xref: /openbmc/linux/drivers/scsi/libiscsi.c (revision baa7eb025ab14f3cba2e35c0a8648f9c9f01d24f)
1 /*
2  * iSCSI lib functions
3  *
4  * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
5  * Copyright (C) 2004 - 2006 Mike Christie
6  * Copyright (C) 2004 - 2005 Dmitry Yusupov
7  * Copyright (C) 2004 - 2005 Alex Aizman
8  * maintained by open-iscsi@googlegroups.com
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23  */
24 #include <linux/types.h>
25 #include <linux/kfifo.h>
26 #include <linux/delay.h>
27 #include <linux/log2.h>
28 #include <linux/slab.h>
29 #include <asm/unaligned.h>
30 #include <net/tcp.h>
31 #include <scsi/scsi_cmnd.h>
32 #include <scsi/scsi_device.h>
33 #include <scsi/scsi_eh.h>
34 #include <scsi/scsi_tcq.h>
35 #include <scsi/scsi_host.h>
36 #include <scsi/scsi.h>
37 #include <scsi/iscsi_proto.h>
38 #include <scsi/scsi_transport.h>
39 #include <scsi/scsi_transport_iscsi.h>
40 #include <scsi/libiscsi.h>
41 
42 static int iscsi_dbg_lib_conn;
43 module_param_named(debug_libiscsi_conn, iscsi_dbg_lib_conn, int,
44 		   S_IRUGO | S_IWUSR);
45 MODULE_PARM_DESC(debug_libiscsi_conn,
46 		 "Turn on debugging for connections in libiscsi module. "
47 		 "Set to 1 to turn on, and zero to turn off. Default is off.");
48 
49 static int iscsi_dbg_lib_session;
50 module_param_named(debug_libiscsi_session, iscsi_dbg_lib_session, int,
51 		   S_IRUGO | S_IWUSR);
52 MODULE_PARM_DESC(debug_libiscsi_session,
53 		 "Turn on debugging for sessions in libiscsi module. "
54 		 "Set to 1 to turn on, and zero to turn off. Default is off.");
55 
56 static int iscsi_dbg_lib_eh;
57 module_param_named(debug_libiscsi_eh, iscsi_dbg_lib_eh, int,
58 		   S_IRUGO | S_IWUSR);
59 MODULE_PARM_DESC(debug_libiscsi_eh,
60 		 "Turn on debugging for error handling in libiscsi module. "
61 		 "Set to 1 to turn on, and zero to turn off. Default is off.");
62 
63 #define ISCSI_DBG_CONN(_conn, dbg_fmt, arg...)			\
64 	do {							\
65 		if (iscsi_dbg_lib_conn)				\
66 			iscsi_conn_printk(KERN_INFO, _conn,	\
67 					     "%s " dbg_fmt,	\
68 					     __func__, ##arg);	\
69 	} while (0);
70 
71 #define ISCSI_DBG_SESSION(_session, dbg_fmt, arg...)			\
72 	do {								\
73 		if (iscsi_dbg_lib_session)				\
74 			iscsi_session_printk(KERN_INFO, _session,	\
75 					     "%s " dbg_fmt,		\
76 					     __func__, ##arg);		\
77 	} while (0);
78 
79 #define ISCSI_DBG_EH(_session, dbg_fmt, arg...)				\
80 	do {								\
81 		if (iscsi_dbg_lib_eh)					\
82 			iscsi_session_printk(KERN_INFO, _session,	\
83 					     "%s " dbg_fmt,		\
84 					     __func__, ##arg);		\
85 	} while (0);
86 
87 /* Serial Number Arithmetic, 32 bits, less than, RFC1982 */
88 #define SNA32_CHECK 2147483648UL
89 
90 static int iscsi_sna_lt(u32 n1, u32 n2)
91 {
92 	return n1 != n2 && ((n1 < n2 && (n2 - n1 < SNA32_CHECK)) ||
93 			    (n1 > n2 && (n2 - n1 < SNA32_CHECK)));
94 }
95 
96 /* Serial Number Arithmetic, 32 bits, less than, RFC1982 */
97 static int iscsi_sna_lte(u32 n1, u32 n2)
98 {
99 	return n1 == n2 || ((n1 < n2 && (n2 - n1 < SNA32_CHECK)) ||
100 			    (n1 > n2 && (n2 - n1 < SNA32_CHECK)));
101 }
102 
103 inline void iscsi_conn_queue_work(struct iscsi_conn *conn)
104 {
105 	struct Scsi_Host *shost = conn->session->host;
106 	struct iscsi_host *ihost = shost_priv(shost);
107 
108 	if (ihost->workq)
109 		queue_work(ihost->workq, &conn->xmitwork);
110 }
111 EXPORT_SYMBOL_GPL(iscsi_conn_queue_work);
112 
113 static void __iscsi_update_cmdsn(struct iscsi_session *session,
114 				 uint32_t exp_cmdsn, uint32_t max_cmdsn)
115 {
116 	/*
117 	 * standard specifies this check for when to update expected and
118 	 * max sequence numbers
119 	 */
120 	if (iscsi_sna_lt(max_cmdsn, exp_cmdsn - 1))
121 		return;
122 
123 	if (exp_cmdsn != session->exp_cmdsn &&
124 	    !iscsi_sna_lt(exp_cmdsn, session->exp_cmdsn))
125 		session->exp_cmdsn = exp_cmdsn;
126 
127 	if (max_cmdsn != session->max_cmdsn &&
128 	    !iscsi_sna_lt(max_cmdsn, session->max_cmdsn)) {
129 		session->max_cmdsn = max_cmdsn;
130 		/*
131 		 * if the window closed with IO queued, then kick the
132 		 * xmit thread
133 		 */
134 		if (!list_empty(&session->leadconn->cmdqueue) ||
135 		    !list_empty(&session->leadconn->mgmtqueue))
136 			iscsi_conn_queue_work(session->leadconn);
137 	}
138 }
139 
140 void iscsi_update_cmdsn(struct iscsi_session *session, struct iscsi_nopin *hdr)
141 {
142 	__iscsi_update_cmdsn(session, be32_to_cpu(hdr->exp_cmdsn),
143 			     be32_to_cpu(hdr->max_cmdsn));
144 }
145 EXPORT_SYMBOL_GPL(iscsi_update_cmdsn);
146 
147 /**
148  * iscsi_prep_data_out_pdu - initialize Data-Out
149  * @task: scsi command task
150  * @r2t: R2T info
151  * @hdr: iscsi data in pdu
152  *
153  * Notes:
154  *	Initialize Data-Out within this R2T sequence and finds
155  *	proper data_offset within this SCSI command.
156  *
157  *	This function is called with connection lock taken.
158  **/
159 void iscsi_prep_data_out_pdu(struct iscsi_task *task, struct iscsi_r2t_info *r2t,
160 			   struct iscsi_data *hdr)
161 {
162 	struct iscsi_conn *conn = task->conn;
163 	unsigned int left = r2t->data_length - r2t->sent;
164 
165 	task->hdr_len = sizeof(struct iscsi_data);
166 
167 	memset(hdr, 0, sizeof(struct iscsi_data));
168 	hdr->ttt = r2t->ttt;
169 	hdr->datasn = cpu_to_be32(r2t->datasn);
170 	r2t->datasn++;
171 	hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
172 	memcpy(hdr->lun, task->lun, sizeof(hdr->lun));
173 	hdr->itt = task->hdr_itt;
174 	hdr->exp_statsn = r2t->exp_statsn;
175 	hdr->offset = cpu_to_be32(r2t->data_offset + r2t->sent);
176 	if (left > conn->max_xmit_dlength) {
177 		hton24(hdr->dlength, conn->max_xmit_dlength);
178 		r2t->data_count = conn->max_xmit_dlength;
179 		hdr->flags = 0;
180 	} else {
181 		hton24(hdr->dlength, left);
182 		r2t->data_count = left;
183 		hdr->flags = ISCSI_FLAG_CMD_FINAL;
184 	}
185 	conn->dataout_pdus_cnt++;
186 }
187 EXPORT_SYMBOL_GPL(iscsi_prep_data_out_pdu);
188 
189 static int iscsi_add_hdr(struct iscsi_task *task, unsigned len)
190 {
191 	unsigned exp_len = task->hdr_len + len;
192 
193 	if (exp_len > task->hdr_max) {
194 		WARN_ON(1);
195 		return -EINVAL;
196 	}
197 
198 	WARN_ON(len & (ISCSI_PAD_LEN - 1)); /* caller must pad the AHS */
199 	task->hdr_len = exp_len;
200 	return 0;
201 }
202 
203 /*
204  * make an extended cdb AHS
205  */
206 static int iscsi_prep_ecdb_ahs(struct iscsi_task *task)
207 {
208 	struct scsi_cmnd *cmd = task->sc;
209 	unsigned rlen, pad_len;
210 	unsigned short ahslength;
211 	struct iscsi_ecdb_ahdr *ecdb_ahdr;
212 	int rc;
213 
214 	ecdb_ahdr = iscsi_next_hdr(task);
215 	rlen = cmd->cmd_len - ISCSI_CDB_SIZE;
216 
217 	BUG_ON(rlen > sizeof(ecdb_ahdr->ecdb));
218 	ahslength = rlen + sizeof(ecdb_ahdr->reserved);
219 
220 	pad_len = iscsi_padding(rlen);
221 
222 	rc = iscsi_add_hdr(task, sizeof(ecdb_ahdr->ahslength) +
223 	                   sizeof(ecdb_ahdr->ahstype) + ahslength + pad_len);
224 	if (rc)
225 		return rc;
226 
227 	if (pad_len)
228 		memset(&ecdb_ahdr->ecdb[rlen], 0, pad_len);
229 
230 	ecdb_ahdr->ahslength = cpu_to_be16(ahslength);
231 	ecdb_ahdr->ahstype = ISCSI_AHSTYPE_CDB;
232 	ecdb_ahdr->reserved = 0;
233 	memcpy(ecdb_ahdr->ecdb, cmd->cmnd + ISCSI_CDB_SIZE, rlen);
234 
235 	ISCSI_DBG_SESSION(task->conn->session,
236 			  "iscsi_prep_ecdb_ahs: varlen_cdb_len %d "
237 		          "rlen %d pad_len %d ahs_length %d iscsi_headers_size "
238 		          "%u\n", cmd->cmd_len, rlen, pad_len, ahslength,
239 		          task->hdr_len);
240 	return 0;
241 }
242 
243 static int iscsi_prep_bidi_ahs(struct iscsi_task *task)
244 {
245 	struct scsi_cmnd *sc = task->sc;
246 	struct iscsi_rlength_ahdr *rlen_ahdr;
247 	int rc;
248 
249 	rlen_ahdr = iscsi_next_hdr(task);
250 	rc = iscsi_add_hdr(task, sizeof(*rlen_ahdr));
251 	if (rc)
252 		return rc;
253 
254 	rlen_ahdr->ahslength =
255 		cpu_to_be16(sizeof(rlen_ahdr->read_length) +
256 						  sizeof(rlen_ahdr->reserved));
257 	rlen_ahdr->ahstype = ISCSI_AHSTYPE_RLENGTH;
258 	rlen_ahdr->reserved = 0;
259 	rlen_ahdr->read_length = cpu_to_be32(scsi_in(sc)->length);
260 
261 	ISCSI_DBG_SESSION(task->conn->session,
262 			  "bidi-in rlen_ahdr->read_length(%d) "
263 		          "rlen_ahdr->ahslength(%d)\n",
264 		          be32_to_cpu(rlen_ahdr->read_length),
265 		          be16_to_cpu(rlen_ahdr->ahslength));
266 	return 0;
267 }
268 
269 /**
270  * iscsi_check_tmf_restrictions - check if a task is affected by TMF
271  * @task: iscsi task
272  * @opcode: opcode to check for
273  *
274  * During TMF a task has to be checked if it's affected.
275  * All unrelated I/O can be passed through, but I/O to the
276  * affected LUN should be restricted.
277  * If 'fast_abort' is set we won't be sending any I/O to the
278  * affected LUN.
279  * Otherwise the target is waiting for all TTTs to be completed,
280  * so we have to send all outstanding Data-Out PDUs to the target.
281  */
282 static int iscsi_check_tmf_restrictions(struct iscsi_task *task, int opcode)
283 {
284 	struct iscsi_conn *conn = task->conn;
285 	struct iscsi_tm *tmf = &conn->tmhdr;
286 	unsigned int hdr_lun;
287 
288 	if (conn->tmf_state == TMF_INITIAL)
289 		return 0;
290 
291 	if ((tmf->opcode & ISCSI_OPCODE_MASK) != ISCSI_OP_SCSI_TMFUNC)
292 		return 0;
293 
294 	switch (ISCSI_TM_FUNC_VALUE(tmf)) {
295 	case ISCSI_TM_FUNC_LOGICAL_UNIT_RESET:
296 		/*
297 		 * Allow PDUs for unrelated LUNs
298 		 */
299 		hdr_lun = scsilun_to_int((struct scsi_lun *)tmf->lun);
300 		if (hdr_lun != task->sc->device->lun)
301 			return 0;
302 		/* fall through */
303 	case ISCSI_TM_FUNC_TARGET_WARM_RESET:
304 		/*
305 		 * Fail all SCSI cmd PDUs
306 		 */
307 		if (opcode != ISCSI_OP_SCSI_DATA_OUT) {
308 			iscsi_conn_printk(KERN_INFO, conn,
309 					  "task [op %x/%x itt "
310 					  "0x%x/0x%x] "
311 					  "rejected.\n",
312 					  task->hdr->opcode, opcode,
313 					  task->itt, task->hdr_itt);
314 			return -EACCES;
315 		}
316 		/*
317 		 * And also all data-out PDUs in response to R2T
318 		 * if fast_abort is set.
319 		 */
320 		if (conn->session->fast_abort) {
321 			iscsi_conn_printk(KERN_INFO, conn,
322 					  "task [op %x/%x itt "
323 					  "0x%x/0x%x] fast abort.\n",
324 					  task->hdr->opcode, opcode,
325 					  task->itt, task->hdr_itt);
326 			return -EACCES;
327 		}
328 		break;
329 	case ISCSI_TM_FUNC_ABORT_TASK:
330 		/*
331 		 * the caller has already checked if the task
332 		 * they want to abort was in the pending queue so if
333 		 * we are here the cmd pdu has gone out already, and
334 		 * we will only hit this for data-outs
335 		 */
336 		if (opcode == ISCSI_OP_SCSI_DATA_OUT &&
337 		    task->hdr_itt == tmf->rtt) {
338 			ISCSI_DBG_SESSION(conn->session,
339 					  "Preventing task %x/%x from sending "
340 					  "data-out due to abort task in "
341 					  "progress\n", task->itt,
342 					  task->hdr_itt);
343 			return -EACCES;
344 		}
345 		break;
346 	}
347 
348 	return 0;
349 }
350 
351 /**
352  * iscsi_prep_scsi_cmd_pdu - prep iscsi scsi cmd pdu
353  * @task: iscsi task
354  *
355  * Prep basic iSCSI PDU fields for a scsi cmd pdu. The LLD should set
356  * fields like dlength or final based on how much data it sends
357  */
358 static int iscsi_prep_scsi_cmd_pdu(struct iscsi_task *task)
359 {
360 	struct iscsi_conn *conn = task->conn;
361 	struct iscsi_session *session = conn->session;
362 	struct scsi_cmnd *sc = task->sc;
363 	struct iscsi_cmd *hdr;
364 	unsigned hdrlength, cmd_len;
365 	itt_t itt;
366 	int rc;
367 
368 	rc = iscsi_check_tmf_restrictions(task, ISCSI_OP_SCSI_CMD);
369 	if (rc)
370 		return rc;
371 
372 	if (conn->session->tt->alloc_pdu) {
373 		rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_CMD);
374 		if (rc)
375 			return rc;
376 	}
377 	hdr = (struct iscsi_cmd *) task->hdr;
378 	itt = hdr->itt;
379 	memset(hdr, 0, sizeof(*hdr));
380 
381 	if (session->tt->parse_pdu_itt)
382 		hdr->itt = task->hdr_itt = itt;
383 	else
384 		hdr->itt = task->hdr_itt = build_itt(task->itt,
385 						     task->conn->session->age);
386 	task->hdr_len = 0;
387 	rc = iscsi_add_hdr(task, sizeof(*hdr));
388 	if (rc)
389 		return rc;
390 	hdr->opcode = ISCSI_OP_SCSI_CMD;
391 	hdr->flags = ISCSI_ATTR_SIMPLE;
392 	int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
393 	memcpy(task->lun, hdr->lun, sizeof(task->lun));
394 	hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
395 	cmd_len = sc->cmd_len;
396 	if (cmd_len < ISCSI_CDB_SIZE)
397 		memset(&hdr->cdb[cmd_len], 0, ISCSI_CDB_SIZE - cmd_len);
398 	else if (cmd_len > ISCSI_CDB_SIZE) {
399 		rc = iscsi_prep_ecdb_ahs(task);
400 		if (rc)
401 			return rc;
402 		cmd_len = ISCSI_CDB_SIZE;
403 	}
404 	memcpy(hdr->cdb, sc->cmnd, cmd_len);
405 
406 	task->imm_count = 0;
407 	if (scsi_bidi_cmnd(sc)) {
408 		hdr->flags |= ISCSI_FLAG_CMD_READ;
409 		rc = iscsi_prep_bidi_ahs(task);
410 		if (rc)
411 			return rc;
412 	}
413 	if (sc->sc_data_direction == DMA_TO_DEVICE) {
414 		unsigned out_len = scsi_out(sc)->length;
415 		struct iscsi_r2t_info *r2t = &task->unsol_r2t;
416 
417 		hdr->data_length = cpu_to_be32(out_len);
418 		hdr->flags |= ISCSI_FLAG_CMD_WRITE;
419 		/*
420 		 * Write counters:
421 		 *
422 		 *	imm_count	bytes to be sent right after
423 		 *			SCSI PDU Header
424 		 *
425 		 *	unsol_count	bytes(as Data-Out) to be sent
426 		 *			without	R2T ack right after
427 		 *			immediate data
428 		 *
429 		 *	r2t data_length bytes to be sent via R2T ack's
430 		 *
431 		 *      pad_count       bytes to be sent as zero-padding
432 		 */
433 		memset(r2t, 0, sizeof(*r2t));
434 
435 		if (session->imm_data_en) {
436 			if (out_len >= session->first_burst)
437 				task->imm_count = min(session->first_burst,
438 							conn->max_xmit_dlength);
439 			else
440 				task->imm_count = min(out_len,
441 							conn->max_xmit_dlength);
442 			hton24(hdr->dlength, task->imm_count);
443 		} else
444 			zero_data(hdr->dlength);
445 
446 		if (!session->initial_r2t_en) {
447 			r2t->data_length = min(session->first_burst, out_len) -
448 					       task->imm_count;
449 			r2t->data_offset = task->imm_count;
450 			r2t->ttt = cpu_to_be32(ISCSI_RESERVED_TAG);
451 			r2t->exp_statsn = cpu_to_be32(conn->exp_statsn);
452 		}
453 
454 		if (!task->unsol_r2t.data_length)
455 			/* No unsolicit Data-Out's */
456 			hdr->flags |= ISCSI_FLAG_CMD_FINAL;
457 	} else {
458 		hdr->flags |= ISCSI_FLAG_CMD_FINAL;
459 		zero_data(hdr->dlength);
460 		hdr->data_length = cpu_to_be32(scsi_in(sc)->length);
461 
462 		if (sc->sc_data_direction == DMA_FROM_DEVICE)
463 			hdr->flags |= ISCSI_FLAG_CMD_READ;
464 	}
465 
466 	/* calculate size of additional header segments (AHSs) */
467 	hdrlength = task->hdr_len - sizeof(*hdr);
468 
469 	WARN_ON(hdrlength & (ISCSI_PAD_LEN-1));
470 	hdrlength /= ISCSI_PAD_LEN;
471 
472 	WARN_ON(hdrlength >= 256);
473 	hdr->hlength = hdrlength & 0xFF;
474 	hdr->cmdsn = task->cmdsn = cpu_to_be32(session->cmdsn);
475 
476 	if (session->tt->init_task && session->tt->init_task(task))
477 		return -EIO;
478 
479 	task->state = ISCSI_TASK_RUNNING;
480 	session->cmdsn++;
481 
482 	conn->scsicmd_pdus_cnt++;
483 	ISCSI_DBG_SESSION(session, "iscsi prep [%s cid %d sc %p cdb 0x%x "
484 			  "itt 0x%x len %d bidi_len %d cmdsn %d win %d]\n",
485 			  scsi_bidi_cmnd(sc) ? "bidirectional" :
486 			  sc->sc_data_direction == DMA_TO_DEVICE ?
487 			  "write" : "read", conn->id, sc, sc->cmnd[0],
488 			  task->itt, scsi_bufflen(sc),
489 			  scsi_bidi_cmnd(sc) ? scsi_in(sc)->length : 0,
490 			  session->cmdsn,
491 			  session->max_cmdsn - session->exp_cmdsn + 1);
492 	return 0;
493 }
494 
495 /**
496  * iscsi_free_task - free a task
497  * @task: iscsi cmd task
498  *
499  * Must be called with session lock.
500  * This function returns the scsi command to scsi-ml or cleans
501  * up mgmt tasks then returns the task to the pool.
502  */
503 static void iscsi_free_task(struct iscsi_task *task)
504 {
505 	struct iscsi_conn *conn = task->conn;
506 	struct iscsi_session *session = conn->session;
507 	struct scsi_cmnd *sc = task->sc;
508 
509 	ISCSI_DBG_SESSION(session, "freeing task itt 0x%x state %d sc %p\n",
510 			  task->itt, task->state, task->sc);
511 
512 	session->tt->cleanup_task(task);
513 	task->state = ISCSI_TASK_FREE;
514 	task->sc = NULL;
515 	/*
516 	 * login task is preallocated so do not free
517 	 */
518 	if (conn->login_task == task)
519 		return;
520 
521 	kfifo_in(&session->cmdpool.queue, (void*)&task, sizeof(void*));
522 
523 	if (sc) {
524 		task->sc = NULL;
525 		/* SCSI eh reuses commands to verify us */
526 		sc->SCp.ptr = NULL;
527 		/*
528 		 * queue command may call this to free the task, but
529 		 * not have setup the sc callback
530 		 */
531 		if (sc->scsi_done)
532 			sc->scsi_done(sc);
533 	}
534 }
535 
536 void __iscsi_get_task(struct iscsi_task *task)
537 {
538 	atomic_inc(&task->refcount);
539 }
540 EXPORT_SYMBOL_GPL(__iscsi_get_task);
541 
542 static void __iscsi_put_task(struct iscsi_task *task)
543 {
544 	if (atomic_dec_and_test(&task->refcount))
545 		iscsi_free_task(task);
546 }
547 
548 void iscsi_put_task(struct iscsi_task *task)
549 {
550 	struct iscsi_session *session = task->conn->session;
551 
552 	spin_lock_bh(&session->lock);
553 	__iscsi_put_task(task);
554 	spin_unlock_bh(&session->lock);
555 }
556 EXPORT_SYMBOL_GPL(iscsi_put_task);
557 
558 /**
559  * iscsi_complete_task - finish a task
560  * @task: iscsi cmd task
561  * @state: state to complete task with
562  *
563  * Must be called with session lock.
564  */
565 static void iscsi_complete_task(struct iscsi_task *task, int state)
566 {
567 	struct iscsi_conn *conn = task->conn;
568 
569 	ISCSI_DBG_SESSION(conn->session,
570 			  "complete task itt 0x%x state %d sc %p\n",
571 			  task->itt, task->state, task->sc);
572 	if (task->state == ISCSI_TASK_COMPLETED ||
573 	    task->state == ISCSI_TASK_ABRT_TMF ||
574 	    task->state == ISCSI_TASK_ABRT_SESS_RECOV)
575 		return;
576 	WARN_ON_ONCE(task->state == ISCSI_TASK_FREE);
577 	task->state = state;
578 
579 	if (!list_empty(&task->running))
580 		list_del_init(&task->running);
581 
582 	if (conn->task == task)
583 		conn->task = NULL;
584 
585 	if (conn->ping_task == task)
586 		conn->ping_task = NULL;
587 
588 	/* release get from queueing */
589 	__iscsi_put_task(task);
590 }
591 
592 /**
593  * iscsi_complete_scsi_task - finish scsi task normally
594  * @task: iscsi task for scsi cmd
595  * @exp_cmdsn: expected cmd sn in cpu format
596  * @max_cmdsn: max cmd sn in cpu format
597  *
598  * This is used when drivers do not need or cannot perform
599  * lower level pdu processing.
600  *
601  * Called with session lock
602  */
603 void iscsi_complete_scsi_task(struct iscsi_task *task,
604 			      uint32_t exp_cmdsn, uint32_t max_cmdsn)
605 {
606 	struct iscsi_conn *conn = task->conn;
607 
608 	ISCSI_DBG_SESSION(conn->session, "[itt 0x%x]\n", task->itt);
609 
610 	conn->last_recv = jiffies;
611 	__iscsi_update_cmdsn(conn->session, exp_cmdsn, max_cmdsn);
612 	iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
613 }
614 EXPORT_SYMBOL_GPL(iscsi_complete_scsi_task);
615 
616 
617 /*
618  * session lock must be held and if not called for a task that is
619  * still pending or from the xmit thread, then xmit thread must
620  * be suspended.
621  */
622 static void fail_scsi_task(struct iscsi_task *task, int err)
623 {
624 	struct iscsi_conn *conn = task->conn;
625 	struct scsi_cmnd *sc;
626 	int state;
627 
628 	/*
629 	 * if a command completes and we get a successful tmf response
630 	 * we will hit this because the scsi eh abort code does not take
631 	 * a ref to the task.
632 	 */
633 	sc = task->sc;
634 	if (!sc)
635 		return;
636 
637 	if (task->state == ISCSI_TASK_PENDING) {
638 		/*
639 		 * cmd never made it to the xmit thread, so we should not count
640 		 * the cmd in the sequencing
641 		 */
642 		conn->session->queued_cmdsn--;
643 		/* it was never sent so just complete like normal */
644 		state = ISCSI_TASK_COMPLETED;
645 	} else if (err == DID_TRANSPORT_DISRUPTED)
646 		state = ISCSI_TASK_ABRT_SESS_RECOV;
647 	else
648 		state = ISCSI_TASK_ABRT_TMF;
649 
650 	sc->result = err << 16;
651 	if (!scsi_bidi_cmnd(sc))
652 		scsi_set_resid(sc, scsi_bufflen(sc));
653 	else {
654 		scsi_out(sc)->resid = scsi_out(sc)->length;
655 		scsi_in(sc)->resid = scsi_in(sc)->length;
656 	}
657 
658 	iscsi_complete_task(task, state);
659 }
660 
661 static int iscsi_prep_mgmt_task(struct iscsi_conn *conn,
662 				struct iscsi_task *task)
663 {
664 	struct iscsi_session *session = conn->session;
665 	struct iscsi_hdr *hdr = task->hdr;
666 	struct iscsi_nopout *nop = (struct iscsi_nopout *)hdr;
667 	uint8_t opcode = hdr->opcode & ISCSI_OPCODE_MASK;
668 
669 	if (conn->session->state == ISCSI_STATE_LOGGING_OUT)
670 		return -ENOTCONN;
671 
672 	if (opcode != ISCSI_OP_LOGIN && opcode != ISCSI_OP_TEXT)
673 		nop->exp_statsn = cpu_to_be32(conn->exp_statsn);
674 	/*
675 	 * pre-format CmdSN for outgoing PDU.
676 	 */
677 	nop->cmdsn = cpu_to_be32(session->cmdsn);
678 	if (hdr->itt != RESERVED_ITT) {
679 		/*
680 		 * TODO: We always use immediate for normal session pdus.
681 		 * If we start to send tmfs or nops as non-immediate then
682 		 * we should start checking the cmdsn numbers for mgmt tasks.
683 		 *
684 		 * During discovery sessions iscsid sends TEXT as non immediate,
685 		 * but we always only send one PDU at a time.
686 		 */
687 		if (conn->c_stage == ISCSI_CONN_STARTED &&
688 		    !(hdr->opcode & ISCSI_OP_IMMEDIATE)) {
689 			session->queued_cmdsn++;
690 			session->cmdsn++;
691 		}
692 	}
693 
694 	if (session->tt->init_task && session->tt->init_task(task))
695 		return -EIO;
696 
697 	if ((hdr->opcode & ISCSI_OPCODE_MASK) == ISCSI_OP_LOGOUT)
698 		session->state = ISCSI_STATE_LOGGING_OUT;
699 
700 	task->state = ISCSI_TASK_RUNNING;
701 	ISCSI_DBG_SESSION(session, "mgmtpdu [op 0x%x hdr->itt 0x%x "
702 			  "datalen %d]\n", hdr->opcode & ISCSI_OPCODE_MASK,
703 			  hdr->itt, task->data_count);
704 	return 0;
705 }
706 
707 static struct iscsi_task *
708 __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
709 		      char *data, uint32_t data_size)
710 {
711 	struct iscsi_session *session = conn->session;
712 	struct iscsi_host *ihost = shost_priv(session->host);
713 	uint8_t opcode = hdr->opcode & ISCSI_OPCODE_MASK;
714 	struct iscsi_task *task;
715 	itt_t itt;
716 
717 	if (session->state == ISCSI_STATE_TERMINATE)
718 		return NULL;
719 
720 	if (opcode == ISCSI_OP_LOGIN || opcode == ISCSI_OP_TEXT) {
721 		/*
722 		 * Login and Text are sent serially, in
723 		 * request-followed-by-response sequence.
724 		 * Same task can be used. Same ITT must be used.
725 		 * Note that login_task is preallocated at conn_create().
726 		 */
727 		if (conn->login_task->state != ISCSI_TASK_FREE) {
728 			iscsi_conn_printk(KERN_ERR, conn, "Login/Text in "
729 					  "progress. Cannot start new task.\n");
730 			return NULL;
731 		}
732 
733 		task = conn->login_task;
734 	} else {
735 		if (session->state != ISCSI_STATE_LOGGED_IN)
736 			return NULL;
737 
738 		BUG_ON(conn->c_stage == ISCSI_CONN_INITIAL_STAGE);
739 		BUG_ON(conn->c_stage == ISCSI_CONN_STOPPED);
740 
741 		if (!kfifo_out(&session->cmdpool.queue,
742 				 (void*)&task, sizeof(void*)))
743 			return NULL;
744 	}
745 	/*
746 	 * released in complete pdu for task we expect a response for, and
747 	 * released by the lld when it has transmitted the task for
748 	 * pdus we do not expect a response for.
749 	 */
750 	atomic_set(&task->refcount, 1);
751 	task->conn = conn;
752 	task->sc = NULL;
753 	INIT_LIST_HEAD(&task->running);
754 	task->state = ISCSI_TASK_PENDING;
755 
756 	if (data_size) {
757 		memcpy(task->data, data, data_size);
758 		task->data_count = data_size;
759 	} else
760 		task->data_count = 0;
761 
762 	if (conn->session->tt->alloc_pdu) {
763 		if (conn->session->tt->alloc_pdu(task, hdr->opcode)) {
764 			iscsi_conn_printk(KERN_ERR, conn, "Could not allocate "
765 					 "pdu for mgmt task.\n");
766 			goto free_task;
767 		}
768 	}
769 
770 	itt = task->hdr->itt;
771 	task->hdr_len = sizeof(struct iscsi_hdr);
772 	memcpy(task->hdr, hdr, sizeof(struct iscsi_hdr));
773 
774 	if (hdr->itt != RESERVED_ITT) {
775 		if (session->tt->parse_pdu_itt)
776 			task->hdr->itt = itt;
777 		else
778 			task->hdr->itt = build_itt(task->itt,
779 						   task->conn->session->age);
780 	}
781 
782 	if (!ihost->workq) {
783 		if (iscsi_prep_mgmt_task(conn, task))
784 			goto free_task;
785 
786 		if (session->tt->xmit_task(task))
787 			goto free_task;
788 	} else {
789 		list_add_tail(&task->running, &conn->mgmtqueue);
790 		iscsi_conn_queue_work(conn);
791 	}
792 
793 	return task;
794 
795 free_task:
796 	__iscsi_put_task(task);
797 	return NULL;
798 }
799 
800 int iscsi_conn_send_pdu(struct iscsi_cls_conn *cls_conn, struct iscsi_hdr *hdr,
801 			char *data, uint32_t data_size)
802 {
803 	struct iscsi_conn *conn = cls_conn->dd_data;
804 	struct iscsi_session *session = conn->session;
805 	int err = 0;
806 
807 	spin_lock_bh(&session->lock);
808 	if (!__iscsi_conn_send_pdu(conn, hdr, data, data_size))
809 		err = -EPERM;
810 	spin_unlock_bh(&session->lock);
811 	return err;
812 }
813 EXPORT_SYMBOL_GPL(iscsi_conn_send_pdu);
814 
815 /**
816  * iscsi_cmd_rsp - SCSI Command Response processing
817  * @conn: iscsi connection
818  * @hdr: iscsi header
819  * @task: scsi command task
820  * @data: cmd data buffer
821  * @datalen: len of buffer
822  *
823  * iscsi_cmd_rsp sets up the scsi_cmnd fields based on the PDU and
824  * then completes the command and task.
825  **/
826 static void iscsi_scsi_cmd_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
827 			       struct iscsi_task *task, char *data,
828 			       int datalen)
829 {
830 	struct iscsi_cmd_rsp *rhdr = (struct iscsi_cmd_rsp *)hdr;
831 	struct iscsi_session *session = conn->session;
832 	struct scsi_cmnd *sc = task->sc;
833 
834 	iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
835 	conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
836 
837 	sc->result = (DID_OK << 16) | rhdr->cmd_status;
838 
839 	if (rhdr->response != ISCSI_STATUS_CMD_COMPLETED) {
840 		sc->result = DID_ERROR << 16;
841 		goto out;
842 	}
843 
844 	if (rhdr->cmd_status == SAM_STAT_CHECK_CONDITION) {
845 		uint16_t senselen;
846 
847 		if (datalen < 2) {
848 invalid_datalen:
849 			iscsi_conn_printk(KERN_ERR,  conn,
850 					 "Got CHECK_CONDITION but invalid data "
851 					 "buffer size of %d\n", datalen);
852 			sc->result = DID_BAD_TARGET << 16;
853 			goto out;
854 		}
855 
856 		senselen = get_unaligned_be16(data);
857 		if (datalen < senselen)
858 			goto invalid_datalen;
859 
860 		memcpy(sc->sense_buffer, data + 2,
861 		       min_t(uint16_t, senselen, SCSI_SENSE_BUFFERSIZE));
862 		ISCSI_DBG_SESSION(session, "copied %d bytes of sense\n",
863 				  min_t(uint16_t, senselen,
864 				  SCSI_SENSE_BUFFERSIZE));
865 	}
866 
867 	if (rhdr->flags & (ISCSI_FLAG_CMD_BIDI_UNDERFLOW |
868 			   ISCSI_FLAG_CMD_BIDI_OVERFLOW)) {
869 		int res_count = be32_to_cpu(rhdr->bi_residual_count);
870 
871 		if (scsi_bidi_cmnd(sc) && res_count > 0 &&
872 				(rhdr->flags & ISCSI_FLAG_CMD_BIDI_OVERFLOW ||
873 				 res_count <= scsi_in(sc)->length))
874 			scsi_in(sc)->resid = res_count;
875 		else
876 			sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
877 	}
878 
879 	if (rhdr->flags & (ISCSI_FLAG_CMD_UNDERFLOW |
880 	                   ISCSI_FLAG_CMD_OVERFLOW)) {
881 		int res_count = be32_to_cpu(rhdr->residual_count);
882 
883 		if (res_count > 0 &&
884 		    (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
885 		     res_count <= scsi_bufflen(sc)))
886 			/* write side for bidi or uni-io set_resid */
887 			scsi_set_resid(sc, res_count);
888 		else
889 			sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
890 	}
891 out:
892 	ISCSI_DBG_SESSION(session, "cmd rsp done [sc %p res %d itt 0x%x]\n",
893 			  sc, sc->result, task->itt);
894 	conn->scsirsp_pdus_cnt++;
895 	iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
896 }
897 
898 /**
899  * iscsi_data_in_rsp - SCSI Data-In Response processing
900  * @conn: iscsi connection
901  * @hdr:  iscsi pdu
902  * @task: scsi command task
903  **/
904 static void
905 iscsi_data_in_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
906 		  struct iscsi_task *task)
907 {
908 	struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)hdr;
909 	struct scsi_cmnd *sc = task->sc;
910 
911 	if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
912 		return;
913 
914 	iscsi_update_cmdsn(conn->session, (struct iscsi_nopin *)hdr);
915 	sc->result = (DID_OK << 16) | rhdr->cmd_status;
916 	conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
917 	if (rhdr->flags & (ISCSI_FLAG_DATA_UNDERFLOW |
918 	                   ISCSI_FLAG_DATA_OVERFLOW)) {
919 		int res_count = be32_to_cpu(rhdr->residual_count);
920 
921 		if (res_count > 0 &&
922 		    (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
923 		     res_count <= scsi_in(sc)->length))
924 			scsi_in(sc)->resid = res_count;
925 		else
926 			sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
927 	}
928 
929 	ISCSI_DBG_SESSION(conn->session, "data in with status done "
930 			  "[sc %p res %d itt 0x%x]\n",
931 			  sc, sc->result, task->itt);
932 	conn->scsirsp_pdus_cnt++;
933 	iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
934 }
935 
936 static void iscsi_tmf_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
937 {
938 	struct iscsi_tm_rsp *tmf = (struct iscsi_tm_rsp *)hdr;
939 
940 	conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
941 	conn->tmfrsp_pdus_cnt++;
942 
943 	if (conn->tmf_state != TMF_QUEUED)
944 		return;
945 
946 	if (tmf->response == ISCSI_TMF_RSP_COMPLETE)
947 		conn->tmf_state = TMF_SUCCESS;
948 	else if (tmf->response == ISCSI_TMF_RSP_NO_TASK)
949 		conn->tmf_state = TMF_NOT_FOUND;
950 	else
951 		conn->tmf_state = TMF_FAILED;
952 	wake_up(&conn->ehwait);
953 }
954 
955 static void iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
956 {
957         struct iscsi_nopout hdr;
958 	struct iscsi_task *task;
959 
960 	if (!rhdr && conn->ping_task)
961 		return;
962 
963 	memset(&hdr, 0, sizeof(struct iscsi_nopout));
964 	hdr.opcode = ISCSI_OP_NOOP_OUT | ISCSI_OP_IMMEDIATE;
965 	hdr.flags = ISCSI_FLAG_CMD_FINAL;
966 
967 	if (rhdr) {
968 		memcpy(hdr.lun, rhdr->lun, 8);
969 		hdr.ttt = rhdr->ttt;
970 		hdr.itt = RESERVED_ITT;
971 	} else
972 		hdr.ttt = RESERVED_ITT;
973 
974 	task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)&hdr, NULL, 0);
975 	if (!task)
976 		iscsi_conn_printk(KERN_ERR, conn, "Could not send nopout\n");
977 	else if (!rhdr) {
978 		/* only track our nops */
979 		conn->ping_task = task;
980 		conn->last_ping = jiffies;
981 	}
982 }
983 
984 static int iscsi_nop_out_rsp(struct iscsi_task *task,
985 			     struct iscsi_nopin *nop, char *data, int datalen)
986 {
987 	struct iscsi_conn *conn = task->conn;
988 	int rc = 0;
989 
990 	if (conn->ping_task != task) {
991 		/*
992 		 * If this is not in response to one of our
993 		 * nops then it must be from userspace.
994 		 */
995 		if (iscsi_recv_pdu(conn->cls_conn, (struct iscsi_hdr *)nop,
996 				   data, datalen))
997 			rc = ISCSI_ERR_CONN_FAILED;
998 	} else
999 		mod_timer(&conn->transport_timer, jiffies + conn->recv_timeout);
1000 	iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
1001 	return rc;
1002 }
1003 
1004 static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
1005 			       char *data, int datalen)
1006 {
1007 	struct iscsi_reject *reject = (struct iscsi_reject *)hdr;
1008 	struct iscsi_hdr rejected_pdu;
1009 	int opcode, rc = 0;
1010 
1011 	conn->exp_statsn = be32_to_cpu(reject->statsn) + 1;
1012 
1013 	if (ntoh24(reject->dlength) > datalen ||
1014 	    ntoh24(reject->dlength) < sizeof(struct iscsi_hdr)) {
1015 		iscsi_conn_printk(KERN_ERR, conn, "Cannot handle rejected "
1016 				  "pdu. Invalid data length (pdu dlength "
1017 				  "%u, datalen %d\n", ntoh24(reject->dlength),
1018 				  datalen);
1019 		return ISCSI_ERR_PROTO;
1020 	}
1021 	memcpy(&rejected_pdu, data, sizeof(struct iscsi_hdr));
1022 	opcode = rejected_pdu.opcode & ISCSI_OPCODE_MASK;
1023 
1024 	switch (reject->reason) {
1025 	case ISCSI_REASON_DATA_DIGEST_ERROR:
1026 		iscsi_conn_printk(KERN_ERR, conn,
1027 				  "pdu (op 0x%x itt 0x%x) rejected "
1028 				  "due to DataDigest error.\n",
1029 				  rejected_pdu.itt, opcode);
1030 		break;
1031 	case ISCSI_REASON_IMM_CMD_REJECT:
1032 		iscsi_conn_printk(KERN_ERR, conn,
1033 				  "pdu (op 0x%x itt 0x%x) rejected. Too many "
1034 				  "immediate commands.\n",
1035 				  rejected_pdu.itt, opcode);
1036 		/*
1037 		 * We only send one TMF at a time so if the target could not
1038 		 * handle it, then it should get fixed (RFC mandates that
1039 		 * a target can handle one immediate TMF per conn).
1040 		 *
1041 		 * For nops-outs, we could have sent more than one if
1042 		 * the target is sending us lots of nop-ins
1043 		 */
1044 		if (opcode != ISCSI_OP_NOOP_OUT)
1045 			return 0;
1046 
1047 		 if (rejected_pdu.itt == cpu_to_be32(ISCSI_RESERVED_TAG))
1048 			/*
1049 			 * nop-out in response to target's nop-out rejected.
1050 			 * Just resend.
1051 			 */
1052 			iscsi_send_nopout(conn,
1053 					  (struct iscsi_nopin*)&rejected_pdu);
1054 		else {
1055 			struct iscsi_task *task;
1056 			/*
1057 			 * Our nop as ping got dropped. We know the target
1058 			 * and transport are ok so just clean up
1059 			 */
1060 			task = iscsi_itt_to_task(conn, rejected_pdu.itt);
1061 			if (!task) {
1062 				iscsi_conn_printk(KERN_ERR, conn,
1063 						 "Invalid pdu reject. Could "
1064 						 "not lookup rejected task.\n");
1065 				rc = ISCSI_ERR_BAD_ITT;
1066 			} else
1067 				rc = iscsi_nop_out_rsp(task,
1068 					(struct iscsi_nopin*)&rejected_pdu,
1069 					NULL, 0);
1070 		}
1071 		break;
1072 	default:
1073 		iscsi_conn_printk(KERN_ERR, conn,
1074 				  "pdu (op 0x%x itt 0x%x) rejected. Reason "
1075 				  "code 0x%x\n", rejected_pdu.itt,
1076 				  rejected_pdu.opcode, reject->reason);
1077 		break;
1078 	}
1079 	return rc;
1080 }
1081 
1082 /**
1083  * iscsi_itt_to_task - look up task by itt
1084  * @conn: iscsi connection
1085  * @itt: itt
1086  *
1087  * This should be used for mgmt tasks like login and nops, or if
1088  * the LDD's itt space does not include the session age.
1089  *
1090  * The session lock must be held.
1091  */
1092 struct iscsi_task *iscsi_itt_to_task(struct iscsi_conn *conn, itt_t itt)
1093 {
1094 	struct iscsi_session *session = conn->session;
1095 	int i;
1096 
1097 	if (itt == RESERVED_ITT)
1098 		return NULL;
1099 
1100 	if (session->tt->parse_pdu_itt)
1101 		session->tt->parse_pdu_itt(conn, itt, &i, NULL);
1102 	else
1103 		i = get_itt(itt);
1104 	if (i >= session->cmds_max)
1105 		return NULL;
1106 
1107 	return session->cmds[i];
1108 }
1109 EXPORT_SYMBOL_GPL(iscsi_itt_to_task);
1110 
1111 /**
1112  * __iscsi_complete_pdu - complete pdu
1113  * @conn: iscsi conn
1114  * @hdr: iscsi header
1115  * @data: data buffer
1116  * @datalen: len of data buffer
1117  *
1118  * Completes pdu processing by freeing any resources allocated at
1119  * queuecommand or send generic. session lock must be held and verify
1120  * itt must have been called.
1121  */
1122 int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
1123 			 char *data, int datalen)
1124 {
1125 	struct iscsi_session *session = conn->session;
1126 	int opcode = hdr->opcode & ISCSI_OPCODE_MASK, rc = 0;
1127 	struct iscsi_task *task;
1128 	uint32_t itt;
1129 
1130 	conn->last_recv = jiffies;
1131 	rc = iscsi_verify_itt(conn, hdr->itt);
1132 	if (rc)
1133 		return rc;
1134 
1135 	if (hdr->itt != RESERVED_ITT)
1136 		itt = get_itt(hdr->itt);
1137 	else
1138 		itt = ~0U;
1139 
1140 	ISCSI_DBG_SESSION(session, "[op 0x%x cid %d itt 0x%x len %d]\n",
1141 			  opcode, conn->id, itt, datalen);
1142 
1143 	if (itt == ~0U) {
1144 		iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
1145 
1146 		switch(opcode) {
1147 		case ISCSI_OP_NOOP_IN:
1148 			if (datalen) {
1149 				rc = ISCSI_ERR_PROTO;
1150 				break;
1151 			}
1152 
1153 			if (hdr->ttt == cpu_to_be32(ISCSI_RESERVED_TAG))
1154 				break;
1155 
1156 			iscsi_send_nopout(conn, (struct iscsi_nopin*)hdr);
1157 			break;
1158 		case ISCSI_OP_REJECT:
1159 			rc = iscsi_handle_reject(conn, hdr, data, datalen);
1160 			break;
1161 		case ISCSI_OP_ASYNC_EVENT:
1162 			conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
1163 			if (iscsi_recv_pdu(conn->cls_conn, hdr, data, datalen))
1164 				rc = ISCSI_ERR_CONN_FAILED;
1165 			break;
1166 		default:
1167 			rc = ISCSI_ERR_BAD_OPCODE;
1168 			break;
1169 		}
1170 		goto out;
1171 	}
1172 
1173 	switch(opcode) {
1174 	case ISCSI_OP_SCSI_CMD_RSP:
1175 	case ISCSI_OP_SCSI_DATA_IN:
1176 		task = iscsi_itt_to_ctask(conn, hdr->itt);
1177 		if (!task)
1178 			return ISCSI_ERR_BAD_ITT;
1179 		task->last_xfer = jiffies;
1180 		break;
1181 	case ISCSI_OP_R2T:
1182 		/*
1183 		 * LLD handles R2Ts if they need to.
1184 		 */
1185 		return 0;
1186 	case ISCSI_OP_LOGOUT_RSP:
1187 	case ISCSI_OP_LOGIN_RSP:
1188 	case ISCSI_OP_TEXT_RSP:
1189 	case ISCSI_OP_SCSI_TMFUNC_RSP:
1190 	case ISCSI_OP_NOOP_IN:
1191 		task = iscsi_itt_to_task(conn, hdr->itt);
1192 		if (!task)
1193 			return ISCSI_ERR_BAD_ITT;
1194 		break;
1195 	default:
1196 		return ISCSI_ERR_BAD_OPCODE;
1197 	}
1198 
1199 	switch(opcode) {
1200 	case ISCSI_OP_SCSI_CMD_RSP:
1201 		iscsi_scsi_cmd_rsp(conn, hdr, task, data, datalen);
1202 		break;
1203 	case ISCSI_OP_SCSI_DATA_IN:
1204 		iscsi_data_in_rsp(conn, hdr, task);
1205 		break;
1206 	case ISCSI_OP_LOGOUT_RSP:
1207 		iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
1208 		if (datalen) {
1209 			rc = ISCSI_ERR_PROTO;
1210 			break;
1211 		}
1212 		conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
1213 		goto recv_pdu;
1214 	case ISCSI_OP_LOGIN_RSP:
1215 	case ISCSI_OP_TEXT_RSP:
1216 		iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
1217 		/*
1218 		 * login related PDU's exp_statsn is handled in
1219 		 * userspace
1220 		 */
1221 		goto recv_pdu;
1222 	case ISCSI_OP_SCSI_TMFUNC_RSP:
1223 		iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
1224 		if (datalen) {
1225 			rc = ISCSI_ERR_PROTO;
1226 			break;
1227 		}
1228 
1229 		iscsi_tmf_rsp(conn, hdr);
1230 		iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
1231 		break;
1232 	case ISCSI_OP_NOOP_IN:
1233 		iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
1234 		if (hdr->ttt != cpu_to_be32(ISCSI_RESERVED_TAG) || datalen) {
1235 			rc = ISCSI_ERR_PROTO;
1236 			break;
1237 		}
1238 		conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
1239 
1240 		rc = iscsi_nop_out_rsp(task, (struct iscsi_nopin*)hdr,
1241 				       data, datalen);
1242 		break;
1243 	default:
1244 		rc = ISCSI_ERR_BAD_OPCODE;
1245 		break;
1246 	}
1247 
1248 out:
1249 	return rc;
1250 recv_pdu:
1251 	if (iscsi_recv_pdu(conn->cls_conn, hdr, data, datalen))
1252 		rc = ISCSI_ERR_CONN_FAILED;
1253 	iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
1254 	return rc;
1255 }
1256 EXPORT_SYMBOL_GPL(__iscsi_complete_pdu);
1257 
1258 int iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
1259 		       char *data, int datalen)
1260 {
1261 	int rc;
1262 
1263 	spin_lock(&conn->session->lock);
1264 	rc = __iscsi_complete_pdu(conn, hdr, data, datalen);
1265 	spin_unlock(&conn->session->lock);
1266 	return rc;
1267 }
1268 EXPORT_SYMBOL_GPL(iscsi_complete_pdu);
1269 
1270 int iscsi_verify_itt(struct iscsi_conn *conn, itt_t itt)
1271 {
1272 	struct iscsi_session *session = conn->session;
1273 	int age = 0, i = 0;
1274 
1275 	if (itt == RESERVED_ITT)
1276 		return 0;
1277 
1278 	if (session->tt->parse_pdu_itt)
1279 		session->tt->parse_pdu_itt(conn, itt, &i, &age);
1280 	else {
1281 		i = get_itt(itt);
1282 		age = ((__force u32)itt >> ISCSI_AGE_SHIFT) & ISCSI_AGE_MASK;
1283 	}
1284 
1285 	if (age != session->age) {
1286 		iscsi_conn_printk(KERN_ERR, conn,
1287 				  "received itt %x expected session age (%x)\n",
1288 				  (__force u32)itt, session->age);
1289 		return ISCSI_ERR_BAD_ITT;
1290 	}
1291 
1292 	if (i >= session->cmds_max) {
1293 		iscsi_conn_printk(KERN_ERR, conn,
1294 				  "received invalid itt index %u (max cmds "
1295 				   "%u.\n", i, session->cmds_max);
1296 		return ISCSI_ERR_BAD_ITT;
1297 	}
1298 	return 0;
1299 }
1300 EXPORT_SYMBOL_GPL(iscsi_verify_itt);
1301 
1302 /**
1303  * iscsi_itt_to_ctask - look up ctask by itt
1304  * @conn: iscsi connection
1305  * @itt: itt
1306  *
1307  * This should be used for cmd tasks.
1308  *
1309  * The session lock must be held.
1310  */
1311 struct iscsi_task *iscsi_itt_to_ctask(struct iscsi_conn *conn, itt_t itt)
1312 {
1313 	struct iscsi_task *task;
1314 
1315 	if (iscsi_verify_itt(conn, itt))
1316 		return NULL;
1317 
1318 	task = iscsi_itt_to_task(conn, itt);
1319 	if (!task || !task->sc)
1320 		return NULL;
1321 
1322 	if (task->sc->SCp.phase != conn->session->age) {
1323 		iscsi_session_printk(KERN_ERR, conn->session,
1324 				  "task's session age %d, expected %d\n",
1325 				  task->sc->SCp.phase, conn->session->age);
1326 		return NULL;
1327 	}
1328 
1329 	return task;
1330 }
1331 EXPORT_SYMBOL_GPL(iscsi_itt_to_ctask);
1332 
1333 void iscsi_session_failure(struct iscsi_session *session,
1334 			   enum iscsi_err err)
1335 {
1336 	struct iscsi_conn *conn;
1337 	struct device *dev;
1338 	unsigned long flags;
1339 
1340 	spin_lock_irqsave(&session->lock, flags);
1341 	conn = session->leadconn;
1342 	if (session->state == ISCSI_STATE_TERMINATE || !conn) {
1343 		spin_unlock_irqrestore(&session->lock, flags);
1344 		return;
1345 	}
1346 
1347 	dev = get_device(&conn->cls_conn->dev);
1348 	spin_unlock_irqrestore(&session->lock, flags);
1349 	if (!dev)
1350 	        return;
1351 	/*
1352 	 * if the host is being removed bypass the connection
1353 	 * recovery initialization because we are going to kill
1354 	 * the session.
1355 	 */
1356 	if (err == ISCSI_ERR_INVALID_HOST)
1357 		iscsi_conn_error_event(conn->cls_conn, err);
1358 	else
1359 		iscsi_conn_failure(conn, err);
1360 	put_device(dev);
1361 }
1362 EXPORT_SYMBOL_GPL(iscsi_session_failure);
1363 
1364 void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
1365 {
1366 	struct iscsi_session *session = conn->session;
1367 	unsigned long flags;
1368 
1369 	spin_lock_irqsave(&session->lock, flags);
1370 	if (session->state == ISCSI_STATE_FAILED) {
1371 		spin_unlock_irqrestore(&session->lock, flags);
1372 		return;
1373 	}
1374 
1375 	if (conn->stop_stage == 0)
1376 		session->state = ISCSI_STATE_FAILED;
1377 	spin_unlock_irqrestore(&session->lock, flags);
1378 
1379 	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
1380 	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
1381 	iscsi_conn_error_event(conn->cls_conn, err);
1382 }
1383 EXPORT_SYMBOL_GPL(iscsi_conn_failure);
1384 
1385 static int iscsi_check_cmdsn_window_closed(struct iscsi_conn *conn)
1386 {
1387 	struct iscsi_session *session = conn->session;
1388 
1389 	/*
1390 	 * Check for iSCSI window and take care of CmdSN wrap-around
1391 	 */
1392 	if (!iscsi_sna_lte(session->queued_cmdsn, session->max_cmdsn)) {
1393 		ISCSI_DBG_SESSION(session, "iSCSI CmdSN closed. ExpCmdSn "
1394 				  "%u MaxCmdSN %u CmdSN %u/%u\n",
1395 				  session->exp_cmdsn, session->max_cmdsn,
1396 				  session->cmdsn, session->queued_cmdsn);
1397 		return -ENOSPC;
1398 	}
1399 	return 0;
1400 }
1401 
1402 static int iscsi_xmit_task(struct iscsi_conn *conn)
1403 {
1404 	struct iscsi_task *task = conn->task;
1405 	int rc;
1406 
1407 	if (test_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx))
1408 		return -ENODATA;
1409 
1410 	__iscsi_get_task(task);
1411 	spin_unlock_bh(&conn->session->lock);
1412 	rc = conn->session->tt->xmit_task(task);
1413 	spin_lock_bh(&conn->session->lock);
1414 	if (!rc) {
1415 		/* done with this task */
1416 		task->last_xfer = jiffies;
1417 		conn->task = NULL;
1418 	}
1419 	__iscsi_put_task(task);
1420 	return rc;
1421 }
1422 
1423 /**
1424  * iscsi_requeue_task - requeue task to run from session workqueue
1425  * @task: task to requeue
1426  *
1427  * LLDs that need to run a task from the session workqueue should call
1428  * this. The session lock must be held. This should only be called
1429  * by software drivers.
1430  */
1431 void iscsi_requeue_task(struct iscsi_task *task)
1432 {
1433 	struct iscsi_conn *conn = task->conn;
1434 
1435 	/*
1436 	 * this may be on the requeue list already if the xmit_task callout
1437 	 * is handling the r2ts while we are adding new ones
1438 	 */
1439 	if (list_empty(&task->running))
1440 		list_add_tail(&task->running, &conn->requeue);
1441 	iscsi_conn_queue_work(conn);
1442 }
1443 EXPORT_SYMBOL_GPL(iscsi_requeue_task);
1444 
1445 /**
1446  * iscsi_data_xmit - xmit any command into the scheduled connection
1447  * @conn: iscsi connection
1448  *
1449  * Notes:
1450  *	The function can return -EAGAIN in which case the caller must
1451  *	re-schedule it again later or recover. '0' return code means
1452  *	successful xmit.
1453  **/
1454 static int iscsi_data_xmit(struct iscsi_conn *conn)
1455 {
1456 	struct iscsi_task *task;
1457 	int rc = 0;
1458 
1459 	spin_lock_bh(&conn->session->lock);
1460 	if (test_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx)) {
1461 		ISCSI_DBG_SESSION(conn->session, "Tx suspended!\n");
1462 		spin_unlock_bh(&conn->session->lock);
1463 		return -ENODATA;
1464 	}
1465 
1466 	if (conn->task) {
1467 		rc = iscsi_xmit_task(conn);
1468 	        if (rc)
1469 		        goto done;
1470 	}
1471 
1472 	/*
1473 	 * process mgmt pdus like nops before commands since we should
1474 	 * only have one nop-out as a ping from us and targets should not
1475 	 * overflow us with nop-ins
1476 	 */
1477 check_mgmt:
1478 	while (!list_empty(&conn->mgmtqueue)) {
1479 		conn->task = list_entry(conn->mgmtqueue.next,
1480 					 struct iscsi_task, running);
1481 		list_del_init(&conn->task->running);
1482 		if (iscsi_prep_mgmt_task(conn, conn->task)) {
1483 			__iscsi_put_task(conn->task);
1484 			conn->task = NULL;
1485 			continue;
1486 		}
1487 		rc = iscsi_xmit_task(conn);
1488 		if (rc)
1489 			goto done;
1490 	}
1491 
1492 	/* process pending command queue */
1493 	while (!list_empty(&conn->cmdqueue)) {
1494 		conn->task = list_entry(conn->cmdqueue.next, struct iscsi_task,
1495 					running);
1496 		list_del_init(&conn->task->running);
1497 		if (conn->session->state == ISCSI_STATE_LOGGING_OUT) {
1498 			fail_scsi_task(conn->task, DID_IMM_RETRY);
1499 			continue;
1500 		}
1501 		rc = iscsi_prep_scsi_cmd_pdu(conn->task);
1502 		if (rc) {
1503 			if (rc == -ENOMEM || rc == -EACCES) {
1504 				list_add_tail(&conn->task->running,
1505 					      &conn->cmdqueue);
1506 				conn->task = NULL;
1507 				goto done;
1508 			} else
1509 				fail_scsi_task(conn->task, DID_ABORT);
1510 			continue;
1511 		}
1512 		rc = iscsi_xmit_task(conn);
1513 		if (rc)
1514 			goto done;
1515 		/*
1516 		 * we could continuously get new task requests so
1517 		 * we need to check the mgmt queue for nops that need to
1518 		 * be sent to aviod starvation
1519 		 */
1520 		if (!list_empty(&conn->mgmtqueue))
1521 			goto check_mgmt;
1522 	}
1523 
1524 	while (!list_empty(&conn->requeue)) {
1525 		/*
1526 		 * we always do fastlogout - conn stop code will clean up.
1527 		 */
1528 		if (conn->session->state == ISCSI_STATE_LOGGING_OUT)
1529 			break;
1530 
1531 		task = list_entry(conn->requeue.next, struct iscsi_task,
1532 				  running);
1533 		if (iscsi_check_tmf_restrictions(task, ISCSI_OP_SCSI_DATA_OUT))
1534 			break;
1535 
1536 		conn->task = task;
1537 		list_del_init(&conn->task->running);
1538 		conn->task->state = ISCSI_TASK_RUNNING;
1539 		rc = iscsi_xmit_task(conn);
1540 		if (rc)
1541 			goto done;
1542 		if (!list_empty(&conn->mgmtqueue))
1543 			goto check_mgmt;
1544 	}
1545 	spin_unlock_bh(&conn->session->lock);
1546 	return -ENODATA;
1547 
1548 done:
1549 	spin_unlock_bh(&conn->session->lock);
1550 	return rc;
1551 }
1552 
1553 static void iscsi_xmitworker(struct work_struct *work)
1554 {
1555 	struct iscsi_conn *conn =
1556 		container_of(work, struct iscsi_conn, xmitwork);
1557 	int rc;
1558 	/*
1559 	 * serialize Xmit worker on a per-connection basis.
1560 	 */
1561 	do {
1562 		rc = iscsi_data_xmit(conn);
1563 	} while (rc >= 0 || rc == -EAGAIN);
1564 }
1565 
1566 static inline struct iscsi_task *iscsi_alloc_task(struct iscsi_conn *conn,
1567 						  struct scsi_cmnd *sc)
1568 {
1569 	struct iscsi_task *task;
1570 
1571 	if (!kfifo_out(&conn->session->cmdpool.queue,
1572 			 (void *) &task, sizeof(void *)))
1573 		return NULL;
1574 
1575 	sc->SCp.phase = conn->session->age;
1576 	sc->SCp.ptr = (char *) task;
1577 
1578 	atomic_set(&task->refcount, 1);
1579 	task->state = ISCSI_TASK_PENDING;
1580 	task->conn = conn;
1581 	task->sc = sc;
1582 	task->have_checked_conn = false;
1583 	task->last_timeout = jiffies;
1584 	task->last_xfer = jiffies;
1585 	INIT_LIST_HEAD(&task->running);
1586 	return task;
1587 }
1588 
1589 enum {
1590 	FAILURE_BAD_HOST = 1,
1591 	FAILURE_SESSION_FAILED,
1592 	FAILURE_SESSION_FREED,
1593 	FAILURE_WINDOW_CLOSED,
1594 	FAILURE_OOM,
1595 	FAILURE_SESSION_TERMINATE,
1596 	FAILURE_SESSION_IN_RECOVERY,
1597 	FAILURE_SESSION_RECOVERY_TIMEOUT,
1598 	FAILURE_SESSION_LOGGING_OUT,
1599 	FAILURE_SESSION_NOT_READY,
1600 };
1601 
1602 static int iscsi_queuecommand_lck(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
1603 {
1604 	struct iscsi_cls_session *cls_session;
1605 	struct Scsi_Host *host;
1606 	struct iscsi_host *ihost;
1607 	int reason = 0;
1608 	struct iscsi_session *session;
1609 	struct iscsi_conn *conn;
1610 	struct iscsi_task *task = NULL;
1611 
1612 	sc->scsi_done = done;
1613 	sc->result = 0;
1614 	sc->SCp.ptr = NULL;
1615 
1616 	host = sc->device->host;
1617 	ihost = shost_priv(host);
1618 	spin_unlock(host->host_lock);
1619 
1620 	cls_session = starget_to_session(scsi_target(sc->device));
1621 	session = cls_session->dd_data;
1622 	spin_lock(&session->lock);
1623 
1624 	reason = iscsi_session_chkready(cls_session);
1625 	if (reason) {
1626 		sc->result = reason;
1627 		goto fault;
1628 	}
1629 
1630 	if (session->state != ISCSI_STATE_LOGGED_IN) {
1631 		/*
1632 		 * to handle the race between when we set the recovery state
1633 		 * and block the session we requeue here (commands could
1634 		 * be entering our queuecommand while a block is starting
1635 		 * up because the block code is not locked)
1636 		 */
1637 		switch (session->state) {
1638 		case ISCSI_STATE_FAILED:
1639 		case ISCSI_STATE_IN_RECOVERY:
1640 			reason = FAILURE_SESSION_IN_RECOVERY;
1641 			sc->result = DID_IMM_RETRY << 16;
1642 			break;
1643 		case ISCSI_STATE_LOGGING_OUT:
1644 			reason = FAILURE_SESSION_LOGGING_OUT;
1645 			sc->result = DID_IMM_RETRY << 16;
1646 			break;
1647 		case ISCSI_STATE_RECOVERY_FAILED:
1648 			reason = FAILURE_SESSION_RECOVERY_TIMEOUT;
1649 			sc->result = DID_TRANSPORT_FAILFAST << 16;
1650 			break;
1651 		case ISCSI_STATE_TERMINATE:
1652 			reason = FAILURE_SESSION_TERMINATE;
1653 			sc->result = DID_NO_CONNECT << 16;
1654 			break;
1655 		default:
1656 			reason = FAILURE_SESSION_FREED;
1657 			sc->result = DID_NO_CONNECT << 16;
1658 		}
1659 		goto fault;
1660 	}
1661 
1662 	conn = session->leadconn;
1663 	if (!conn) {
1664 		reason = FAILURE_SESSION_FREED;
1665 		sc->result = DID_NO_CONNECT << 16;
1666 		goto fault;
1667 	}
1668 
1669 	if (test_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx)) {
1670 		reason = FAILURE_SESSION_IN_RECOVERY;
1671 		sc->result = DID_REQUEUE;
1672 		goto fault;
1673 	}
1674 
1675 	if (iscsi_check_cmdsn_window_closed(conn)) {
1676 		reason = FAILURE_WINDOW_CLOSED;
1677 		goto reject;
1678 	}
1679 
1680 	task = iscsi_alloc_task(conn, sc);
1681 	if (!task) {
1682 		reason = FAILURE_OOM;
1683 		goto reject;
1684 	}
1685 
1686 	if (!ihost->workq) {
1687 		reason = iscsi_prep_scsi_cmd_pdu(task);
1688 		if (reason) {
1689 			if (reason == -ENOMEM ||  reason == -EACCES) {
1690 				reason = FAILURE_OOM;
1691 				goto prepd_reject;
1692 			} else {
1693 				sc->result = DID_ABORT << 16;
1694 				goto prepd_fault;
1695 			}
1696 		}
1697 		if (session->tt->xmit_task(task)) {
1698 			session->cmdsn--;
1699 			reason = FAILURE_SESSION_NOT_READY;
1700 			goto prepd_reject;
1701 		}
1702 	} else {
1703 		list_add_tail(&task->running, &conn->cmdqueue);
1704 		iscsi_conn_queue_work(conn);
1705 	}
1706 
1707 	session->queued_cmdsn++;
1708 	spin_unlock(&session->lock);
1709 	spin_lock(host->host_lock);
1710 	return 0;
1711 
1712 prepd_reject:
1713 	sc->scsi_done = NULL;
1714 	iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
1715 reject:
1716 	spin_unlock(&session->lock);
1717 	ISCSI_DBG_SESSION(session, "cmd 0x%x rejected (%d)\n",
1718 			  sc->cmnd[0], reason);
1719 	spin_lock(host->host_lock);
1720 	return SCSI_MLQUEUE_TARGET_BUSY;
1721 
1722 prepd_fault:
1723 	sc->scsi_done = NULL;
1724 	iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
1725 fault:
1726 	spin_unlock(&session->lock);
1727 	ISCSI_DBG_SESSION(session, "iscsi: cmd 0x%x is not queued (%d)\n",
1728 			  sc->cmnd[0], reason);
1729 	if (!scsi_bidi_cmnd(sc))
1730 		scsi_set_resid(sc, scsi_bufflen(sc));
1731 	else {
1732 		scsi_out(sc)->resid = scsi_out(sc)->length;
1733 		scsi_in(sc)->resid = scsi_in(sc)->length;
1734 	}
1735 	done(sc);
1736 	spin_lock(host->host_lock);
1737 	return 0;
1738 }
1739 
1740 DEF_SCSI_QCMD(iscsi_queuecommand)
1741 EXPORT_SYMBOL_GPL(iscsi_queuecommand);
1742 
1743 int iscsi_change_queue_depth(struct scsi_device *sdev, int depth, int reason)
1744 {
1745 	switch (reason) {
1746 	case SCSI_QDEPTH_DEFAULT:
1747 		scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
1748 		break;
1749 	case SCSI_QDEPTH_QFULL:
1750 		scsi_track_queue_full(sdev, depth);
1751 		break;
1752 	case SCSI_QDEPTH_RAMP_UP:
1753 		scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
1754 		break;
1755 	default:
1756 		return -EOPNOTSUPP;
1757 	}
1758 	return sdev->queue_depth;
1759 }
1760 EXPORT_SYMBOL_GPL(iscsi_change_queue_depth);
1761 
1762 int iscsi_target_alloc(struct scsi_target *starget)
1763 {
1764 	struct iscsi_cls_session *cls_session = starget_to_session(starget);
1765 	struct iscsi_session *session = cls_session->dd_data;
1766 
1767 	starget->can_queue = session->scsi_cmds_max;
1768 	return 0;
1769 }
1770 EXPORT_SYMBOL_GPL(iscsi_target_alloc);
1771 
1772 static void iscsi_tmf_timedout(unsigned long data)
1773 {
1774 	struct iscsi_conn *conn = (struct iscsi_conn *)data;
1775 	struct iscsi_session *session = conn->session;
1776 
1777 	spin_lock(&session->lock);
1778 	if (conn->tmf_state == TMF_QUEUED) {
1779 		conn->tmf_state = TMF_TIMEDOUT;
1780 		ISCSI_DBG_EH(session, "tmf timedout\n");
1781 		/* unblock eh_abort() */
1782 		wake_up(&conn->ehwait);
1783 	}
1784 	spin_unlock(&session->lock);
1785 }
1786 
1787 static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
1788 				   struct iscsi_tm *hdr, int age,
1789 				   int timeout)
1790 {
1791 	struct iscsi_session *session = conn->session;
1792 	struct iscsi_task *task;
1793 
1794 	task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)hdr,
1795 				      NULL, 0);
1796 	if (!task) {
1797 		spin_unlock_bh(&session->lock);
1798 		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
1799 		spin_lock_bh(&session->lock);
1800 		ISCSI_DBG_EH(session, "tmf exec failure\n");
1801 		return -EPERM;
1802 	}
1803 	conn->tmfcmd_pdus_cnt++;
1804 	conn->tmf_timer.expires = timeout * HZ + jiffies;
1805 	conn->tmf_timer.function = iscsi_tmf_timedout;
1806 	conn->tmf_timer.data = (unsigned long)conn;
1807 	add_timer(&conn->tmf_timer);
1808 	ISCSI_DBG_EH(session, "tmf set timeout\n");
1809 
1810 	spin_unlock_bh(&session->lock);
1811 	mutex_unlock(&session->eh_mutex);
1812 
1813 	/*
1814 	 * block eh thread until:
1815 	 *
1816 	 * 1) tmf response
1817 	 * 2) tmf timeout
1818 	 * 3) session is terminated or restarted or userspace has
1819 	 * given up on recovery
1820 	 */
1821 	wait_event_interruptible(conn->ehwait, age != session->age ||
1822 				 session->state != ISCSI_STATE_LOGGED_IN ||
1823 				 conn->tmf_state != TMF_QUEUED);
1824 	if (signal_pending(current))
1825 		flush_signals(current);
1826 	del_timer_sync(&conn->tmf_timer);
1827 
1828 	mutex_lock(&session->eh_mutex);
1829 	spin_lock_bh(&session->lock);
1830 	/* if the session drops it will clean up the task */
1831 	if (age != session->age ||
1832 	    session->state != ISCSI_STATE_LOGGED_IN)
1833 		return -ENOTCONN;
1834 	return 0;
1835 }
1836 
1837 /*
1838  * Fail commands. session lock held and recv side suspended and xmit
1839  * thread flushed
1840  */
1841 static void fail_scsi_tasks(struct iscsi_conn *conn, unsigned lun,
1842 			    int error)
1843 {
1844 	struct iscsi_task *task;
1845 	int i;
1846 
1847 	for (i = 0; i < conn->session->cmds_max; i++) {
1848 		task = conn->session->cmds[i];
1849 		if (!task->sc || task->state == ISCSI_TASK_FREE)
1850 			continue;
1851 
1852 		if (lun != -1 && lun != task->sc->device->lun)
1853 			continue;
1854 
1855 		ISCSI_DBG_SESSION(conn->session,
1856 				  "failing sc %p itt 0x%x state %d\n",
1857 				  task->sc, task->itt, task->state);
1858 		fail_scsi_task(task, error);
1859 	}
1860 }
1861 
1862 /**
1863  * iscsi_suspend_queue - suspend iscsi_queuecommand
1864  * @conn: iscsi conn to stop queueing IO on
1865  *
1866  * This grabs the session lock to make sure no one is in
1867  * xmit_task/queuecommand, and then sets suspend to prevent
1868  * new commands from being queued. This only needs to be called
1869  * by offload drivers that need to sync a path like ep disconnect
1870  * with the iscsi_queuecommand/xmit_task. To start IO again libiscsi
1871  * will call iscsi_start_tx and iscsi_unblock_session when in FFP.
1872  */
1873 void iscsi_suspend_queue(struct iscsi_conn *conn)
1874 {
1875 	spin_lock_bh(&conn->session->lock);
1876 	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
1877 	spin_unlock_bh(&conn->session->lock);
1878 }
1879 EXPORT_SYMBOL_GPL(iscsi_suspend_queue);
1880 
1881 /**
1882  * iscsi_suspend_tx - suspend iscsi_data_xmit
1883  * @conn: iscsi conn tp stop processing IO on.
1884  *
1885  * This function sets the suspend bit to prevent iscsi_data_xmit
1886  * from sending new IO, and if work is queued on the xmit thread
1887  * it will wait for it to be completed.
1888  */
1889 void iscsi_suspend_tx(struct iscsi_conn *conn)
1890 {
1891 	struct Scsi_Host *shost = conn->session->host;
1892 	struct iscsi_host *ihost = shost_priv(shost);
1893 
1894 	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
1895 	if (ihost->workq)
1896 		flush_workqueue(ihost->workq);
1897 }
1898 EXPORT_SYMBOL_GPL(iscsi_suspend_tx);
1899 
1900 static void iscsi_start_tx(struct iscsi_conn *conn)
1901 {
1902 	clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
1903 	iscsi_conn_queue_work(conn);
1904 }
1905 
1906 /*
1907  * We want to make sure a ping is in flight. It has timed out.
1908  * And we are not busy processing a pdu that is making
1909  * progress but got started before the ping and is taking a while
1910  * to complete so the ping is just stuck behind it in a queue.
1911  */
1912 static int iscsi_has_ping_timed_out(struct iscsi_conn *conn)
1913 {
1914 	if (conn->ping_task &&
1915 	    time_before_eq(conn->last_recv + (conn->recv_timeout * HZ) +
1916 			   (conn->ping_timeout * HZ), jiffies))
1917 		return 1;
1918 	else
1919 		return 0;
1920 }
1921 
1922 static enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc)
1923 {
1924 	enum blk_eh_timer_return rc = BLK_EH_NOT_HANDLED;
1925 	struct iscsi_task *task = NULL, *running_task;
1926 	struct iscsi_cls_session *cls_session;
1927 	struct iscsi_session *session;
1928 	struct iscsi_conn *conn;
1929 	int i;
1930 
1931 	cls_session = starget_to_session(scsi_target(sc->device));
1932 	session = cls_session->dd_data;
1933 
1934 	ISCSI_DBG_EH(session, "scsi cmd %p timedout\n", sc);
1935 
1936 	spin_lock(&session->lock);
1937 	if (session->state != ISCSI_STATE_LOGGED_IN) {
1938 		/*
1939 		 * We are probably in the middle of iscsi recovery so let
1940 		 * that complete and handle the error.
1941 		 */
1942 		rc = BLK_EH_RESET_TIMER;
1943 		goto done;
1944 	}
1945 
1946 	conn = session->leadconn;
1947 	if (!conn) {
1948 		/* In the middle of shuting down */
1949 		rc = BLK_EH_RESET_TIMER;
1950 		goto done;
1951 	}
1952 
1953 	task = (struct iscsi_task *)sc->SCp.ptr;
1954 	if (!task) {
1955 		/*
1956 		 * Raced with completion. Just reset timer, and let it
1957 		 * complete normally
1958 		 */
1959 		rc = BLK_EH_RESET_TIMER;
1960 		goto done;
1961 	}
1962 
1963 	/*
1964 	 * If we have sent (at least queued to the network layer) a pdu or
1965 	 * recvd one for the task since the last timeout ask for
1966 	 * more time. If on the next timeout we have not made progress
1967 	 * we can check if it is the task or connection when we send the
1968 	 * nop as a ping.
1969 	 */
1970 	if (time_after(task->last_xfer, task->last_timeout)) {
1971 		ISCSI_DBG_EH(session, "Command making progress. Asking "
1972 			     "scsi-ml for more time to complete. "
1973 			     "Last data xfer at %lu. Last timeout was at "
1974 			     "%lu\n.", task->last_xfer, task->last_timeout);
1975 		task->have_checked_conn = false;
1976 		rc = BLK_EH_RESET_TIMER;
1977 		goto done;
1978 	}
1979 
1980 	if (!conn->recv_timeout && !conn->ping_timeout)
1981 		goto done;
1982 	/*
1983 	 * if the ping timedout then we are in the middle of cleaning up
1984 	 * and can let the iscsi eh handle it
1985 	 */
1986 	if (iscsi_has_ping_timed_out(conn)) {
1987 		rc = BLK_EH_RESET_TIMER;
1988 		goto done;
1989 	}
1990 
1991 	for (i = 0; i < conn->session->cmds_max; i++) {
1992 		running_task = conn->session->cmds[i];
1993 		if (!running_task->sc || running_task == task ||
1994 		     running_task->state != ISCSI_TASK_RUNNING)
1995 			continue;
1996 
1997 		/*
1998 		 * Only check if cmds started before this one have made
1999 		 * progress, or this could never fail
2000 		 */
2001 		if (time_after(running_task->sc->jiffies_at_alloc,
2002 			       task->sc->jiffies_at_alloc))
2003 			continue;
2004 
2005 		if (time_after(running_task->last_xfer, task->last_timeout)) {
2006 			/*
2007 			 * This task has not made progress, but a task
2008 			 * started before us has transferred data since
2009 			 * we started/last-checked. We could be queueing
2010 			 * too many tasks or the LU is bad.
2011 			 *
2012 			 * If the device is bad the cmds ahead of us on
2013 			 * other devs will complete, and this loop will
2014 			 * eventually fail starting the scsi eh.
2015 			 */
2016 			ISCSI_DBG_EH(session, "Command has not made progress "
2017 				     "but commands ahead of it have. "
2018 				     "Asking scsi-ml for more time to "
2019 				     "complete. Our last xfer vs running task "
2020 				     "last xfer %lu/%lu. Last check %lu.\n",
2021 				     task->last_xfer, running_task->last_xfer,
2022 				     task->last_timeout);
2023 			rc = BLK_EH_RESET_TIMER;
2024 			goto done;
2025 		}
2026 	}
2027 
2028 	/* Assumes nop timeout is shorter than scsi cmd timeout */
2029 	if (task->have_checked_conn)
2030 		goto done;
2031 
2032 	/*
2033 	 * Checking the transport already or nop from a cmd timeout still
2034 	 * running
2035 	 */
2036 	if (conn->ping_task) {
2037 		task->have_checked_conn = true;
2038 		rc = BLK_EH_RESET_TIMER;
2039 		goto done;
2040 	}
2041 
2042 	/* Make sure there is a transport check done */
2043 	iscsi_send_nopout(conn, NULL);
2044 	task->have_checked_conn = true;
2045 	rc = BLK_EH_RESET_TIMER;
2046 
2047 done:
2048 	if (task)
2049 		task->last_timeout = jiffies;
2050 	spin_unlock(&session->lock);
2051 	ISCSI_DBG_EH(session, "return %s\n", rc == BLK_EH_RESET_TIMER ?
2052 		     "timer reset" : "nh");
2053 	return rc;
2054 }
2055 
2056 static void iscsi_check_transport_timeouts(unsigned long data)
2057 {
2058 	struct iscsi_conn *conn = (struct iscsi_conn *)data;
2059 	struct iscsi_session *session = conn->session;
2060 	unsigned long recv_timeout, next_timeout = 0, last_recv;
2061 
2062 	spin_lock(&session->lock);
2063 	if (session->state != ISCSI_STATE_LOGGED_IN)
2064 		goto done;
2065 
2066 	recv_timeout = conn->recv_timeout;
2067 	if (!recv_timeout)
2068 		goto done;
2069 
2070 	recv_timeout *= HZ;
2071 	last_recv = conn->last_recv;
2072 
2073 	if (iscsi_has_ping_timed_out(conn)) {
2074 		iscsi_conn_printk(KERN_ERR, conn, "ping timeout of %d secs "
2075 				  "expired, recv timeout %d, last rx %lu, "
2076 				  "last ping %lu, now %lu\n",
2077 				  conn->ping_timeout, conn->recv_timeout,
2078 				  last_recv, conn->last_ping, jiffies);
2079 		spin_unlock(&session->lock);
2080 		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
2081 		return;
2082 	}
2083 
2084 	if (time_before_eq(last_recv + recv_timeout, jiffies)) {
2085 		/* send a ping to try to provoke some traffic */
2086 		ISCSI_DBG_CONN(conn, "Sending nopout as ping\n");
2087 		iscsi_send_nopout(conn, NULL);
2088 		next_timeout = conn->last_ping + (conn->ping_timeout * HZ);
2089 	} else
2090 		next_timeout = last_recv + recv_timeout;
2091 
2092 	ISCSI_DBG_CONN(conn, "Setting next tmo %lu\n", next_timeout);
2093 	mod_timer(&conn->transport_timer, next_timeout);
2094 done:
2095 	spin_unlock(&session->lock);
2096 }
2097 
2098 static void iscsi_prep_abort_task_pdu(struct iscsi_task *task,
2099 				      struct iscsi_tm *hdr)
2100 {
2101 	memset(hdr, 0, sizeof(*hdr));
2102 	hdr->opcode = ISCSI_OP_SCSI_TMFUNC | ISCSI_OP_IMMEDIATE;
2103 	hdr->flags = ISCSI_TM_FUNC_ABORT_TASK & ISCSI_FLAG_TM_FUNC_MASK;
2104 	hdr->flags |= ISCSI_FLAG_CMD_FINAL;
2105 	memcpy(hdr->lun, task->lun, sizeof(hdr->lun));
2106 	hdr->rtt = task->hdr_itt;
2107 	hdr->refcmdsn = task->cmdsn;
2108 }
2109 
2110 int iscsi_eh_abort(struct scsi_cmnd *sc)
2111 {
2112 	struct iscsi_cls_session *cls_session;
2113 	struct iscsi_session *session;
2114 	struct iscsi_conn *conn;
2115 	struct iscsi_task *task;
2116 	struct iscsi_tm *hdr;
2117 	int rc, age;
2118 
2119 	cls_session = starget_to_session(scsi_target(sc->device));
2120 	session = cls_session->dd_data;
2121 
2122 	ISCSI_DBG_EH(session, "aborting sc %p\n", sc);
2123 
2124 	mutex_lock(&session->eh_mutex);
2125 	spin_lock_bh(&session->lock);
2126 	/*
2127 	 * if session was ISCSI_STATE_IN_RECOVERY then we may not have
2128 	 * got the command.
2129 	 */
2130 	if (!sc->SCp.ptr) {
2131 		ISCSI_DBG_EH(session, "sc never reached iscsi layer or "
2132 				      "it completed.\n");
2133 		spin_unlock_bh(&session->lock);
2134 		mutex_unlock(&session->eh_mutex);
2135 		return SUCCESS;
2136 	}
2137 
2138 	/*
2139 	 * If we are not logged in or we have started a new session
2140 	 * then let the host reset code handle this
2141 	 */
2142 	if (!session->leadconn || session->state != ISCSI_STATE_LOGGED_IN ||
2143 	    sc->SCp.phase != session->age) {
2144 		spin_unlock_bh(&session->lock);
2145 		mutex_unlock(&session->eh_mutex);
2146 		ISCSI_DBG_EH(session, "failing abort due to dropped "
2147 				  "session.\n");
2148 		return FAILED;
2149 	}
2150 
2151 	conn = session->leadconn;
2152 	conn->eh_abort_cnt++;
2153 	age = session->age;
2154 
2155 	task = (struct iscsi_task *)sc->SCp.ptr;
2156 	ISCSI_DBG_EH(session, "aborting [sc %p itt 0x%x]\n",
2157 		     sc, task->itt);
2158 
2159 	/* task completed before time out */
2160 	if (!task->sc) {
2161 		ISCSI_DBG_EH(session, "sc completed while abort in progress\n");
2162 		goto success;
2163 	}
2164 
2165 	if (task->state == ISCSI_TASK_PENDING) {
2166 		fail_scsi_task(task, DID_ABORT);
2167 		goto success;
2168 	}
2169 
2170 	/* only have one tmf outstanding at a time */
2171 	if (conn->tmf_state != TMF_INITIAL)
2172 		goto failed;
2173 	conn->tmf_state = TMF_QUEUED;
2174 
2175 	hdr = &conn->tmhdr;
2176 	iscsi_prep_abort_task_pdu(task, hdr);
2177 
2178 	if (iscsi_exec_task_mgmt_fn(conn, hdr, age, session->abort_timeout)) {
2179 		rc = FAILED;
2180 		goto failed;
2181 	}
2182 
2183 	switch (conn->tmf_state) {
2184 	case TMF_SUCCESS:
2185 		spin_unlock_bh(&session->lock);
2186 		/*
2187 		 * stop tx side incase the target had sent a abort rsp but
2188 		 * the initiator was still writing out data.
2189 		 */
2190 		iscsi_suspend_tx(conn);
2191 		/*
2192 		 * we do not stop the recv side because targets have been
2193 		 * good and have never sent us a successful tmf response
2194 		 * then sent more data for the cmd.
2195 		 */
2196 		spin_lock_bh(&session->lock);
2197 		fail_scsi_task(task, DID_ABORT);
2198 		conn->tmf_state = TMF_INITIAL;
2199 		memset(hdr, 0, sizeof(*hdr));
2200 		spin_unlock_bh(&session->lock);
2201 		iscsi_start_tx(conn);
2202 		goto success_unlocked;
2203 	case TMF_TIMEDOUT:
2204 		spin_unlock_bh(&session->lock);
2205 		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
2206 		goto failed_unlocked;
2207 	case TMF_NOT_FOUND:
2208 		if (!sc->SCp.ptr) {
2209 			conn->tmf_state = TMF_INITIAL;
2210 			memset(hdr, 0, sizeof(*hdr));
2211 			/* task completed before tmf abort response */
2212 			ISCSI_DBG_EH(session, "sc completed while abort	in "
2213 					      "progress\n");
2214 			goto success;
2215 		}
2216 		/* fall through */
2217 	default:
2218 		conn->tmf_state = TMF_INITIAL;
2219 		goto failed;
2220 	}
2221 
2222 success:
2223 	spin_unlock_bh(&session->lock);
2224 success_unlocked:
2225 	ISCSI_DBG_EH(session, "abort success [sc %p itt 0x%x]\n",
2226 		     sc, task->itt);
2227 	mutex_unlock(&session->eh_mutex);
2228 	return SUCCESS;
2229 
2230 failed:
2231 	spin_unlock_bh(&session->lock);
2232 failed_unlocked:
2233 	ISCSI_DBG_EH(session, "abort failed [sc %p itt 0x%x]\n", sc,
2234 		     task ? task->itt : 0);
2235 	mutex_unlock(&session->eh_mutex);
2236 	return FAILED;
2237 }
2238 EXPORT_SYMBOL_GPL(iscsi_eh_abort);
2239 
2240 static void iscsi_prep_lun_reset_pdu(struct scsi_cmnd *sc, struct iscsi_tm *hdr)
2241 {
2242 	memset(hdr, 0, sizeof(*hdr));
2243 	hdr->opcode = ISCSI_OP_SCSI_TMFUNC | ISCSI_OP_IMMEDIATE;
2244 	hdr->flags = ISCSI_TM_FUNC_LOGICAL_UNIT_RESET & ISCSI_FLAG_TM_FUNC_MASK;
2245 	hdr->flags |= ISCSI_FLAG_CMD_FINAL;
2246 	int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
2247 	hdr->rtt = RESERVED_ITT;
2248 }
2249 
2250 int iscsi_eh_device_reset(struct scsi_cmnd *sc)
2251 {
2252 	struct iscsi_cls_session *cls_session;
2253 	struct iscsi_session *session;
2254 	struct iscsi_conn *conn;
2255 	struct iscsi_tm *hdr;
2256 	int rc = FAILED;
2257 
2258 	cls_session = starget_to_session(scsi_target(sc->device));
2259 	session = cls_session->dd_data;
2260 
2261 	ISCSI_DBG_EH(session, "LU Reset [sc %p lun %u]\n", sc, sc->device->lun);
2262 
2263 	mutex_lock(&session->eh_mutex);
2264 	spin_lock_bh(&session->lock);
2265 	/*
2266 	 * Just check if we are not logged in. We cannot check for
2267 	 * the phase because the reset could come from a ioctl.
2268 	 */
2269 	if (!session->leadconn || session->state != ISCSI_STATE_LOGGED_IN)
2270 		goto unlock;
2271 	conn = session->leadconn;
2272 
2273 	/* only have one tmf outstanding at a time */
2274 	if (conn->tmf_state != TMF_INITIAL)
2275 		goto unlock;
2276 	conn->tmf_state = TMF_QUEUED;
2277 
2278 	hdr = &conn->tmhdr;
2279 	iscsi_prep_lun_reset_pdu(sc, hdr);
2280 
2281 	if (iscsi_exec_task_mgmt_fn(conn, hdr, session->age,
2282 				    session->lu_reset_timeout)) {
2283 		rc = FAILED;
2284 		goto unlock;
2285 	}
2286 
2287 	switch (conn->tmf_state) {
2288 	case TMF_SUCCESS:
2289 		break;
2290 	case TMF_TIMEDOUT:
2291 		spin_unlock_bh(&session->lock);
2292 		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
2293 		goto done;
2294 	default:
2295 		conn->tmf_state = TMF_INITIAL;
2296 		goto unlock;
2297 	}
2298 
2299 	rc = SUCCESS;
2300 	spin_unlock_bh(&session->lock);
2301 
2302 	iscsi_suspend_tx(conn);
2303 
2304 	spin_lock_bh(&session->lock);
2305 	memset(hdr, 0, sizeof(*hdr));
2306 	fail_scsi_tasks(conn, sc->device->lun, DID_ERROR);
2307 	conn->tmf_state = TMF_INITIAL;
2308 	spin_unlock_bh(&session->lock);
2309 
2310 	iscsi_start_tx(conn);
2311 	goto done;
2312 
2313 unlock:
2314 	spin_unlock_bh(&session->lock);
2315 done:
2316 	ISCSI_DBG_EH(session, "dev reset result = %s\n",
2317 		     rc == SUCCESS ? "SUCCESS" : "FAILED");
2318 	mutex_unlock(&session->eh_mutex);
2319 	return rc;
2320 }
2321 EXPORT_SYMBOL_GPL(iscsi_eh_device_reset);
2322 
2323 void iscsi_session_recovery_timedout(struct iscsi_cls_session *cls_session)
2324 {
2325 	struct iscsi_session *session = cls_session->dd_data;
2326 
2327 	spin_lock_bh(&session->lock);
2328 	if (session->state != ISCSI_STATE_LOGGED_IN) {
2329 		session->state = ISCSI_STATE_RECOVERY_FAILED;
2330 		if (session->leadconn)
2331 			wake_up(&session->leadconn->ehwait);
2332 	}
2333 	spin_unlock_bh(&session->lock);
2334 }
2335 EXPORT_SYMBOL_GPL(iscsi_session_recovery_timedout);
2336 
2337 /**
2338  * iscsi_eh_session_reset - drop session and attempt relogin
2339  * @sc: scsi command
2340  *
2341  * This function will wait for a relogin, session termination from
2342  * userspace, or a recovery/replacement timeout.
2343  */
2344 int iscsi_eh_session_reset(struct scsi_cmnd *sc)
2345 {
2346 	struct iscsi_cls_session *cls_session;
2347 	struct iscsi_session *session;
2348 	struct iscsi_conn *conn;
2349 
2350 	cls_session = starget_to_session(scsi_target(sc->device));
2351 	session = cls_session->dd_data;
2352 	conn = session->leadconn;
2353 
2354 	mutex_lock(&session->eh_mutex);
2355 	spin_lock_bh(&session->lock);
2356 	if (session->state == ISCSI_STATE_TERMINATE) {
2357 failed:
2358 		ISCSI_DBG_EH(session,
2359 			     "failing session reset: Could not log back into "
2360 			     "%s, %s [age %d]\n", session->targetname,
2361 			     conn->persistent_address, session->age);
2362 		spin_unlock_bh(&session->lock);
2363 		mutex_unlock(&session->eh_mutex);
2364 		return FAILED;
2365 	}
2366 
2367 	spin_unlock_bh(&session->lock);
2368 	mutex_unlock(&session->eh_mutex);
2369 	/*
2370 	 * we drop the lock here but the leadconn cannot be destoyed while
2371 	 * we are in the scsi eh
2372 	 */
2373 	iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
2374 
2375 	ISCSI_DBG_EH(session, "wait for relogin\n");
2376 	wait_event_interruptible(conn->ehwait,
2377 				 session->state == ISCSI_STATE_TERMINATE ||
2378 				 session->state == ISCSI_STATE_LOGGED_IN ||
2379 				 session->state == ISCSI_STATE_RECOVERY_FAILED);
2380 	if (signal_pending(current))
2381 		flush_signals(current);
2382 
2383 	mutex_lock(&session->eh_mutex);
2384 	spin_lock_bh(&session->lock);
2385 	if (session->state == ISCSI_STATE_LOGGED_IN) {
2386 		ISCSI_DBG_EH(session,
2387 			     "session reset succeeded for %s,%s\n",
2388 			     session->targetname, conn->persistent_address);
2389 	} else
2390 		goto failed;
2391 	spin_unlock_bh(&session->lock);
2392 	mutex_unlock(&session->eh_mutex);
2393 	return SUCCESS;
2394 }
2395 EXPORT_SYMBOL_GPL(iscsi_eh_session_reset);
2396 
2397 static void iscsi_prep_tgt_reset_pdu(struct scsi_cmnd *sc, struct iscsi_tm *hdr)
2398 {
2399 	memset(hdr, 0, sizeof(*hdr));
2400 	hdr->opcode = ISCSI_OP_SCSI_TMFUNC | ISCSI_OP_IMMEDIATE;
2401 	hdr->flags = ISCSI_TM_FUNC_TARGET_WARM_RESET & ISCSI_FLAG_TM_FUNC_MASK;
2402 	hdr->flags |= ISCSI_FLAG_CMD_FINAL;
2403 	hdr->rtt = RESERVED_ITT;
2404 }
2405 
2406 /**
2407  * iscsi_eh_target_reset - reset target
2408  * @sc: scsi command
2409  *
2410  * This will attempt to send a warm target reset.
2411  */
2412 int iscsi_eh_target_reset(struct scsi_cmnd *sc)
2413 {
2414 	struct iscsi_cls_session *cls_session;
2415 	struct iscsi_session *session;
2416 	struct iscsi_conn *conn;
2417 	struct iscsi_tm *hdr;
2418 	int rc = FAILED;
2419 
2420 	cls_session = starget_to_session(scsi_target(sc->device));
2421 	session = cls_session->dd_data;
2422 
2423 	ISCSI_DBG_EH(session, "tgt Reset [sc %p tgt %s]\n", sc,
2424 		     session->targetname);
2425 
2426 	mutex_lock(&session->eh_mutex);
2427 	spin_lock_bh(&session->lock);
2428 	/*
2429 	 * Just check if we are not logged in. We cannot check for
2430 	 * the phase because the reset could come from a ioctl.
2431 	 */
2432 	if (!session->leadconn || session->state != ISCSI_STATE_LOGGED_IN)
2433 		goto unlock;
2434 	conn = session->leadconn;
2435 
2436 	/* only have one tmf outstanding at a time */
2437 	if (conn->tmf_state != TMF_INITIAL)
2438 		goto unlock;
2439 	conn->tmf_state = TMF_QUEUED;
2440 
2441 	hdr = &conn->tmhdr;
2442 	iscsi_prep_tgt_reset_pdu(sc, hdr);
2443 
2444 	if (iscsi_exec_task_mgmt_fn(conn, hdr, session->age,
2445 				    session->tgt_reset_timeout)) {
2446 		rc = FAILED;
2447 		goto unlock;
2448 	}
2449 
2450 	switch (conn->tmf_state) {
2451 	case TMF_SUCCESS:
2452 		break;
2453 	case TMF_TIMEDOUT:
2454 		spin_unlock_bh(&session->lock);
2455 		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
2456 		goto done;
2457 	default:
2458 		conn->tmf_state = TMF_INITIAL;
2459 		goto unlock;
2460 	}
2461 
2462 	rc = SUCCESS;
2463 	spin_unlock_bh(&session->lock);
2464 
2465 	iscsi_suspend_tx(conn);
2466 
2467 	spin_lock_bh(&session->lock);
2468 	memset(hdr, 0, sizeof(*hdr));
2469 	fail_scsi_tasks(conn, -1, DID_ERROR);
2470 	conn->tmf_state = TMF_INITIAL;
2471 	spin_unlock_bh(&session->lock);
2472 
2473 	iscsi_start_tx(conn);
2474 	goto done;
2475 
2476 unlock:
2477 	spin_unlock_bh(&session->lock);
2478 done:
2479 	ISCSI_DBG_EH(session, "tgt %s reset result = %s\n", session->targetname,
2480 		     rc == SUCCESS ? "SUCCESS" : "FAILED");
2481 	mutex_unlock(&session->eh_mutex);
2482 	return rc;
2483 }
2484 EXPORT_SYMBOL_GPL(iscsi_eh_target_reset);
2485 
2486 /**
2487  * iscsi_eh_recover_target - reset target and possibly the session
2488  * @sc: scsi command
2489  *
2490  * This will attempt to send a warm target reset. If that fails,
2491  * we will escalate to ERL0 session recovery.
2492  */
2493 int iscsi_eh_recover_target(struct scsi_cmnd *sc)
2494 {
2495 	int rc;
2496 
2497 	rc = iscsi_eh_target_reset(sc);
2498 	if (rc == FAILED)
2499 		rc = iscsi_eh_session_reset(sc);
2500 	return rc;
2501 }
2502 EXPORT_SYMBOL_GPL(iscsi_eh_recover_target);
2503 
2504 /*
2505  * Pre-allocate a pool of @max items of @item_size. By default, the pool
2506  * should be accessed via kfifo_{get,put} on q->queue.
2507  * Optionally, the caller can obtain the array of object pointers
2508  * by passing in a non-NULL @items pointer
2509  */
2510 int
2511 iscsi_pool_init(struct iscsi_pool *q, int max, void ***items, int item_size)
2512 {
2513 	int i, num_arrays = 1;
2514 
2515 	memset(q, 0, sizeof(*q));
2516 
2517 	q->max = max;
2518 
2519 	/* If the user passed an items pointer, he wants a copy of
2520 	 * the array. */
2521 	if (items)
2522 		num_arrays++;
2523 	q->pool = kzalloc(num_arrays * max * sizeof(void*), GFP_KERNEL);
2524 	if (q->pool == NULL)
2525 		return -ENOMEM;
2526 
2527 	kfifo_init(&q->queue, (void*)q->pool, max * sizeof(void*));
2528 
2529 	for (i = 0; i < max; i++) {
2530 		q->pool[i] = kzalloc(item_size, GFP_KERNEL);
2531 		if (q->pool[i] == NULL) {
2532 			q->max = i;
2533 			goto enomem;
2534 		}
2535 		kfifo_in(&q->queue, (void*)&q->pool[i], sizeof(void*));
2536 	}
2537 
2538 	if (items) {
2539 		*items = q->pool + max;
2540 		memcpy(*items, q->pool, max * sizeof(void *));
2541 	}
2542 
2543 	return 0;
2544 
2545 enomem:
2546 	iscsi_pool_free(q);
2547 	return -ENOMEM;
2548 }
2549 EXPORT_SYMBOL_GPL(iscsi_pool_init);
2550 
2551 void iscsi_pool_free(struct iscsi_pool *q)
2552 {
2553 	int i;
2554 
2555 	for (i = 0; i < q->max; i++)
2556 		kfree(q->pool[i]);
2557 	kfree(q->pool);
2558 }
2559 EXPORT_SYMBOL_GPL(iscsi_pool_free);
2560 
2561 /**
2562  * iscsi_host_add - add host to system
2563  * @shost: scsi host
2564  * @pdev: parent device
2565  *
2566  * This should be called by partial offload and software iscsi drivers
2567  * to add a host to the system.
2568  */
2569 int iscsi_host_add(struct Scsi_Host *shost, struct device *pdev)
2570 {
2571 	if (!shost->can_queue)
2572 		shost->can_queue = ISCSI_DEF_XMIT_CMDS_MAX;
2573 
2574 	if (!shost->cmd_per_lun)
2575 		shost->cmd_per_lun = ISCSI_DEF_CMD_PER_LUN;
2576 
2577 	if (!shost->transportt->eh_timed_out)
2578 		shost->transportt->eh_timed_out = iscsi_eh_cmd_timed_out;
2579 	return scsi_add_host(shost, pdev);
2580 }
2581 EXPORT_SYMBOL_GPL(iscsi_host_add);
2582 
2583 /**
2584  * iscsi_host_alloc - allocate a host and driver data
2585  * @sht: scsi host template
2586  * @dd_data_size: driver host data size
2587  * @xmit_can_sleep: bool indicating if LLD will queue IO from a work queue
2588  *
2589  * This should be called by partial offload and software iscsi drivers.
2590  * To access the driver specific memory use the iscsi_host_priv() macro.
2591  */
2592 struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,
2593 				   int dd_data_size, bool xmit_can_sleep)
2594 {
2595 	struct Scsi_Host *shost;
2596 	struct iscsi_host *ihost;
2597 
2598 	shost = scsi_host_alloc(sht, sizeof(struct iscsi_host) + dd_data_size);
2599 	if (!shost)
2600 		return NULL;
2601 	ihost = shost_priv(shost);
2602 
2603 	if (xmit_can_sleep) {
2604 		snprintf(ihost->workq_name, sizeof(ihost->workq_name),
2605 			"iscsi_q_%d", shost->host_no);
2606 		ihost->workq = create_singlethread_workqueue(ihost->workq_name);
2607 		if (!ihost->workq)
2608 			goto free_host;
2609 	}
2610 
2611 	spin_lock_init(&ihost->lock);
2612 	ihost->state = ISCSI_HOST_SETUP;
2613 	ihost->num_sessions = 0;
2614 	init_waitqueue_head(&ihost->session_removal_wq);
2615 	return shost;
2616 
2617 free_host:
2618 	scsi_host_put(shost);
2619 	return NULL;
2620 }
2621 EXPORT_SYMBOL_GPL(iscsi_host_alloc);
2622 
2623 static void iscsi_notify_host_removed(struct iscsi_cls_session *cls_session)
2624 {
2625 	iscsi_session_failure(cls_session->dd_data, ISCSI_ERR_INVALID_HOST);
2626 }
2627 
2628 /**
2629  * iscsi_host_remove - remove host and sessions
2630  * @shost: scsi host
2631  *
2632  * If there are any sessions left, this will initiate the removal and wait
2633  * for the completion.
2634  */
2635 void iscsi_host_remove(struct Scsi_Host *shost)
2636 {
2637 	struct iscsi_host *ihost = shost_priv(shost);
2638 	unsigned long flags;
2639 
2640 	spin_lock_irqsave(&ihost->lock, flags);
2641 	ihost->state = ISCSI_HOST_REMOVED;
2642 	spin_unlock_irqrestore(&ihost->lock, flags);
2643 
2644 	iscsi_host_for_each_session(shost, iscsi_notify_host_removed);
2645 	wait_event_interruptible(ihost->session_removal_wq,
2646 				 ihost->num_sessions == 0);
2647 	if (signal_pending(current))
2648 		flush_signals(current);
2649 
2650 	scsi_remove_host(shost);
2651 	if (ihost->workq)
2652 		destroy_workqueue(ihost->workq);
2653 }
2654 EXPORT_SYMBOL_GPL(iscsi_host_remove);
2655 
2656 void iscsi_host_free(struct Scsi_Host *shost)
2657 {
2658 	struct iscsi_host *ihost = shost_priv(shost);
2659 
2660 	kfree(ihost->netdev);
2661 	kfree(ihost->hwaddress);
2662 	kfree(ihost->initiatorname);
2663 	scsi_host_put(shost);
2664 }
2665 EXPORT_SYMBOL_GPL(iscsi_host_free);
2666 
2667 static void iscsi_host_dec_session_cnt(struct Scsi_Host *shost)
2668 {
2669 	struct iscsi_host *ihost = shost_priv(shost);
2670 	unsigned long flags;
2671 
2672 	shost = scsi_host_get(shost);
2673 	if (!shost) {
2674 		printk(KERN_ERR "Invalid state. Cannot notify host removal "
2675 		      "of session teardown event because host already "
2676 		      "removed.\n");
2677 		return;
2678 	}
2679 
2680 	spin_lock_irqsave(&ihost->lock, flags);
2681 	ihost->num_sessions--;
2682 	if (ihost->num_sessions == 0)
2683 		wake_up(&ihost->session_removal_wq);
2684 	spin_unlock_irqrestore(&ihost->lock, flags);
2685 	scsi_host_put(shost);
2686 }
2687 
2688 /**
2689  * iscsi_session_setup - create iscsi cls session and host and session
2690  * @iscsit: iscsi transport template
2691  * @shost: scsi host
2692  * @cmds_max: session can queue
2693  * @cmd_task_size: LLD task private data size
2694  * @initial_cmdsn: initial CmdSN
2695  *
2696  * This can be used by software iscsi_transports that allocate
2697  * a session per scsi host.
2698  *
2699  * Callers should set cmds_max to the largest total numer (mgmt + scsi) of
2700  * tasks they support. The iscsi layer reserves ISCSI_MGMT_CMDS_MAX tasks
2701  * for nop handling and login/logout requests.
2702  */
2703 struct iscsi_cls_session *
2704 iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
2705 		    uint16_t cmds_max, int dd_size, int cmd_task_size,
2706 		    uint32_t initial_cmdsn, unsigned int id)
2707 {
2708 	struct iscsi_host *ihost = shost_priv(shost);
2709 	struct iscsi_session *session;
2710 	struct iscsi_cls_session *cls_session;
2711 	int cmd_i, scsi_cmds, total_cmds = cmds_max;
2712 	unsigned long flags;
2713 
2714 	spin_lock_irqsave(&ihost->lock, flags);
2715 	if (ihost->state == ISCSI_HOST_REMOVED) {
2716 		spin_unlock_irqrestore(&ihost->lock, flags);
2717 		return NULL;
2718 	}
2719 	ihost->num_sessions++;
2720 	spin_unlock_irqrestore(&ihost->lock, flags);
2721 
2722 	if (!total_cmds)
2723 		total_cmds = ISCSI_DEF_XMIT_CMDS_MAX;
2724 	/*
2725 	 * The iscsi layer needs some tasks for nop handling and tmfs,
2726 	 * so the cmds_max must at least be greater than ISCSI_MGMT_CMDS_MAX
2727 	 * + 1 command for scsi IO.
2728 	 */
2729 	if (total_cmds < ISCSI_TOTAL_CMDS_MIN) {
2730 		printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
2731 		       "must be a power of two that is at least %d.\n",
2732 		       total_cmds, ISCSI_TOTAL_CMDS_MIN);
2733 		goto dec_session_count;
2734 	}
2735 
2736 	if (total_cmds > ISCSI_TOTAL_CMDS_MAX) {
2737 		printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
2738 		       "must be a power of 2 less than or equal to %d.\n",
2739 		       cmds_max, ISCSI_TOTAL_CMDS_MAX);
2740 		total_cmds = ISCSI_TOTAL_CMDS_MAX;
2741 	}
2742 
2743 	if (!is_power_of_2(total_cmds)) {
2744 		printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
2745 		       "must be a power of 2.\n", total_cmds);
2746 		total_cmds = rounddown_pow_of_two(total_cmds);
2747 		if (total_cmds < ISCSI_TOTAL_CMDS_MIN)
2748 			return NULL;
2749 		printk(KERN_INFO "iscsi: Rounding can_queue to %d.\n",
2750 		       total_cmds);
2751 	}
2752 	scsi_cmds = total_cmds - ISCSI_MGMT_CMDS_MAX;
2753 
2754 	cls_session = iscsi_alloc_session(shost, iscsit,
2755 					  sizeof(struct iscsi_session) +
2756 					  dd_size);
2757 	if (!cls_session)
2758 		goto dec_session_count;
2759 	session = cls_session->dd_data;
2760 	session->cls_session = cls_session;
2761 	session->host = shost;
2762 	session->state = ISCSI_STATE_FREE;
2763 	session->fast_abort = 1;
2764 	session->tgt_reset_timeout = 30;
2765 	session->lu_reset_timeout = 15;
2766 	session->abort_timeout = 10;
2767 	session->scsi_cmds_max = scsi_cmds;
2768 	session->cmds_max = total_cmds;
2769 	session->queued_cmdsn = session->cmdsn = initial_cmdsn;
2770 	session->exp_cmdsn = initial_cmdsn + 1;
2771 	session->max_cmdsn = initial_cmdsn + 1;
2772 	session->max_r2t = 1;
2773 	session->tt = iscsit;
2774 	session->dd_data = cls_session->dd_data + sizeof(*session);
2775 	mutex_init(&session->eh_mutex);
2776 	spin_lock_init(&session->lock);
2777 
2778 	/* initialize SCSI PDU commands pool */
2779 	if (iscsi_pool_init(&session->cmdpool, session->cmds_max,
2780 			    (void***)&session->cmds,
2781 			    cmd_task_size + sizeof(struct iscsi_task)))
2782 		goto cmdpool_alloc_fail;
2783 
2784 	/* pre-format cmds pool with ITT */
2785 	for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
2786 		struct iscsi_task *task = session->cmds[cmd_i];
2787 
2788 		if (cmd_task_size)
2789 			task->dd_data = &task[1];
2790 		task->itt = cmd_i;
2791 		task->state = ISCSI_TASK_FREE;
2792 		INIT_LIST_HEAD(&task->running);
2793 	}
2794 
2795 	if (!try_module_get(iscsit->owner))
2796 		goto module_get_fail;
2797 
2798 	if (iscsi_add_session(cls_session, id))
2799 		goto cls_session_fail;
2800 
2801 	return cls_session;
2802 
2803 cls_session_fail:
2804 	module_put(iscsit->owner);
2805 module_get_fail:
2806 	iscsi_pool_free(&session->cmdpool);
2807 cmdpool_alloc_fail:
2808 	iscsi_free_session(cls_session);
2809 dec_session_count:
2810 	iscsi_host_dec_session_cnt(shost);
2811 	return NULL;
2812 }
2813 EXPORT_SYMBOL_GPL(iscsi_session_setup);
2814 
2815 /**
2816  * iscsi_session_teardown - destroy session, host, and cls_session
2817  * @cls_session: iscsi session
2818  *
2819  * The driver must have called iscsi_remove_session before
2820  * calling this.
2821  */
2822 void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
2823 {
2824 	struct iscsi_session *session = cls_session->dd_data;
2825 	struct module *owner = cls_session->transport->owner;
2826 	struct Scsi_Host *shost = session->host;
2827 
2828 	iscsi_pool_free(&session->cmdpool);
2829 
2830 	kfree(session->password);
2831 	kfree(session->password_in);
2832 	kfree(session->username);
2833 	kfree(session->username_in);
2834 	kfree(session->targetname);
2835 	kfree(session->initiatorname);
2836 	kfree(session->ifacename);
2837 
2838 	iscsi_destroy_session(cls_session);
2839 	iscsi_host_dec_session_cnt(shost);
2840 	module_put(owner);
2841 }
2842 EXPORT_SYMBOL_GPL(iscsi_session_teardown);
2843 
2844 /**
2845  * iscsi_conn_setup - create iscsi_cls_conn and iscsi_conn
2846  * @cls_session: iscsi_cls_session
2847  * @dd_size: private driver data size
2848  * @conn_idx: cid
2849  */
2850 struct iscsi_cls_conn *
2851 iscsi_conn_setup(struct iscsi_cls_session *cls_session, int dd_size,
2852 		 uint32_t conn_idx)
2853 {
2854 	struct iscsi_session *session = cls_session->dd_data;
2855 	struct iscsi_conn *conn;
2856 	struct iscsi_cls_conn *cls_conn;
2857 	char *data;
2858 
2859 	cls_conn = iscsi_create_conn(cls_session, sizeof(*conn) + dd_size,
2860 				     conn_idx);
2861 	if (!cls_conn)
2862 		return NULL;
2863 	conn = cls_conn->dd_data;
2864 	memset(conn, 0, sizeof(*conn) + dd_size);
2865 
2866 	conn->dd_data = cls_conn->dd_data + sizeof(*conn);
2867 	conn->session = session;
2868 	conn->cls_conn = cls_conn;
2869 	conn->c_stage = ISCSI_CONN_INITIAL_STAGE;
2870 	conn->id = conn_idx;
2871 	conn->exp_statsn = 0;
2872 	conn->tmf_state = TMF_INITIAL;
2873 
2874 	init_timer(&conn->transport_timer);
2875 	conn->transport_timer.data = (unsigned long)conn;
2876 	conn->transport_timer.function = iscsi_check_transport_timeouts;
2877 
2878 	INIT_LIST_HEAD(&conn->mgmtqueue);
2879 	INIT_LIST_HEAD(&conn->cmdqueue);
2880 	INIT_LIST_HEAD(&conn->requeue);
2881 	INIT_WORK(&conn->xmitwork, iscsi_xmitworker);
2882 
2883 	/* allocate login_task used for the login/text sequences */
2884 	spin_lock_bh(&session->lock);
2885 	if (!kfifo_out(&session->cmdpool.queue,
2886                          (void*)&conn->login_task,
2887 			 sizeof(void*))) {
2888 		spin_unlock_bh(&session->lock);
2889 		goto login_task_alloc_fail;
2890 	}
2891 	spin_unlock_bh(&session->lock);
2892 
2893 	data = (char *) __get_free_pages(GFP_KERNEL,
2894 					 get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
2895 	if (!data)
2896 		goto login_task_data_alloc_fail;
2897 	conn->login_task->data = conn->data = data;
2898 
2899 	init_timer(&conn->tmf_timer);
2900 	init_waitqueue_head(&conn->ehwait);
2901 
2902 	return cls_conn;
2903 
2904 login_task_data_alloc_fail:
2905 	kfifo_in(&session->cmdpool.queue, (void*)&conn->login_task,
2906 		    sizeof(void*));
2907 login_task_alloc_fail:
2908 	iscsi_destroy_conn(cls_conn);
2909 	return NULL;
2910 }
2911 EXPORT_SYMBOL_GPL(iscsi_conn_setup);
2912 
2913 /**
2914  * iscsi_conn_teardown - teardown iscsi connection
2915  * cls_conn: iscsi class connection
2916  *
2917  * TODO: we may need to make this into a two step process
2918  * like scsi-mls remove + put host
2919  */
2920 void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
2921 {
2922 	struct iscsi_conn *conn = cls_conn->dd_data;
2923 	struct iscsi_session *session = conn->session;
2924 	unsigned long flags;
2925 
2926 	del_timer_sync(&conn->transport_timer);
2927 
2928 	spin_lock_bh(&session->lock);
2929 	conn->c_stage = ISCSI_CONN_CLEANUP_WAIT;
2930 	if (session->leadconn == conn) {
2931 		/*
2932 		 * leading connection? then give up on recovery.
2933 		 */
2934 		session->state = ISCSI_STATE_TERMINATE;
2935 		wake_up(&conn->ehwait);
2936 	}
2937 	spin_unlock_bh(&session->lock);
2938 
2939 	/*
2940 	 * Block until all in-progress commands for this connection
2941 	 * time out or fail.
2942 	 */
2943 	for (;;) {
2944 		spin_lock_irqsave(session->host->host_lock, flags);
2945 		if (!session->host->host_busy) { /* OK for ERL == 0 */
2946 			spin_unlock_irqrestore(session->host->host_lock, flags);
2947 			break;
2948 		}
2949 		spin_unlock_irqrestore(session->host->host_lock, flags);
2950 		msleep_interruptible(500);
2951 		iscsi_conn_printk(KERN_INFO, conn, "iscsi conn_destroy(): "
2952 				  "host_busy %d host_failed %d\n",
2953 				  session->host->host_busy,
2954 				  session->host->host_failed);
2955 		/*
2956 		 * force eh_abort() to unblock
2957 		 */
2958 		wake_up(&conn->ehwait);
2959 	}
2960 
2961 	/* flush queued up work because we free the connection below */
2962 	iscsi_suspend_tx(conn);
2963 
2964 	spin_lock_bh(&session->lock);
2965 	free_pages((unsigned long) conn->data,
2966 		   get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
2967 	kfree(conn->persistent_address);
2968 	kfifo_in(&session->cmdpool.queue, (void*)&conn->login_task,
2969 		    sizeof(void*));
2970 	if (session->leadconn == conn)
2971 		session->leadconn = NULL;
2972 	spin_unlock_bh(&session->lock);
2973 
2974 	iscsi_destroy_conn(cls_conn);
2975 }
2976 EXPORT_SYMBOL_GPL(iscsi_conn_teardown);
2977 
2978 int iscsi_conn_start(struct iscsi_cls_conn *cls_conn)
2979 {
2980 	struct iscsi_conn *conn = cls_conn->dd_data;
2981 	struct iscsi_session *session = conn->session;
2982 
2983 	if (!session) {
2984 		iscsi_conn_printk(KERN_ERR, conn,
2985 				  "can't start unbound connection\n");
2986 		return -EPERM;
2987 	}
2988 
2989 	if ((session->imm_data_en || !session->initial_r2t_en) &&
2990 	     session->first_burst > session->max_burst) {
2991 		iscsi_conn_printk(KERN_INFO, conn, "invalid burst lengths: "
2992 				  "first_burst %d max_burst %d\n",
2993 				  session->first_burst, session->max_burst);
2994 		return -EINVAL;
2995 	}
2996 
2997 	if (conn->ping_timeout && !conn->recv_timeout) {
2998 		iscsi_conn_printk(KERN_ERR, conn, "invalid recv timeout of "
2999 				  "zero. Using 5 seconds\n.");
3000 		conn->recv_timeout = 5;
3001 	}
3002 
3003 	if (conn->recv_timeout && !conn->ping_timeout) {
3004 		iscsi_conn_printk(KERN_ERR, conn, "invalid ping timeout of "
3005 				  "zero. Using 5 seconds.\n");
3006 		conn->ping_timeout = 5;
3007 	}
3008 
3009 	spin_lock_bh(&session->lock);
3010 	conn->c_stage = ISCSI_CONN_STARTED;
3011 	session->state = ISCSI_STATE_LOGGED_IN;
3012 	session->queued_cmdsn = session->cmdsn;
3013 
3014 	conn->last_recv = jiffies;
3015 	conn->last_ping = jiffies;
3016 	if (conn->recv_timeout && conn->ping_timeout)
3017 		mod_timer(&conn->transport_timer,
3018 			  jiffies + (conn->recv_timeout * HZ));
3019 
3020 	switch(conn->stop_stage) {
3021 	case STOP_CONN_RECOVER:
3022 		/*
3023 		 * unblock eh_abort() if it is blocked. re-try all
3024 		 * commands after successful recovery
3025 		 */
3026 		conn->stop_stage = 0;
3027 		conn->tmf_state = TMF_INITIAL;
3028 		session->age++;
3029 		if (session->age == 16)
3030 			session->age = 0;
3031 		break;
3032 	case STOP_CONN_TERM:
3033 		conn->stop_stage = 0;
3034 		break;
3035 	default:
3036 		break;
3037 	}
3038 	spin_unlock_bh(&session->lock);
3039 
3040 	iscsi_unblock_session(session->cls_session);
3041 	wake_up(&conn->ehwait);
3042 	return 0;
3043 }
3044 EXPORT_SYMBOL_GPL(iscsi_conn_start);
3045 
3046 static void
3047 fail_mgmt_tasks(struct iscsi_session *session, struct iscsi_conn *conn)
3048 {
3049 	struct iscsi_task *task;
3050 	int i, state;
3051 
3052 	for (i = 0; i < conn->session->cmds_max; i++) {
3053 		task = conn->session->cmds[i];
3054 		if (task->sc)
3055 			continue;
3056 
3057 		if (task->state == ISCSI_TASK_FREE)
3058 			continue;
3059 
3060 		ISCSI_DBG_SESSION(conn->session,
3061 				  "failing mgmt itt 0x%x state %d\n",
3062 				  task->itt, task->state);
3063 		state = ISCSI_TASK_ABRT_SESS_RECOV;
3064 		if (task->state == ISCSI_TASK_PENDING)
3065 			state = ISCSI_TASK_COMPLETED;
3066 		iscsi_complete_task(task, state);
3067 
3068 	}
3069 }
3070 
3071 static void iscsi_start_session_recovery(struct iscsi_session *session,
3072 					 struct iscsi_conn *conn, int flag)
3073 {
3074 	int old_stop_stage;
3075 
3076 	mutex_lock(&session->eh_mutex);
3077 	spin_lock_bh(&session->lock);
3078 	if (conn->stop_stage == STOP_CONN_TERM) {
3079 		spin_unlock_bh(&session->lock);
3080 		mutex_unlock(&session->eh_mutex);
3081 		return;
3082 	}
3083 
3084 	/*
3085 	 * When this is called for the in_login state, we only want to clean
3086 	 * up the login task and connection. We do not need to block and set
3087 	 * the recovery state again
3088 	 */
3089 	if (flag == STOP_CONN_TERM)
3090 		session->state = ISCSI_STATE_TERMINATE;
3091 	else if (conn->stop_stage != STOP_CONN_RECOVER)
3092 		session->state = ISCSI_STATE_IN_RECOVERY;
3093 
3094 	old_stop_stage = conn->stop_stage;
3095 	conn->stop_stage = flag;
3096 	spin_unlock_bh(&session->lock);
3097 
3098 	del_timer_sync(&conn->transport_timer);
3099 	iscsi_suspend_tx(conn);
3100 
3101 	spin_lock_bh(&session->lock);
3102 	conn->c_stage = ISCSI_CONN_STOPPED;
3103 	spin_unlock_bh(&session->lock);
3104 
3105 	/*
3106 	 * for connection level recovery we should not calculate
3107 	 * header digest. conn->hdr_size used for optimization
3108 	 * in hdr_extract() and will be re-negotiated at
3109 	 * set_param() time.
3110 	 */
3111 	if (flag == STOP_CONN_RECOVER) {
3112 		conn->hdrdgst_en = 0;
3113 		conn->datadgst_en = 0;
3114 		if (session->state == ISCSI_STATE_IN_RECOVERY &&
3115 		    old_stop_stage != STOP_CONN_RECOVER) {
3116 			ISCSI_DBG_SESSION(session, "blocking session\n");
3117 			iscsi_block_session(session->cls_session);
3118 		}
3119 	}
3120 
3121 	/*
3122 	 * flush queues.
3123 	 */
3124 	spin_lock_bh(&session->lock);
3125 	fail_scsi_tasks(conn, -1, DID_TRANSPORT_DISRUPTED);
3126 	fail_mgmt_tasks(session, conn);
3127 	memset(&conn->tmhdr, 0, sizeof(conn->tmhdr));
3128 	spin_unlock_bh(&session->lock);
3129 	mutex_unlock(&session->eh_mutex);
3130 }
3131 
3132 void iscsi_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
3133 {
3134 	struct iscsi_conn *conn = cls_conn->dd_data;
3135 	struct iscsi_session *session = conn->session;
3136 
3137 	switch (flag) {
3138 	case STOP_CONN_RECOVER:
3139 	case STOP_CONN_TERM:
3140 		iscsi_start_session_recovery(session, conn, flag);
3141 		break;
3142 	default:
3143 		iscsi_conn_printk(KERN_ERR, conn,
3144 				  "invalid stop flag %d\n", flag);
3145 	}
3146 }
3147 EXPORT_SYMBOL_GPL(iscsi_conn_stop);
3148 
3149 int iscsi_conn_bind(struct iscsi_cls_session *cls_session,
3150 		    struct iscsi_cls_conn *cls_conn, int is_leading)
3151 {
3152 	struct iscsi_session *session = cls_session->dd_data;
3153 	struct iscsi_conn *conn = cls_conn->dd_data;
3154 
3155 	spin_lock_bh(&session->lock);
3156 	if (is_leading)
3157 		session->leadconn = conn;
3158 	spin_unlock_bh(&session->lock);
3159 
3160 	/*
3161 	 * Unblock xmitworker(), Login Phase will pass through.
3162 	 */
3163 	clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
3164 	clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
3165 	return 0;
3166 }
3167 EXPORT_SYMBOL_GPL(iscsi_conn_bind);
3168 
3169 static int iscsi_switch_str_param(char **param, char *new_val_buf)
3170 {
3171 	char *new_val;
3172 
3173 	if (*param) {
3174 		if (!strcmp(*param, new_val_buf))
3175 			return 0;
3176 	}
3177 
3178 	new_val = kstrdup(new_val_buf, GFP_NOIO);
3179 	if (!new_val)
3180 		return -ENOMEM;
3181 
3182 	kfree(*param);
3183 	*param = new_val;
3184 	return 0;
3185 }
3186 
3187 int iscsi_set_param(struct iscsi_cls_conn *cls_conn,
3188 		    enum iscsi_param param, char *buf, int buflen)
3189 {
3190 	struct iscsi_conn *conn = cls_conn->dd_data;
3191 	struct iscsi_session *session = conn->session;
3192 	uint32_t value;
3193 
3194 	switch(param) {
3195 	case ISCSI_PARAM_FAST_ABORT:
3196 		sscanf(buf, "%d", &session->fast_abort);
3197 		break;
3198 	case ISCSI_PARAM_ABORT_TMO:
3199 		sscanf(buf, "%d", &session->abort_timeout);
3200 		break;
3201 	case ISCSI_PARAM_LU_RESET_TMO:
3202 		sscanf(buf, "%d", &session->lu_reset_timeout);
3203 		break;
3204 	case ISCSI_PARAM_TGT_RESET_TMO:
3205 		sscanf(buf, "%d", &session->tgt_reset_timeout);
3206 		break;
3207 	case ISCSI_PARAM_PING_TMO:
3208 		sscanf(buf, "%d", &conn->ping_timeout);
3209 		break;
3210 	case ISCSI_PARAM_RECV_TMO:
3211 		sscanf(buf, "%d", &conn->recv_timeout);
3212 		break;
3213 	case ISCSI_PARAM_MAX_RECV_DLENGTH:
3214 		sscanf(buf, "%d", &conn->max_recv_dlength);
3215 		break;
3216 	case ISCSI_PARAM_MAX_XMIT_DLENGTH:
3217 		sscanf(buf, "%d", &conn->max_xmit_dlength);
3218 		break;
3219 	case ISCSI_PARAM_HDRDGST_EN:
3220 		sscanf(buf, "%d", &conn->hdrdgst_en);
3221 		break;
3222 	case ISCSI_PARAM_DATADGST_EN:
3223 		sscanf(buf, "%d", &conn->datadgst_en);
3224 		break;
3225 	case ISCSI_PARAM_INITIAL_R2T_EN:
3226 		sscanf(buf, "%d", &session->initial_r2t_en);
3227 		break;
3228 	case ISCSI_PARAM_MAX_R2T:
3229 		sscanf(buf, "%d", &session->max_r2t);
3230 		break;
3231 	case ISCSI_PARAM_IMM_DATA_EN:
3232 		sscanf(buf, "%d", &session->imm_data_en);
3233 		break;
3234 	case ISCSI_PARAM_FIRST_BURST:
3235 		sscanf(buf, "%d", &session->first_burst);
3236 		break;
3237 	case ISCSI_PARAM_MAX_BURST:
3238 		sscanf(buf, "%d", &session->max_burst);
3239 		break;
3240 	case ISCSI_PARAM_PDU_INORDER_EN:
3241 		sscanf(buf, "%d", &session->pdu_inorder_en);
3242 		break;
3243 	case ISCSI_PARAM_DATASEQ_INORDER_EN:
3244 		sscanf(buf, "%d", &session->dataseq_inorder_en);
3245 		break;
3246 	case ISCSI_PARAM_ERL:
3247 		sscanf(buf, "%d", &session->erl);
3248 		break;
3249 	case ISCSI_PARAM_IFMARKER_EN:
3250 		sscanf(buf, "%d", &value);
3251 		BUG_ON(value);
3252 		break;
3253 	case ISCSI_PARAM_OFMARKER_EN:
3254 		sscanf(buf, "%d", &value);
3255 		BUG_ON(value);
3256 		break;
3257 	case ISCSI_PARAM_EXP_STATSN:
3258 		sscanf(buf, "%u", &conn->exp_statsn);
3259 		break;
3260 	case ISCSI_PARAM_USERNAME:
3261 		return iscsi_switch_str_param(&session->username, buf);
3262 	case ISCSI_PARAM_USERNAME_IN:
3263 		return iscsi_switch_str_param(&session->username_in, buf);
3264 	case ISCSI_PARAM_PASSWORD:
3265 		return iscsi_switch_str_param(&session->password, buf);
3266 	case ISCSI_PARAM_PASSWORD_IN:
3267 		return iscsi_switch_str_param(&session->password_in, buf);
3268 	case ISCSI_PARAM_TARGET_NAME:
3269 		return iscsi_switch_str_param(&session->targetname, buf);
3270 	case ISCSI_PARAM_TPGT:
3271 		sscanf(buf, "%d", &session->tpgt);
3272 		break;
3273 	case ISCSI_PARAM_PERSISTENT_PORT:
3274 		sscanf(buf, "%d", &conn->persistent_port);
3275 		break;
3276 	case ISCSI_PARAM_PERSISTENT_ADDRESS:
3277 		return iscsi_switch_str_param(&conn->persistent_address, buf);
3278 	case ISCSI_PARAM_IFACE_NAME:
3279 		return iscsi_switch_str_param(&session->ifacename, buf);
3280 	case ISCSI_PARAM_INITIATOR_NAME:
3281 		return iscsi_switch_str_param(&session->initiatorname, buf);
3282 	default:
3283 		return -ENOSYS;
3284 	}
3285 
3286 	return 0;
3287 }
3288 EXPORT_SYMBOL_GPL(iscsi_set_param);
3289 
3290 int iscsi_session_get_param(struct iscsi_cls_session *cls_session,
3291 			    enum iscsi_param param, char *buf)
3292 {
3293 	struct iscsi_session *session = cls_session->dd_data;
3294 	int len;
3295 
3296 	switch(param) {
3297 	case ISCSI_PARAM_FAST_ABORT:
3298 		len = sprintf(buf, "%d\n", session->fast_abort);
3299 		break;
3300 	case ISCSI_PARAM_ABORT_TMO:
3301 		len = sprintf(buf, "%d\n", session->abort_timeout);
3302 		break;
3303 	case ISCSI_PARAM_LU_RESET_TMO:
3304 		len = sprintf(buf, "%d\n", session->lu_reset_timeout);
3305 		break;
3306 	case ISCSI_PARAM_TGT_RESET_TMO:
3307 		len = sprintf(buf, "%d\n", session->tgt_reset_timeout);
3308 		break;
3309 	case ISCSI_PARAM_INITIAL_R2T_EN:
3310 		len = sprintf(buf, "%d\n", session->initial_r2t_en);
3311 		break;
3312 	case ISCSI_PARAM_MAX_R2T:
3313 		len = sprintf(buf, "%hu\n", session->max_r2t);
3314 		break;
3315 	case ISCSI_PARAM_IMM_DATA_EN:
3316 		len = sprintf(buf, "%d\n", session->imm_data_en);
3317 		break;
3318 	case ISCSI_PARAM_FIRST_BURST:
3319 		len = sprintf(buf, "%u\n", session->first_burst);
3320 		break;
3321 	case ISCSI_PARAM_MAX_BURST:
3322 		len = sprintf(buf, "%u\n", session->max_burst);
3323 		break;
3324 	case ISCSI_PARAM_PDU_INORDER_EN:
3325 		len = sprintf(buf, "%d\n", session->pdu_inorder_en);
3326 		break;
3327 	case ISCSI_PARAM_DATASEQ_INORDER_EN:
3328 		len = sprintf(buf, "%d\n", session->dataseq_inorder_en);
3329 		break;
3330 	case ISCSI_PARAM_ERL:
3331 		len = sprintf(buf, "%d\n", session->erl);
3332 		break;
3333 	case ISCSI_PARAM_TARGET_NAME:
3334 		len = sprintf(buf, "%s\n", session->targetname);
3335 		break;
3336 	case ISCSI_PARAM_TPGT:
3337 		len = sprintf(buf, "%d\n", session->tpgt);
3338 		break;
3339 	case ISCSI_PARAM_USERNAME:
3340 		len = sprintf(buf, "%s\n", session->username);
3341 		break;
3342 	case ISCSI_PARAM_USERNAME_IN:
3343 		len = sprintf(buf, "%s\n", session->username_in);
3344 		break;
3345 	case ISCSI_PARAM_PASSWORD:
3346 		len = sprintf(buf, "%s\n", session->password);
3347 		break;
3348 	case ISCSI_PARAM_PASSWORD_IN:
3349 		len = sprintf(buf, "%s\n", session->password_in);
3350 		break;
3351 	case ISCSI_PARAM_IFACE_NAME:
3352 		len = sprintf(buf, "%s\n", session->ifacename);
3353 		break;
3354 	case ISCSI_PARAM_INITIATOR_NAME:
3355 		len = sprintf(buf, "%s\n", session->initiatorname);
3356 		break;
3357 	default:
3358 		return -ENOSYS;
3359 	}
3360 
3361 	return len;
3362 }
3363 EXPORT_SYMBOL_GPL(iscsi_session_get_param);
3364 
3365 int iscsi_conn_get_param(struct iscsi_cls_conn *cls_conn,
3366 			 enum iscsi_param param, char *buf)
3367 {
3368 	struct iscsi_conn *conn = cls_conn->dd_data;
3369 	int len;
3370 
3371 	switch(param) {
3372 	case ISCSI_PARAM_PING_TMO:
3373 		len = sprintf(buf, "%u\n", conn->ping_timeout);
3374 		break;
3375 	case ISCSI_PARAM_RECV_TMO:
3376 		len = sprintf(buf, "%u\n", conn->recv_timeout);
3377 		break;
3378 	case ISCSI_PARAM_MAX_RECV_DLENGTH:
3379 		len = sprintf(buf, "%u\n", conn->max_recv_dlength);
3380 		break;
3381 	case ISCSI_PARAM_MAX_XMIT_DLENGTH:
3382 		len = sprintf(buf, "%u\n", conn->max_xmit_dlength);
3383 		break;
3384 	case ISCSI_PARAM_HDRDGST_EN:
3385 		len = sprintf(buf, "%d\n", conn->hdrdgst_en);
3386 		break;
3387 	case ISCSI_PARAM_DATADGST_EN:
3388 		len = sprintf(buf, "%d\n", conn->datadgst_en);
3389 		break;
3390 	case ISCSI_PARAM_IFMARKER_EN:
3391 		len = sprintf(buf, "%d\n", conn->ifmarker_en);
3392 		break;
3393 	case ISCSI_PARAM_OFMARKER_EN:
3394 		len = sprintf(buf, "%d\n", conn->ofmarker_en);
3395 		break;
3396 	case ISCSI_PARAM_EXP_STATSN:
3397 		len = sprintf(buf, "%u\n", conn->exp_statsn);
3398 		break;
3399 	case ISCSI_PARAM_PERSISTENT_PORT:
3400 		len = sprintf(buf, "%d\n", conn->persistent_port);
3401 		break;
3402 	case ISCSI_PARAM_PERSISTENT_ADDRESS:
3403 		len = sprintf(buf, "%s\n", conn->persistent_address);
3404 		break;
3405 	default:
3406 		return -ENOSYS;
3407 	}
3408 
3409 	return len;
3410 }
3411 EXPORT_SYMBOL_GPL(iscsi_conn_get_param);
3412 
3413 int iscsi_host_get_param(struct Scsi_Host *shost, enum iscsi_host_param param,
3414 			 char *buf)
3415 {
3416 	struct iscsi_host *ihost = shost_priv(shost);
3417 	int len;
3418 
3419 	switch (param) {
3420 	case ISCSI_HOST_PARAM_NETDEV_NAME:
3421 		len = sprintf(buf, "%s\n", ihost->netdev);
3422 		break;
3423 	case ISCSI_HOST_PARAM_HWADDRESS:
3424 		len = sprintf(buf, "%s\n", ihost->hwaddress);
3425 		break;
3426 	case ISCSI_HOST_PARAM_INITIATOR_NAME:
3427 		len = sprintf(buf, "%s\n", ihost->initiatorname);
3428 		break;
3429 	case ISCSI_HOST_PARAM_IPADDRESS:
3430 		len = sprintf(buf, "%s\n", ihost->local_address);
3431 		break;
3432 	default:
3433 		return -ENOSYS;
3434 	}
3435 
3436 	return len;
3437 }
3438 EXPORT_SYMBOL_GPL(iscsi_host_get_param);
3439 
3440 int iscsi_host_set_param(struct Scsi_Host *shost, enum iscsi_host_param param,
3441 			 char *buf, int buflen)
3442 {
3443 	struct iscsi_host *ihost = shost_priv(shost);
3444 
3445 	switch (param) {
3446 	case ISCSI_HOST_PARAM_NETDEV_NAME:
3447 		return iscsi_switch_str_param(&ihost->netdev, buf);
3448 	case ISCSI_HOST_PARAM_HWADDRESS:
3449 		return iscsi_switch_str_param(&ihost->hwaddress, buf);
3450 	case ISCSI_HOST_PARAM_INITIATOR_NAME:
3451 		return iscsi_switch_str_param(&ihost->initiatorname, buf);
3452 	default:
3453 		return -ENOSYS;
3454 	}
3455 
3456 	return 0;
3457 }
3458 EXPORT_SYMBOL_GPL(iscsi_host_set_param);
3459 
3460 MODULE_AUTHOR("Mike Christie");
3461 MODULE_DESCRIPTION("iSCSI library functions");
3462 MODULE_LICENSE("GPL");
3463