, hdr);
848 * iscsi_tcp_recv_segment_is_hdr - tests if we are reading in a header
849 * @tcp_conn: iscsi tcp conn
851 * returns non zero if we are currently processing or setup to process
852 * a header.
854 inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
856 return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
858 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_segment_is_hdr);
861 * iscsi_tcp_recv_skb - Process skb
862 * @conn: iscsi connection
863 * @skb: network buffer with header and/or data segment
864 * @offset: offset in skb
865 * @offload: bool indicating if transfer was offloaded
867 * Will return status of transfer in status. And will return
868 * number of bytes copied.
870 int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
871 unsigned int offset, bool offloaded, int *status)
873 struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
874 struct iscsi_segment *segment = &tcp_conn->in.segment;
875 struct skb_seq_state seq;
876 unsigned int consumed = 0;
877 int rc = 0;
879 ISCSI_DBG_TCP(conn, "in %d bytes\n", skb->len - offset);
881 * Update for each skb instead of pdu, because over slow networks a
882 * data_in's data could take a while to read in. We also want to
883 * account for r2ts.
885 conn->last_recv = jiffies;
887 if (unlikely(conn->suspend_rx)) {
888 ISCSI_DBG_TCP(conn, "Rx suspended!\n");
889 *status = ISCSI_TCP_SUSPENDED;
890 return 0;
893 if (offloaded) {
894 segment->total_copied = segment->total_size;
895 goto segment_done;
898 skb_prepare_seq_read(skb, offset, skb->len, &seq);
899 while (1) {
900 unsigned int avail;
901 const u8 *ptr;
903 avail = skb_seq_read(consumed, &ptr, &seq);
904 if (avail == 0) {
905 ISCSI_DBG_TCP(conn, "no more data avail. Consumed %d\n",
906 consumed);
907 *status = ISCSI_TCP_SKB_DONE;
908 skb_abort_seq_read(&seq);
909 goto skb_done;
911 BUG_ON(segment->copied >= segment->size);
913 ISCSI_DBG_TCP(conn, "skb %p ptr=%p avail=%u\n", skb, ptr,
914 avail);
915 rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
916 BUG_ON(rc == 0);
917 consumed += rc;
919 if (segment->total_copied >= segment->total_size) {
920 skb_abort_seq_read(&seq);
921 goto segment_done;
925 segment_done:
926 *status = ISCSI_TCP_SEGMENT_DONE;
927 ISCSI_DBG_TCP(conn, "segment done\n");
928 rc = segment->done(tcp_conn, segment);
929 if (rc != 0) {
930 *status = ISCSI_TCP_CONN_ERR;
931 ISCSI_DBG_TCP(conn, "Error receiving PDU, errno=%d\n", rc);
932 iscsi_conn_failure(conn, rc);
933 return 0;
935 /* The done() functions sets up the next segment. */
937 skb_done:
938 conn->rxdata_octets += consumed;
939 return consumed;
941 EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
944 * iscsi_tcp_task_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
945 * @conn: iscsi connection
946 * @task: scsi command task
947 * @sc: scsi command
949 int iscsi_tcp_task_init(struct iscsi_task *task)
951 struct iscsi_tcp_task *tcp_task = task->dd_data;
952 struct iscsi_conn *conn = task->conn;
953 struct scsi_cmnd *sc = task->sc;
954 int err;
956 if (!sc) {
958 * mgmt tasks do not have a scatterlist since they come
959 * in from the iscsi interface.
961 ISCSI_DBG_TCP(conn, "mtask deq [itt 0x%x]\n", task->itt);
963 return conn->session->tt->init_pdu(task, 0, task->data_count);
966 BUG_ON(kfifo_len(&tcp_task->r2tqueue));
967 tcp_task->exp_datasn = 0;
969 /* Prepare PDU, optionally w/ immediate data */
970 ISCSI_DBG_TCP(conn, "task deq [itt 0x%x imm %d unsol %d]\n",
971 task->itt, task->imm_count, task->unsol_r2t.data_length);
973 err = conn->session->tt->init_pdu(task, 0, task->imm_count);
974 if (err)
975 return err;
976 task->imm_count = 0;
977 return 0;
979 EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
981 static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
983 struct iscsi_session *session = task->conn->session;
984 struct iscsi_tcp_task *tcp_task = task->dd_data;
985 struct iscsi_r2t_info *r2t = NULL;
987 if (iscsi_task_has_unsol_data(task))
988 r2t = &task->unsol_r2t;
989 else {
990 spin_lock_bh(&session->lock);
991 if (tcp_task->r2t) {
992 r2t = tcp_task->r2t;
993 /* Continue with this R2T? */
994 if (r2t->data_length <= r2t->sent) {
995 ISCSI_DBG_TCP(task->conn,
996 " done with r2t %p\n", r2t);
997 kfifo_in(&tcp_task->r2tpool.queue,
998 (void *)&tcp_task->r2t,
999 sizeof(void *));
1000 tcp_task->r2t = r2t = NULL;
1004 if (r2t == NULL) {
1005 if (kfifo_out(&tcp_task->r2tqueue,
1006 (void *)&tcp_task->r2t, sizeof(void *)) !=
1007 sizeof(void *))
1008 r2t = NULL;
1009 else
1010 r2t = tcp_task->r2t;
1012 spin_unlock_bh(&session->lock);
1015 return r2t;
1019 * iscsi_tcp_task_xmit - xmit normal PDU task
1020 * @task: iscsi command task
1022 * We're expected to return 0 when everything was transmitted successfully,
1023 * -EAGAIN if there's still data in the queue, or != 0 for any other kind
1024 * of error.
1026 int iscsi_tcp_task_xmit(struct iscsi_task *task)
1028 struct iscsi_conn *conn = task->conn;
1029 struct iscsi_session *session = conn->session;
1030 struct iscsi_r2t_info *r2t;
1031 int rc = 0;
1033 flush:
1034 /* Flush any pending data first. */
1035 rc = session->tt->xmit_pdu(task);
1036 if (rc < 0)
1037 return rc;
1039 /* mgmt command */
1040 if (!task->sc) {
1041 if (task->hdr->itt == RESERVED_ITT)
1042 iscsi_put_task(task);
1043 return 0;
1046 /* Are we done already? */
1047 if (task->sc->sc_data_direction != DMA_TO_DEVICE)
1048 return 0;
1050 r2t = iscsi_tcp_get_curr_r2t(task);
1051 if (r2t == NULL) {
1052 /* Waiting for more R2Ts to arrive. */
1053 ISCSI_DBG_TCP(conn, "no R2Ts yet\n");
1054 return 0;
1057 rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_DATA_OUT);
1058 if (rc)
1059 return rc;
1060 iscsi_prep_data_out_pdu(task, r2t, (struct iscsi_data *) task->hdr);
1062 ISCSI_DBG_TCP(conn, "sol dout %p [dsn %d itt 0x%x doff %d dlen %d]\n",
1063 r2t, r2t->datasn - 1, task->hdr->itt,
1064 r2t->data_offset + r2t->sent, r2t->data_count);
1066 rc = conn->session->tt->init_pdu(task, r2t->data_offset + r2t->sent,
1067 r2t->data_count);
1068 if (rc) {
1069 iscsi_conn_failure(conn, ISCSI_ERR_XMIT_FAILED);
1070 return rc;
1073 r2t->sent += r2t->data_count;
1074 goto flush;
1076 EXPORT_SYMBOL_GPL(iscsi_tcp_task_xmit);
1078 struct iscsi_cls_conn *
1079 iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
1080 uint32_t conn_idx)
1083 struct iscsi_conn *conn;
1084 struct iscsi_cls_conn *cls_conn;
1085 struct iscsi_tcp_conn *tcp_conn;
1087 cls_conn = iscsi_conn_setup(cls_session,
1088 sizeof(*tcp_conn) + dd_data_size, conn_idx);
1089 if (!cls_conn)
1090 return NULL;
1091 conn = cls_conn->dd_data;
1093 * due to strange issues with iser these are not set
1094 * in iscsi_conn_setup
1096 conn->max_recv_dlength = ISCSI_DEF_MAX_RECV_SEG_LEN;
1098 tcp_conn = conn->dd_data;
1099 tcp_conn->iscsi_conn = conn;
1100 tcp_conn->dd_data = conn->dd_data + sizeof(*tcp_conn);
1101 return cls_conn;
1103 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_setup);
1105 void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn)
1107 iscsi_conn_teardown(cls_conn);
1109 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_teardown);
1111 int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
1113 int i;
1114 int cmd_i;
1117 * initialize per-task: R2T pool and xmit queue
1119 for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
1120 struct iscsi_task *task = session->cmds[cmd_i];
1121 struct iscsi_tcp_task *tcp_task = task->dd_data;
1124 * pre-allocated x2 as much r2ts to handle race when
1125 * target acks DataOut faster than we data_xmit() queues
1126 * could replenish r2tqueue.
1129 /* R2T pool */
1130 if (iscsi_pool_init(&tcp_task->r2tpool,
1131 session->max_r2t * 2, NULL,
1132 sizeof(struct iscsi_r2t_info))) {
1133 goto r2t_alloc_fail;
1136 /* R2T xmit queue */
1137 if (kfifo_alloc(&tcp_task->r2tqueue,
1138 session->max_r2t * 4 * sizeof(void*), GFP_KERNEL)) {
1139 iscsi_pool_free(&tcp_task->r2tpool);
1140 goto r2t_alloc_fail;
1144 return 0;
1146 r2t_alloc_fail:
1147 for (i = 0; i < cmd_i; i++) {
1148 struct iscsi_task *task = session->cmds[i];
1149 struct iscsi_tcp_task *tcp_task = task->dd_data;
1151 kfifo_free(&tcp_task->r2tqueue);
1152 iscsi_pool_free(&tcp_task->r2tpool);
1154 return -ENOMEM;
1156 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_alloc);
1158 void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
1160 int i;
1162 for (i = 0; i < session->cmds_max; i++) {
1163 struct iscsi_task *task = session->cmds[i];
1164 struct iscsi_tcp_task *tcp_task = task->dd_data;
1166 kfifo_free(&tcp_task->r2tqueue);
1167 iscsi_pool_free(&tcp_task->r2tpool);
1170 EXPORT_SYMBOL_GPL(iscsi_tcp_r2tpool_free);
1172 void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
1173 struct iscsi_stats *stats)
1175 struct iscsi_conn *conn = cls_conn->dd_data;
1177 stats->txdata_octets = conn->txdata_octets;
1178 stats->rxdata_octets = conn->rxdata_octets;
1179 stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
1180 stats->dataout_pdus = conn->dataout_pdus_cnt;
1181 stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
1182 stats->datain_pdus = conn->datain_pdus_cnt;
1183 stats->r2t_pdus = conn->r2t_pdus_cnt;
1184 stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
1185 stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
1187 EXPORT_SYMBOL_GPL(iscsi_tcp_conn_get_stats);