1 /*******************************************************************************
2  * This file contains the iSCSI Target specific utility functions.
3  *
4  * (c) Copyright 2007-2013 Datera, Inc.
5  *
6  * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  ******************************************************************************/
18 
19 #include <linux/list.h>
20 #include <linux/percpu_ida.h>
21 #include <scsi/scsi_tcq.h>
22 #include <scsi/iscsi_proto.h>
23 #include <target/target_core_base.h>
24 #include <target/target_core_fabric.h>
25 #include <target/target_core_configfs.h>
26 #include <target/iscsi/iscsi_transport.h>
27 
28 #include "iscsi_target_core.h"
29 #include "iscsi_target_parameters.h"
30 #include "iscsi_target_seq_pdu_list.h"
31 #include "iscsi_target_datain_values.h"
32 #include "iscsi_target_erl0.h"
33 #include "iscsi_target_erl1.h"
34 #include "iscsi_target_erl2.h"
35 #include "iscsi_target_tpg.h"
36 #include "iscsi_target_tq.h"
37 #include "iscsi_target_util.h"
38 #include "iscsi_target.h"
39 
40 #define PRINT_BUFF(buff, len)					\
41 {								\
42 	int zzz;						\
43 								\
44 	pr_debug("%d:\n", __LINE__);				\
45 	for (zzz = 0; zzz < len; zzz++) {			\
46 		if (zzz % 16 == 0) {				\
47 			if (zzz)				\
48 				pr_debug("\n");			\
49 			pr_debug("%4i: ", zzz);			\
50 		}						\
51 		pr_debug("%02x ", (unsigned char) (buff)[zzz]);	\
52 	}							\
53 	if ((len + 1) % 16)					\
54 		pr_debug("\n");					\
55 }
56 
57 extern struct list_head g_tiqn_list;
58 extern spinlock_t tiqn_lock;
59 
60 /*
61  *	Called with cmd->r2t_lock held.
62  */
63 int iscsit_add_r2t_to_list(
64 	struct iscsi_cmd *cmd,
65 	u32 offset,
66 	u32 xfer_len,
67 	int recovery,
68 	u32 r2t_sn)
69 {
70 	struct iscsi_r2t *r2t;
71 
72 	r2t = kmem_cache_zalloc(lio_r2t_cache, GFP_ATOMIC);
73 	if (!r2t) {
74 		pr_err("Unable to allocate memory for struct iscsi_r2t.\n");
75 		return -1;
76 	}
77 	INIT_LIST_HEAD(&r2t->r2t_list);
78 
79 	r2t->recovery_r2t = recovery;
80 	r2t->r2t_sn = (!r2t_sn) ? cmd->r2t_sn++ : r2t_sn;
81 	r2t->offset = offset;
82 	r2t->xfer_len = xfer_len;
83 	list_add_tail(&r2t->r2t_list, &cmd->cmd_r2t_list);
84 	spin_unlock_bh(&cmd->r2t_lock);
85 
86 	iscsit_add_cmd_to_immediate_queue(cmd, cmd->conn, ISTATE_SEND_R2T);
87 
88 	spin_lock_bh(&cmd->r2t_lock);
89 	return 0;
90 }
91 
92 struct iscsi_r2t *iscsit_get_r2t_for_eos(
93 	struct iscsi_cmd *cmd,
94 	u32 offset,
95 	u32 length)
96 {
97 	struct iscsi_r2t *r2t;
98 
99 	spin_lock_bh(&cmd->r2t_lock);
100 	list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
101 		if ((r2t->offset <= offset) &&
102 		    (r2t->offset + r2t->xfer_len) >= (offset + length)) {
103 			spin_unlock_bh(&cmd->r2t_lock);
104 			return r2t;
105 		}
106 	}
107 	spin_unlock_bh(&cmd->r2t_lock);
108 
109 	pr_err("Unable to locate R2T for Offset: %u, Length:"
110 			" %u\n", offset, length);
111 	return NULL;
112 }
113 
114 struct iscsi_r2t *iscsit_get_r2t_from_list(struct iscsi_cmd *cmd)
115 {
116 	struct iscsi_r2t *r2t;
117 
118 	spin_lock_bh(&cmd->r2t_lock);
119 	list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
120 		if (!r2t->sent_r2t) {
121 			spin_unlock_bh(&cmd->r2t_lock);
122 			return r2t;
123 		}
124 	}
125 	spin_unlock_bh(&cmd->r2t_lock);
126 
127 	pr_err("Unable to locate next R2T to send for ITT:"
128 			" 0x%08x.\n", cmd->init_task_tag);
129 	return NULL;
130 }
131 
132 /*
133  *	Called with cmd->r2t_lock held.
134  */
135 void iscsit_free_r2t(struct iscsi_r2t *r2t, struct iscsi_cmd *cmd)
136 {
137 	list_del(&r2t->r2t_list);
138 	kmem_cache_free(lio_r2t_cache, r2t);
139 }
140 
141 void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd)
142 {
143 	struct iscsi_r2t *r2t, *r2t_tmp;
144 
145 	spin_lock_bh(&cmd->r2t_lock);
146 	list_for_each_entry_safe(r2t, r2t_tmp, &cmd->cmd_r2t_list, r2t_list)
147 		iscsit_free_r2t(r2t, cmd);
148 	spin_unlock_bh(&cmd->r2t_lock);
149 }
150 
151 /*
152  * May be called from software interrupt (timer) context for allocating
153  * iSCSI NopINs.
154  */
155 struct iscsi_cmd *iscsit_allocate_cmd(struct iscsi_conn *conn, int state)
156 {
157 	struct iscsi_cmd *cmd;
158 	struct se_session *se_sess = conn->sess->se_sess;
159 	int size, tag;
160 
161 	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, state);
162 	if (tag < 0)
163 		return NULL;
164 
165 	size = sizeof(struct iscsi_cmd) + conn->conn_transport->priv_size;
166 	cmd = (struct iscsi_cmd *)(se_sess->sess_cmd_map + (tag * size));
167 	memset(cmd, 0, size);
168 
169 	cmd->se_cmd.map_tag = tag;
170 	cmd->conn = conn;
171 	INIT_LIST_HEAD(&cmd->i_conn_node);
172 	INIT_LIST_HEAD(&cmd->datain_list);
173 	INIT_LIST_HEAD(&cmd->cmd_r2t_list);
174 	spin_lock_init(&cmd->datain_lock);
175 	spin_lock_init(&cmd->dataout_timeout_lock);
176 	spin_lock_init(&cmd->istate_lock);
177 	spin_lock_init(&cmd->error_lock);
178 	spin_lock_init(&cmd->r2t_lock);
179 
180 	return cmd;
181 }
182 EXPORT_SYMBOL(iscsit_allocate_cmd);
183 
184 struct iscsi_seq *iscsit_get_seq_holder_for_datain(
185 	struct iscsi_cmd *cmd,
186 	u32 seq_send_order)
187 {
188 	u32 i;
189 
190 	for (i = 0; i < cmd->seq_count; i++)
191 		if (cmd->seq_list[i].seq_send_order == seq_send_order)
192 			return &cmd->seq_list[i];
193 
194 	return NULL;
195 }
196 
197 struct iscsi_seq *iscsit_get_seq_holder_for_r2t(struct iscsi_cmd *cmd)
198 {
199 	u32 i;
200 
201 	if (!cmd->seq_list) {
202 		pr_err("struct iscsi_cmd->seq_list is NULL!\n");
203 		return NULL;
204 	}
205 
206 	for (i = 0; i < cmd->seq_count; i++) {
207 		if (cmd->seq_list[i].type != SEQTYPE_NORMAL)
208 			continue;
209 		if (cmd->seq_list[i].seq_send_order == cmd->seq_send_order) {
210 			cmd->seq_send_order++;
211 			return &cmd->seq_list[i];
212 		}
213 	}
214 
215 	return NULL;
216 }
217 
218 struct iscsi_r2t *iscsit_get_holder_for_r2tsn(
219 	struct iscsi_cmd *cmd,
220 	u32 r2t_sn)
221 {
222 	struct iscsi_r2t *r2t;
223 
224 	spin_lock_bh(&cmd->r2t_lock);
225 	list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
226 		if (r2t->r2t_sn == r2t_sn) {
227 			spin_unlock_bh(&cmd->r2t_lock);
228 			return r2t;
229 		}
230 	}
231 	spin_unlock_bh(&cmd->r2t_lock);
232 
233 	return NULL;
234 }
235 
236 static inline int iscsit_check_received_cmdsn(struct iscsi_session *sess, u32 cmdsn)
237 {
238 	int ret;
239 
240 	/*
241 	 * This is the proper method of checking received CmdSN against
242 	 * ExpCmdSN and MaxCmdSN values, as well as accounting for out
243 	 * or order CmdSNs due to multiple connection sessions and/or
244 	 * CRC failures.
245 	 */
246 	if (iscsi_sna_gt(cmdsn, sess->max_cmd_sn)) {
247 		pr_err("Received CmdSN: 0x%08x is greater than"
248 		       " MaxCmdSN: 0x%08x, ignoring.\n", cmdsn,
249 		       sess->max_cmd_sn);
250 		ret = CMDSN_MAXCMDSN_OVERRUN;
251 
252 	} else if (cmdsn == sess->exp_cmd_sn) {
253 		sess->exp_cmd_sn++;
254 		pr_debug("Received CmdSN matches ExpCmdSN,"
255 		      " incremented ExpCmdSN to: 0x%08x\n",
256 		      sess->exp_cmd_sn);
257 		ret = CMDSN_NORMAL_OPERATION;
258 
259 	} else if (iscsi_sna_gt(cmdsn, sess->exp_cmd_sn)) {
260 		pr_debug("Received CmdSN: 0x%08x is greater"
261 		      " than ExpCmdSN: 0x%08x, not acknowledging.\n",
262 		      cmdsn, sess->exp_cmd_sn);
263 		ret = CMDSN_HIGHER_THAN_EXP;
264 
265 	} else {
266 		pr_err("Received CmdSN: 0x%08x is less than"
267 		       " ExpCmdSN: 0x%08x, ignoring.\n", cmdsn,
268 		       sess->exp_cmd_sn);
269 		ret = CMDSN_LOWER_THAN_EXP;
270 	}
271 
272 	return ret;
273 }
274 
275 /*
276  * Commands may be received out of order if MC/S is in use.
277  * Ensure they are executed in CmdSN order.
278  */
279 int iscsit_sequence_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
280 			unsigned char *buf, __be32 cmdsn)
281 {
282 	int ret, cmdsn_ret;
283 	bool reject = false;
284 	u8 reason = ISCSI_REASON_BOOKMARK_NO_RESOURCES;
285 
286 	mutex_lock(&conn->sess->cmdsn_mutex);
287 
288 	cmdsn_ret = iscsit_check_received_cmdsn(conn->sess, be32_to_cpu(cmdsn));
289 	switch (cmdsn_ret) {
290 	case CMDSN_NORMAL_OPERATION:
291 		ret = iscsit_execute_cmd(cmd, 0);
292 		if ((ret >= 0) && !list_empty(&conn->sess->sess_ooo_cmdsn_list))
293 			iscsit_execute_ooo_cmdsns(conn->sess);
294 		else if (ret < 0) {
295 			reject = true;
296 			ret = CMDSN_ERROR_CANNOT_RECOVER;
297 		}
298 		break;
299 	case CMDSN_HIGHER_THAN_EXP:
300 		ret = iscsit_handle_ooo_cmdsn(conn->sess, cmd, be32_to_cpu(cmdsn));
301 		if (ret < 0) {
302 			reject = true;
303 			ret = CMDSN_ERROR_CANNOT_RECOVER;
304 			break;
305 		}
306 		ret = CMDSN_HIGHER_THAN_EXP;
307 		break;
308 	case CMDSN_LOWER_THAN_EXP:
309 	case CMDSN_MAXCMDSN_OVERRUN:
310 	default:
311 		cmd->i_state = ISTATE_REMOVE;
312 		iscsit_add_cmd_to_immediate_queue(cmd, conn, cmd->i_state);
313 		/*
314 		 * Existing callers for iscsit_sequence_cmd() will silently
315 		 * ignore commands with CMDSN_LOWER_THAN_EXP, so force this
316 		 * return for CMDSN_MAXCMDSN_OVERRUN as well..
317 		 */
318 		ret = CMDSN_LOWER_THAN_EXP;
319 		break;
320 	}
321 	mutex_unlock(&conn->sess->cmdsn_mutex);
322 
323 	if (reject)
324 		iscsit_reject_cmd(cmd, reason, buf);
325 
326 	return ret;
327 }
328 EXPORT_SYMBOL(iscsit_sequence_cmd);
329 
330 int iscsit_check_unsolicited_dataout(struct iscsi_cmd *cmd, unsigned char *buf)
331 {
332 	struct iscsi_conn *conn = cmd->conn;
333 	struct se_cmd *se_cmd = &cmd->se_cmd;
334 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
335 	u32 payload_length = ntoh24(hdr->dlength);
336 
337 	if (conn->sess->sess_ops->InitialR2T) {
338 		pr_err("Received unexpected unsolicited data"
339 			" while InitialR2T=Yes, protocol error.\n");
340 		transport_send_check_condition_and_sense(se_cmd,
341 				TCM_UNEXPECTED_UNSOLICITED_DATA, 0);
342 		return -1;
343 	}
344 
345 	if ((cmd->first_burst_len + payload_length) >
346 	     conn->sess->sess_ops->FirstBurstLength) {
347 		pr_err("Total %u bytes exceeds FirstBurstLength: %u"
348 			" for this Unsolicited DataOut Burst.\n",
349 			(cmd->first_burst_len + payload_length),
350 				conn->sess->sess_ops->FirstBurstLength);
351 		transport_send_check_condition_and_sense(se_cmd,
352 				TCM_INCORRECT_AMOUNT_OF_DATA, 0);
353 		return -1;
354 	}
355 
356 	if (!(hdr->flags & ISCSI_FLAG_CMD_FINAL))
357 		return 0;
358 
359 	if (((cmd->first_burst_len + payload_length) != cmd->se_cmd.data_length) &&
360 	    ((cmd->first_burst_len + payload_length) !=
361 	      conn->sess->sess_ops->FirstBurstLength)) {
362 		pr_err("Unsolicited non-immediate data received %u"
363 			" does not equal FirstBurstLength: %u, and does"
364 			" not equal ExpXferLen %u.\n",
365 			(cmd->first_burst_len + payload_length),
366 			conn->sess->sess_ops->FirstBurstLength, cmd->se_cmd.data_length);
367 		transport_send_check_condition_and_sense(se_cmd,
368 				TCM_INCORRECT_AMOUNT_OF_DATA, 0);
369 		return -1;
370 	}
371 	return 0;
372 }
373 
374 struct iscsi_cmd *iscsit_find_cmd_from_itt(
375 	struct iscsi_conn *conn,
376 	itt_t init_task_tag)
377 {
378 	struct iscsi_cmd *cmd;
379 
380 	spin_lock_bh(&conn->cmd_lock);
381 	list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
382 		if (cmd->init_task_tag == init_task_tag) {
383 			spin_unlock_bh(&conn->cmd_lock);
384 			return cmd;
385 		}
386 	}
387 	spin_unlock_bh(&conn->cmd_lock);
388 
389 	pr_err("Unable to locate ITT: 0x%08x on CID: %hu",
390 			init_task_tag, conn->cid);
391 	return NULL;
392 }
393 
394 struct iscsi_cmd *iscsit_find_cmd_from_itt_or_dump(
395 	struct iscsi_conn *conn,
396 	itt_t init_task_tag,
397 	u32 length)
398 {
399 	struct iscsi_cmd *cmd;
400 
401 	spin_lock_bh(&conn->cmd_lock);
402 	list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
403 		if (cmd->cmd_flags & ICF_GOT_LAST_DATAOUT)
404 			continue;
405 		if (cmd->init_task_tag == init_task_tag) {
406 			spin_unlock_bh(&conn->cmd_lock);
407 			return cmd;
408 		}
409 	}
410 	spin_unlock_bh(&conn->cmd_lock);
411 
412 	pr_err("Unable to locate ITT: 0x%08x on CID: %hu,"
413 			" dumping payload\n", init_task_tag, conn->cid);
414 	if (length)
415 		iscsit_dump_data_payload(conn, length, 1);
416 
417 	return NULL;
418 }
419 
420 struct iscsi_cmd *iscsit_find_cmd_from_ttt(
421 	struct iscsi_conn *conn,
422 	u32 targ_xfer_tag)
423 {
424 	struct iscsi_cmd *cmd = NULL;
425 
426 	spin_lock_bh(&conn->cmd_lock);
427 	list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
428 		if (cmd->targ_xfer_tag == targ_xfer_tag) {
429 			spin_unlock_bh(&conn->cmd_lock);
430 			return cmd;
431 		}
432 	}
433 	spin_unlock_bh(&conn->cmd_lock);
434 
435 	pr_err("Unable to locate TTT: 0x%08x on CID: %hu\n",
436 			targ_xfer_tag, conn->cid);
437 	return NULL;
438 }
439 
440 int iscsit_find_cmd_for_recovery(
441 	struct iscsi_session *sess,
442 	struct iscsi_cmd **cmd_ptr,
443 	struct iscsi_conn_recovery **cr_ptr,
444 	itt_t init_task_tag)
445 {
446 	struct iscsi_cmd *cmd = NULL;
447 	struct iscsi_conn_recovery *cr;
448 	/*
449 	 * Scan through the inactive connection recovery list's command list.
450 	 * If init_task_tag matches the command is still alligent.
451 	 */
452 	spin_lock(&sess->cr_i_lock);
453 	list_for_each_entry(cr, &sess->cr_inactive_list, cr_list) {
454 		spin_lock(&cr->conn_recovery_cmd_lock);
455 		list_for_each_entry(cmd, &cr->conn_recovery_cmd_list, i_conn_node) {
456 			if (cmd->init_task_tag == init_task_tag) {
457 				spin_unlock(&cr->conn_recovery_cmd_lock);
458 				spin_unlock(&sess->cr_i_lock);
459 
460 				*cr_ptr = cr;
461 				*cmd_ptr = cmd;
462 				return -2;
463 			}
464 		}
465 		spin_unlock(&cr->conn_recovery_cmd_lock);
466 	}
467 	spin_unlock(&sess->cr_i_lock);
468 	/*
469 	 * Scan through the active connection recovery list's command list.
470 	 * If init_task_tag matches the command is ready to be reassigned.
471 	 */
472 	spin_lock(&sess->cr_a_lock);
473 	list_for_each_entry(cr, &sess->cr_active_list, cr_list) {
474 		spin_lock(&cr->conn_recovery_cmd_lock);
475 		list_for_each_entry(cmd, &cr->conn_recovery_cmd_list, i_conn_node) {
476 			if (cmd->init_task_tag == init_task_tag) {
477 				spin_unlock(&cr->conn_recovery_cmd_lock);
478 				spin_unlock(&sess->cr_a_lock);
479 
480 				*cr_ptr = cr;
481 				*cmd_ptr = cmd;
482 				return 0;
483 			}
484 		}
485 		spin_unlock(&cr->conn_recovery_cmd_lock);
486 	}
487 	spin_unlock(&sess->cr_a_lock);
488 
489 	return -1;
490 }
491 
492 void iscsit_add_cmd_to_immediate_queue(
493 	struct iscsi_cmd *cmd,
494 	struct iscsi_conn *conn,
495 	u8 state)
496 {
497 	struct iscsi_queue_req *qr;
498 
499 	qr = kmem_cache_zalloc(lio_qr_cache, GFP_ATOMIC);
500 	if (!qr) {
501 		pr_err("Unable to allocate memory for"
502 				" struct iscsi_queue_req\n");
503 		return;
504 	}
505 	INIT_LIST_HEAD(&qr->qr_list);
506 	qr->cmd = cmd;
507 	qr->state = state;
508 
509 	spin_lock_bh(&conn->immed_queue_lock);
510 	list_add_tail(&qr->qr_list, &conn->immed_queue_list);
511 	atomic_inc(&cmd->immed_queue_count);
512 	atomic_set(&conn->check_immediate_queue, 1);
513 	spin_unlock_bh(&conn->immed_queue_lock);
514 
515 	wake_up(&conn->queues_wq);
516 }
517 
518 struct iscsi_queue_req *iscsit_get_cmd_from_immediate_queue(struct iscsi_conn *conn)
519 {
520 	struct iscsi_queue_req *qr;
521 
522 	spin_lock_bh(&conn->immed_queue_lock);
523 	if (list_empty(&conn->immed_queue_list)) {
524 		spin_unlock_bh(&conn->immed_queue_lock);
525 		return NULL;
526 	}
527 	qr = list_first_entry(&conn->immed_queue_list,
528 			      struct iscsi_queue_req, qr_list);
529 
530 	list_del(&qr->qr_list);
531 	if (qr->cmd)
532 		atomic_dec(&qr->cmd->immed_queue_count);
533 	spin_unlock_bh(&conn->immed_queue_lock);
534 
535 	return qr;
536 }
537 
538 static void iscsit_remove_cmd_from_immediate_queue(
539 	struct iscsi_cmd *cmd,
540 	struct iscsi_conn *conn)
541 {
542 	struct iscsi_queue_req *qr, *qr_tmp;
543 
544 	spin_lock_bh(&conn->immed_queue_lock);
545 	if (!atomic_read(&cmd->immed_queue_count)) {
546 		spin_unlock_bh(&conn->immed_queue_lock);
547 		return;
548 	}
549 
550 	list_for_each_entry_safe(qr, qr_tmp, &conn->immed_queue_list, qr_list) {
551 		if (qr->cmd != cmd)
552 			continue;
553 
554 		atomic_dec(&qr->cmd->immed_queue_count);
555 		list_del(&qr->qr_list);
556 		kmem_cache_free(lio_qr_cache, qr);
557 	}
558 	spin_unlock_bh(&conn->immed_queue_lock);
559 
560 	if (atomic_read(&cmd->immed_queue_count)) {
561 		pr_err("ITT: 0x%08x immed_queue_count: %d\n",
562 			cmd->init_task_tag,
563 			atomic_read(&cmd->immed_queue_count));
564 	}
565 }
566 
567 void iscsit_add_cmd_to_response_queue(
568 	struct iscsi_cmd *cmd,
569 	struct iscsi_conn *conn,
570 	u8 state)
571 {
572 	struct iscsi_queue_req *qr;
573 
574 	qr = kmem_cache_zalloc(lio_qr_cache, GFP_ATOMIC);
575 	if (!qr) {
576 		pr_err("Unable to allocate memory for"
577 			" struct iscsi_queue_req\n");
578 		return;
579 	}
580 	INIT_LIST_HEAD(&qr->qr_list);
581 	qr->cmd = cmd;
582 	qr->state = state;
583 
584 	spin_lock_bh(&conn->response_queue_lock);
585 	list_add_tail(&qr->qr_list, &conn->response_queue_list);
586 	atomic_inc(&cmd->response_queue_count);
587 	spin_unlock_bh(&conn->response_queue_lock);
588 
589 	wake_up(&conn->queues_wq);
590 }
591 
592 struct iscsi_queue_req *iscsit_get_cmd_from_response_queue(struct iscsi_conn *conn)
593 {
594 	struct iscsi_queue_req *qr;
595 
596 	spin_lock_bh(&conn->response_queue_lock);
597 	if (list_empty(&conn->response_queue_list)) {
598 		spin_unlock_bh(&conn->response_queue_lock);
599 		return NULL;
600 	}
601 
602 	qr = list_first_entry(&conn->response_queue_list,
603 			      struct iscsi_queue_req, qr_list);
604 
605 	list_del(&qr->qr_list);
606 	if (qr->cmd)
607 		atomic_dec(&qr->cmd->response_queue_count);
608 	spin_unlock_bh(&conn->response_queue_lock);
609 
610 	return qr;
611 }
612 
613 static void iscsit_remove_cmd_from_response_queue(
614 	struct iscsi_cmd *cmd,
615 	struct iscsi_conn *conn)
616 {
617 	struct iscsi_queue_req *qr, *qr_tmp;
618 
619 	spin_lock_bh(&conn->response_queue_lock);
620 	if (!atomic_read(&cmd->response_queue_count)) {
621 		spin_unlock_bh(&conn->response_queue_lock);
622 		return;
623 	}
624 
625 	list_for_each_entry_safe(qr, qr_tmp, &conn->response_queue_list,
626 				qr_list) {
627 		if (qr->cmd != cmd)
628 			continue;
629 
630 		atomic_dec(&qr->cmd->response_queue_count);
631 		list_del(&qr->qr_list);
632 		kmem_cache_free(lio_qr_cache, qr);
633 	}
634 	spin_unlock_bh(&conn->response_queue_lock);
635 
636 	if (atomic_read(&cmd->response_queue_count)) {
637 		pr_err("ITT: 0x%08x response_queue_count: %d\n",
638 			cmd->init_task_tag,
639 			atomic_read(&cmd->response_queue_count));
640 	}
641 }
642 
643 bool iscsit_conn_all_queues_empty(struct iscsi_conn *conn)
644 {
645 	bool empty;
646 
647 	spin_lock_bh(&conn->immed_queue_lock);
648 	empty = list_empty(&conn->immed_queue_list);
649 	spin_unlock_bh(&conn->immed_queue_lock);
650 
651 	if (!empty)
652 		return empty;
653 
654 	spin_lock_bh(&conn->response_queue_lock);
655 	empty = list_empty(&conn->response_queue_list);
656 	spin_unlock_bh(&conn->response_queue_lock);
657 
658 	return empty;
659 }
660 
661 void iscsit_free_queue_reqs_for_conn(struct iscsi_conn *conn)
662 {
663 	struct iscsi_queue_req *qr, *qr_tmp;
664 
665 	spin_lock_bh(&conn->immed_queue_lock);
666 	list_for_each_entry_safe(qr, qr_tmp, &conn->immed_queue_list, qr_list) {
667 		list_del(&qr->qr_list);
668 		if (qr->cmd)
669 			atomic_dec(&qr->cmd->immed_queue_count);
670 
671 		kmem_cache_free(lio_qr_cache, qr);
672 	}
673 	spin_unlock_bh(&conn->immed_queue_lock);
674 
675 	spin_lock_bh(&conn->response_queue_lock);
676 	list_for_each_entry_safe(qr, qr_tmp, &conn->response_queue_list,
677 			qr_list) {
678 		list_del(&qr->qr_list);
679 		if (qr->cmd)
680 			atomic_dec(&qr->cmd->response_queue_count);
681 
682 		kmem_cache_free(lio_qr_cache, qr);
683 	}
684 	spin_unlock_bh(&conn->response_queue_lock);
685 }
686 
687 void iscsit_release_cmd(struct iscsi_cmd *cmd)
688 {
689 	struct iscsi_session *sess;
690 	struct se_cmd *se_cmd = &cmd->se_cmd;
691 
692 	if (cmd->conn)
693 		sess = cmd->conn->sess;
694 	else
695 		sess = cmd->sess;
696 
697 	BUG_ON(!sess || !sess->se_sess);
698 
699 	kfree(cmd->buf_ptr);
700 	kfree(cmd->pdu_list);
701 	kfree(cmd->seq_list);
702 	kfree(cmd->tmr_req);
703 	kfree(cmd->iov_data);
704 	kfree(cmd->text_in_ptr);
705 
706 	percpu_ida_free(&sess->se_sess->sess_tag_pool, se_cmd->map_tag);
707 }
708 EXPORT_SYMBOL(iscsit_release_cmd);
709 
710 void __iscsit_free_cmd(struct iscsi_cmd *cmd, bool scsi_cmd,
711 		       bool check_queues)
712 {
713 	struct iscsi_conn *conn = cmd->conn;
714 
715 	if (scsi_cmd) {
716 		if (cmd->data_direction == DMA_TO_DEVICE) {
717 			iscsit_stop_dataout_timer(cmd);
718 			iscsit_free_r2ts_from_list(cmd);
719 		}
720 		if (cmd->data_direction == DMA_FROM_DEVICE)
721 			iscsit_free_all_datain_reqs(cmd);
722 	}
723 
724 	if (conn && check_queues) {
725 		iscsit_remove_cmd_from_immediate_queue(cmd, conn);
726 		iscsit_remove_cmd_from_response_queue(cmd, conn);
727 	}
728 }
729 
730 void iscsit_free_cmd(struct iscsi_cmd *cmd, bool shutdown)
731 {
732 	struct se_cmd *se_cmd = NULL;
733 	int rc;
734 	/*
735 	 * Determine if a struct se_cmd is associated with
736 	 * this struct iscsi_cmd.
737 	 */
738 	switch (cmd->iscsi_opcode) {
739 	case ISCSI_OP_SCSI_CMD:
740 		se_cmd = &cmd->se_cmd;
741 		__iscsit_free_cmd(cmd, true, shutdown);
742 		/*
743 		 * Fallthrough
744 		 */
745 	case ISCSI_OP_SCSI_TMFUNC:
746 		rc = transport_generic_free_cmd(&cmd->se_cmd, shutdown);
747 		if (!rc && shutdown && se_cmd && se_cmd->se_sess) {
748 			__iscsit_free_cmd(cmd, true, shutdown);
749 			target_put_sess_cmd(se_cmd->se_sess, se_cmd);
750 		}
751 		break;
752 	case ISCSI_OP_REJECT:
753 		/*
754 		 * Handle special case for REJECT when iscsi_add_reject*() has
755 		 * overwritten the original iscsi_opcode assignment, and the
756 		 * associated cmd->se_cmd needs to be released.
757 		 */
758 		if (cmd->se_cmd.se_tfo != NULL) {
759 			se_cmd = &cmd->se_cmd;
760 			__iscsit_free_cmd(cmd, true, shutdown);
761 
762 			rc = transport_generic_free_cmd(&cmd->se_cmd, shutdown);
763 			if (!rc && shutdown && se_cmd->se_sess) {
764 				__iscsit_free_cmd(cmd, true, shutdown);
765 				target_put_sess_cmd(se_cmd->se_sess, se_cmd);
766 			}
767 			break;
768 		}
769 		/* Fall-through */
770 	default:
771 		__iscsit_free_cmd(cmd, false, shutdown);
772 		iscsit_release_cmd(cmd);
773 		break;
774 	}
775 }
776 
777 int iscsit_check_session_usage_count(struct iscsi_session *sess)
778 {
779 	spin_lock_bh(&sess->session_usage_lock);
780 	if (sess->session_usage_count != 0) {
781 		sess->session_waiting_on_uc = 1;
782 		spin_unlock_bh(&sess->session_usage_lock);
783 		if (in_interrupt())
784 			return 2;
785 
786 		wait_for_completion(&sess->session_waiting_on_uc_comp);
787 		return 1;
788 	}
789 	spin_unlock_bh(&sess->session_usage_lock);
790 
791 	return 0;
792 }
793 
794 void iscsit_dec_session_usage_count(struct iscsi_session *sess)
795 {
796 	spin_lock_bh(&sess->session_usage_lock);
797 	sess->session_usage_count--;
798 
799 	if (!sess->session_usage_count && sess->session_waiting_on_uc)
800 		complete(&sess->session_waiting_on_uc_comp);
801 
802 	spin_unlock_bh(&sess->session_usage_lock);
803 }
804 
805 void iscsit_inc_session_usage_count(struct iscsi_session *sess)
806 {
807 	spin_lock_bh(&sess->session_usage_lock);
808 	sess->session_usage_count++;
809 	spin_unlock_bh(&sess->session_usage_lock);
810 }
811 
812 /*
813  *	Setup conn->if_marker and conn->of_marker values based upon
814  *	the initial marker-less interval. (see iSCSI v19 A.2)
815  */
816 int iscsit_set_sync_and_steering_values(struct iscsi_conn *conn)
817 {
818 	int login_ifmarker_count = 0, login_ofmarker_count = 0, next_marker = 0;
819 	/*
820 	 * IFMarkInt and OFMarkInt are negotiated as 32-bit words.
821 	 */
822 	u32 IFMarkInt = (conn->conn_ops->IFMarkInt * 4);
823 	u32 OFMarkInt = (conn->conn_ops->OFMarkInt * 4);
824 
825 	if (conn->conn_ops->OFMarker) {
826 		/*
827 		 * Account for the first Login Command received not
828 		 * via iscsi_recv_msg().
829 		 */
830 		conn->of_marker += ISCSI_HDR_LEN;
831 		if (conn->of_marker <= OFMarkInt) {
832 			conn->of_marker = (OFMarkInt - conn->of_marker);
833 		} else {
834 			login_ofmarker_count = (conn->of_marker / OFMarkInt);
835 			next_marker = (OFMarkInt * (login_ofmarker_count + 1)) +
836 					(login_ofmarker_count * MARKER_SIZE);
837 			conn->of_marker = (next_marker - conn->of_marker);
838 		}
839 		conn->of_marker_offset = 0;
840 		pr_debug("Setting OFMarker value to %u based on Initial"
841 			" Markerless Interval.\n", conn->of_marker);
842 	}
843 
844 	if (conn->conn_ops->IFMarker) {
845 		if (conn->if_marker <= IFMarkInt) {
846 			conn->if_marker = (IFMarkInt - conn->if_marker);
847 		} else {
848 			login_ifmarker_count = (conn->if_marker / IFMarkInt);
849 			next_marker = (IFMarkInt * (login_ifmarker_count + 1)) +
850 					(login_ifmarker_count * MARKER_SIZE);
851 			conn->if_marker = (next_marker - conn->if_marker);
852 		}
853 		pr_debug("Setting IFMarker value to %u based on Initial"
854 			" Markerless Interval.\n", conn->if_marker);
855 	}
856 
857 	return 0;
858 }
859 
860 struct iscsi_conn *iscsit_get_conn_from_cid(struct iscsi_session *sess, u16 cid)
861 {
862 	struct iscsi_conn *conn;
863 
864 	spin_lock_bh(&sess->conn_lock);
865 	list_for_each_entry(conn, &sess->sess_conn_list, conn_list) {
866 		if ((conn->cid == cid) &&
867 		    (conn->conn_state == TARG_CONN_STATE_LOGGED_IN)) {
868 			iscsit_inc_conn_usage_count(conn);
869 			spin_unlock_bh(&sess->conn_lock);
870 			return conn;
871 		}
872 	}
873 	spin_unlock_bh(&sess->conn_lock);
874 
875 	return NULL;
876 }
877 
878 struct iscsi_conn *iscsit_get_conn_from_cid_rcfr(struct iscsi_session *sess, u16 cid)
879 {
880 	struct iscsi_conn *conn;
881 
882 	spin_lock_bh(&sess->conn_lock);
883 	list_for_each_entry(conn, &sess->sess_conn_list, conn_list) {
884 		if (conn->cid == cid) {
885 			iscsit_inc_conn_usage_count(conn);
886 			spin_lock(&conn->state_lock);
887 			atomic_set(&conn->connection_wait_rcfr, 1);
888 			spin_unlock(&conn->state_lock);
889 			spin_unlock_bh(&sess->conn_lock);
890 			return conn;
891 		}
892 	}
893 	spin_unlock_bh(&sess->conn_lock);
894 
895 	return NULL;
896 }
897 
898 void iscsit_check_conn_usage_count(struct iscsi_conn *conn)
899 {
900 	spin_lock_bh(&conn->conn_usage_lock);
901 	if (conn->conn_usage_count != 0) {
902 		conn->conn_waiting_on_uc = 1;
903 		spin_unlock_bh(&conn->conn_usage_lock);
904 
905 		wait_for_completion(&conn->conn_waiting_on_uc_comp);
906 		return;
907 	}
908 	spin_unlock_bh(&conn->conn_usage_lock);
909 }
910 
911 void iscsit_dec_conn_usage_count(struct iscsi_conn *conn)
912 {
913 	spin_lock_bh(&conn->conn_usage_lock);
914 	conn->conn_usage_count--;
915 
916 	if (!conn->conn_usage_count && conn->conn_waiting_on_uc)
917 		complete(&conn->conn_waiting_on_uc_comp);
918 
919 	spin_unlock_bh(&conn->conn_usage_lock);
920 }
921 
922 void iscsit_inc_conn_usage_count(struct iscsi_conn *conn)
923 {
924 	spin_lock_bh(&conn->conn_usage_lock);
925 	conn->conn_usage_count++;
926 	spin_unlock_bh(&conn->conn_usage_lock);
927 }
928 
929 static int iscsit_add_nopin(struct iscsi_conn *conn, int want_response)
930 {
931 	u8 state;
932 	struct iscsi_cmd *cmd;
933 
934 	cmd = iscsit_allocate_cmd(conn, TASK_RUNNING);
935 	if (!cmd)
936 		return -1;
937 
938 	cmd->iscsi_opcode = ISCSI_OP_NOOP_IN;
939 	state = (want_response) ? ISTATE_SEND_NOPIN_WANT_RESPONSE :
940 				ISTATE_SEND_NOPIN_NO_RESPONSE;
941 	cmd->init_task_tag = RESERVED_ITT;
942 	spin_lock_bh(&conn->sess->ttt_lock);
943 	cmd->targ_xfer_tag = (want_response) ? conn->sess->targ_xfer_tag++ :
944 			0xFFFFFFFF;
945 	if (want_response && (cmd->targ_xfer_tag == 0xFFFFFFFF))
946 		cmd->targ_xfer_tag = conn->sess->targ_xfer_tag++;
947 	spin_unlock_bh(&conn->sess->ttt_lock);
948 
949 	spin_lock_bh(&conn->cmd_lock);
950 	list_add_tail(&cmd->i_conn_node, &conn->conn_cmd_list);
951 	spin_unlock_bh(&conn->cmd_lock);
952 
953 	if (want_response)
954 		iscsit_start_nopin_response_timer(conn);
955 	iscsit_add_cmd_to_immediate_queue(cmd, conn, state);
956 
957 	return 0;
958 }
959 
960 static void iscsit_handle_nopin_response_timeout(unsigned long data)
961 {
962 	struct iscsi_conn *conn = (struct iscsi_conn *) data;
963 
964 	iscsit_inc_conn_usage_count(conn);
965 
966 	spin_lock_bh(&conn->nopin_timer_lock);
967 	if (conn->nopin_response_timer_flags & ISCSI_TF_STOP) {
968 		spin_unlock_bh(&conn->nopin_timer_lock);
969 		iscsit_dec_conn_usage_count(conn);
970 		return;
971 	}
972 
973 	pr_debug("Did not receive response to NOPIN on CID: %hu on"
974 		" SID: %u, failing connection.\n", conn->cid,
975 			conn->sess->sid);
976 	conn->nopin_response_timer_flags &= ~ISCSI_TF_RUNNING;
977 	spin_unlock_bh(&conn->nopin_timer_lock);
978 
979 	{
980 	struct iscsi_portal_group *tpg = conn->sess->tpg;
981 	struct iscsi_tiqn *tiqn = tpg->tpg_tiqn;
982 
983 	if (tiqn) {
984 		spin_lock_bh(&tiqn->sess_err_stats.lock);
985 		strcpy(tiqn->sess_err_stats.last_sess_fail_rem_name,
986 				conn->sess->sess_ops->InitiatorName);
987 		tiqn->sess_err_stats.last_sess_failure_type =
988 				ISCSI_SESS_ERR_CXN_TIMEOUT;
989 		tiqn->sess_err_stats.cxn_timeout_errors++;
990 		atomic_long_inc(&conn->sess->conn_timeout_errors);
991 		spin_unlock_bh(&tiqn->sess_err_stats.lock);
992 	}
993 	}
994 
995 	iscsit_cause_connection_reinstatement(conn, 0);
996 	iscsit_dec_conn_usage_count(conn);
997 }
998 
999 void iscsit_mod_nopin_response_timer(struct iscsi_conn *conn)
1000 {
1001 	struct iscsi_session *sess = conn->sess;
1002 	struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
1003 
1004 	spin_lock_bh(&conn->nopin_timer_lock);
1005 	if (!(conn->nopin_response_timer_flags & ISCSI_TF_RUNNING)) {
1006 		spin_unlock_bh(&conn->nopin_timer_lock);
1007 		return;
1008 	}
1009 
1010 	mod_timer(&conn->nopin_response_timer,
1011 		(get_jiffies_64() + na->nopin_response_timeout * HZ));
1012 	spin_unlock_bh(&conn->nopin_timer_lock);
1013 }
1014 
1015 /*
1016  *	Called with conn->nopin_timer_lock held.
1017  */
1018 void iscsit_start_nopin_response_timer(struct iscsi_conn *conn)
1019 {
1020 	struct iscsi_session *sess = conn->sess;
1021 	struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
1022 
1023 	spin_lock_bh(&conn->nopin_timer_lock);
1024 	if (conn->nopin_response_timer_flags & ISCSI_TF_RUNNING) {
1025 		spin_unlock_bh(&conn->nopin_timer_lock);
1026 		return;
1027 	}
1028 
1029 	init_timer(&conn->nopin_response_timer);
1030 	conn->nopin_response_timer.expires =
1031 		(get_jiffies_64() + na->nopin_response_timeout * HZ);
1032 	conn->nopin_response_timer.data = (unsigned long)conn;
1033 	conn->nopin_response_timer.function = iscsit_handle_nopin_response_timeout;
1034 	conn->nopin_response_timer_flags &= ~ISCSI_TF_STOP;
1035 	conn->nopin_response_timer_flags |= ISCSI_TF_RUNNING;
1036 	add_timer(&conn->nopin_response_timer);
1037 
1038 	pr_debug("Started NOPIN Response Timer on CID: %d to %u"
1039 		" seconds\n", conn->cid, na->nopin_response_timeout);
1040 	spin_unlock_bh(&conn->nopin_timer_lock);
1041 }
1042 
1043 void iscsit_stop_nopin_response_timer(struct iscsi_conn *conn)
1044 {
1045 	spin_lock_bh(&conn->nopin_timer_lock);
1046 	if (!(conn->nopin_response_timer_flags & ISCSI_TF_RUNNING)) {
1047 		spin_unlock_bh(&conn->nopin_timer_lock);
1048 		return;
1049 	}
1050 	conn->nopin_response_timer_flags |= ISCSI_TF_STOP;
1051 	spin_unlock_bh(&conn->nopin_timer_lock);
1052 
1053 	del_timer_sync(&conn->nopin_response_timer);
1054 
1055 	spin_lock_bh(&conn->nopin_timer_lock);
1056 	conn->nopin_response_timer_flags &= ~ISCSI_TF_RUNNING;
1057 	spin_unlock_bh(&conn->nopin_timer_lock);
1058 }
1059 
1060 static void iscsit_handle_nopin_timeout(unsigned long data)
1061 {
1062 	struct iscsi_conn *conn = (struct iscsi_conn *) data;
1063 
1064 	iscsit_inc_conn_usage_count(conn);
1065 
1066 	spin_lock_bh(&conn->nopin_timer_lock);
1067 	if (conn->nopin_timer_flags & ISCSI_TF_STOP) {
1068 		spin_unlock_bh(&conn->nopin_timer_lock);
1069 		iscsit_dec_conn_usage_count(conn);
1070 		return;
1071 	}
1072 	conn->nopin_timer_flags &= ~ISCSI_TF_RUNNING;
1073 	spin_unlock_bh(&conn->nopin_timer_lock);
1074 
1075 	iscsit_add_nopin(conn, 1);
1076 	iscsit_dec_conn_usage_count(conn);
1077 }
1078 
1079 /*
1080  * Called with conn->nopin_timer_lock held.
1081  */
1082 void __iscsit_start_nopin_timer(struct iscsi_conn *conn)
1083 {
1084 	struct iscsi_session *sess = conn->sess;
1085 	struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
1086 	/*
1087 	* NOPIN timeout is disabled.
1088 	 */
1089 	if (!na->nopin_timeout)
1090 		return;
1091 
1092 	if (conn->nopin_timer_flags & ISCSI_TF_RUNNING)
1093 		return;
1094 
1095 	init_timer(&conn->nopin_timer);
1096 	conn->nopin_timer.expires = (get_jiffies_64() + na->nopin_timeout * HZ);
1097 	conn->nopin_timer.data = (unsigned long)conn;
1098 	conn->nopin_timer.function = iscsit_handle_nopin_timeout;
1099 	conn->nopin_timer_flags &= ~ISCSI_TF_STOP;
1100 	conn->nopin_timer_flags |= ISCSI_TF_RUNNING;
1101 	add_timer(&conn->nopin_timer);
1102 
1103 	pr_debug("Started NOPIN Timer on CID: %d at %u second"
1104 		" interval\n", conn->cid, na->nopin_timeout);
1105 }
1106 
1107 void iscsit_start_nopin_timer(struct iscsi_conn *conn)
1108 {
1109 	struct iscsi_session *sess = conn->sess;
1110 	struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
1111 	/*
1112 	 * NOPIN timeout is disabled..
1113 	 */
1114 	if (!na->nopin_timeout)
1115 		return;
1116 
1117 	spin_lock_bh(&conn->nopin_timer_lock);
1118 	if (conn->nopin_timer_flags & ISCSI_TF_RUNNING) {
1119 		spin_unlock_bh(&conn->nopin_timer_lock);
1120 		return;
1121 	}
1122 
1123 	init_timer(&conn->nopin_timer);
1124 	conn->nopin_timer.expires = (get_jiffies_64() + na->nopin_timeout * HZ);
1125 	conn->nopin_timer.data = (unsigned long)conn;
1126 	conn->nopin_timer.function = iscsit_handle_nopin_timeout;
1127 	conn->nopin_timer_flags &= ~ISCSI_TF_STOP;
1128 	conn->nopin_timer_flags |= ISCSI_TF_RUNNING;
1129 	add_timer(&conn->nopin_timer);
1130 
1131 	pr_debug("Started NOPIN Timer on CID: %d at %u second"
1132 			" interval\n", conn->cid, na->nopin_timeout);
1133 	spin_unlock_bh(&conn->nopin_timer_lock);
1134 }
1135 
1136 void iscsit_stop_nopin_timer(struct iscsi_conn *conn)
1137 {
1138 	spin_lock_bh(&conn->nopin_timer_lock);
1139 	if (!(conn->nopin_timer_flags & ISCSI_TF_RUNNING)) {
1140 		spin_unlock_bh(&conn->nopin_timer_lock);
1141 		return;
1142 	}
1143 	conn->nopin_timer_flags |= ISCSI_TF_STOP;
1144 	spin_unlock_bh(&conn->nopin_timer_lock);
1145 
1146 	del_timer_sync(&conn->nopin_timer);
1147 
1148 	spin_lock_bh(&conn->nopin_timer_lock);
1149 	conn->nopin_timer_flags &= ~ISCSI_TF_RUNNING;
1150 	spin_unlock_bh(&conn->nopin_timer_lock);
1151 }
1152 
1153 int iscsit_send_tx_data(
1154 	struct iscsi_cmd *cmd,
1155 	struct iscsi_conn *conn,
1156 	int use_misc)
1157 {
1158 	int tx_sent, tx_size;
1159 	u32 iov_count;
1160 	struct kvec *iov;
1161 
1162 send_data:
1163 	tx_size = cmd->tx_size;
1164 
1165 	if (!use_misc) {
1166 		iov = &cmd->iov_data[0];
1167 		iov_count = cmd->iov_data_count;
1168 	} else {
1169 		iov = &cmd->iov_misc[0];
1170 		iov_count = cmd->iov_misc_count;
1171 	}
1172 
1173 	tx_sent = tx_data(conn, &iov[0], iov_count, tx_size);
1174 	if (tx_size != tx_sent) {
1175 		if (tx_sent == -EAGAIN) {
1176 			pr_err("tx_data() returned -EAGAIN\n");
1177 			goto send_data;
1178 		} else
1179 			return -1;
1180 	}
1181 	cmd->tx_size = 0;
1182 
1183 	return 0;
1184 }
1185 
1186 int iscsit_fe_sendpage_sg(
1187 	struct iscsi_cmd *cmd,
1188 	struct iscsi_conn *conn)
1189 {
1190 	struct scatterlist *sg = cmd->first_data_sg;
1191 	struct kvec iov;
1192 	u32 tx_hdr_size, data_len;
1193 	u32 offset = cmd->first_data_sg_off;
1194 	int tx_sent, iov_off;
1195 
1196 send_hdr:
1197 	tx_hdr_size = ISCSI_HDR_LEN;
1198 	if (conn->conn_ops->HeaderDigest)
1199 		tx_hdr_size += ISCSI_CRC_LEN;
1200 
1201 	iov.iov_base = cmd->pdu;
1202 	iov.iov_len = tx_hdr_size;
1203 
1204 	tx_sent = tx_data(conn, &iov, 1, tx_hdr_size);
1205 	if (tx_hdr_size != tx_sent) {
1206 		if (tx_sent == -EAGAIN) {
1207 			pr_err("tx_data() returned -EAGAIN\n");
1208 			goto send_hdr;
1209 		}
1210 		return -1;
1211 	}
1212 
1213 	data_len = cmd->tx_size - tx_hdr_size - cmd->padding;
1214 	/*
1215 	 * Set iov_off used by padding and data digest tx_data() calls below
1216 	 * in order to determine proper offset into cmd->iov_data[]
1217 	 */
1218 	if (conn->conn_ops->DataDigest) {
1219 		data_len -= ISCSI_CRC_LEN;
1220 		if (cmd->padding)
1221 			iov_off = (cmd->iov_data_count - 2);
1222 		else
1223 			iov_off = (cmd->iov_data_count - 1);
1224 	} else {
1225 		iov_off = (cmd->iov_data_count - 1);
1226 	}
1227 	/*
1228 	 * Perform sendpage() for each page in the scatterlist
1229 	 */
1230 	while (data_len) {
1231 		u32 space = (sg->length - offset);
1232 		u32 sub_len = min_t(u32, data_len, space);
1233 send_pg:
1234 		tx_sent = conn->sock->ops->sendpage(conn->sock,
1235 					sg_page(sg), sg->offset + offset, sub_len, 0);
1236 		if (tx_sent != sub_len) {
1237 			if (tx_sent == -EAGAIN) {
1238 				pr_err("tcp_sendpage() returned"
1239 						" -EAGAIN\n");
1240 				goto send_pg;
1241 			}
1242 
1243 			pr_err("tcp_sendpage() failure: %d\n",
1244 					tx_sent);
1245 			return -1;
1246 		}
1247 
1248 		data_len -= sub_len;
1249 		offset = 0;
1250 		sg = sg_next(sg);
1251 	}
1252 
1253 send_padding:
1254 	if (cmd->padding) {
1255 		struct kvec *iov_p = &cmd->iov_data[iov_off++];
1256 
1257 		tx_sent = tx_data(conn, iov_p, 1, cmd->padding);
1258 		if (cmd->padding != tx_sent) {
1259 			if (tx_sent == -EAGAIN) {
1260 				pr_err("tx_data() returned -EAGAIN\n");
1261 				goto send_padding;
1262 			}
1263 			return -1;
1264 		}
1265 	}
1266 
1267 send_datacrc:
1268 	if (conn->conn_ops->DataDigest) {
1269 		struct kvec *iov_d = &cmd->iov_data[iov_off];
1270 
1271 		tx_sent = tx_data(conn, iov_d, 1, ISCSI_CRC_LEN);
1272 		if (ISCSI_CRC_LEN != tx_sent) {
1273 			if (tx_sent == -EAGAIN) {
1274 				pr_err("tx_data() returned -EAGAIN\n");
1275 				goto send_datacrc;
1276 			}
1277 			return -1;
1278 		}
1279 	}
1280 
1281 	return 0;
1282 }
1283 
1284 /*
1285  *      This function is used for mainly sending a ISCSI_TARG_LOGIN_RSP PDU
1286  *      back to the Initiator when an expection condition occurs with the
1287  *      errors set in status_class and status_detail.
1288  *
1289  *      Parameters:     iSCSI Connection, Status Class, Status Detail.
1290  *      Returns:        0 on success, -1 on error.
1291  */
1292 int iscsit_tx_login_rsp(struct iscsi_conn *conn, u8 status_class, u8 status_detail)
1293 {
1294 	struct iscsi_login_rsp *hdr;
1295 	struct iscsi_login *login = conn->conn_login;
1296 
1297 	login->login_failed = 1;
1298 	iscsit_collect_login_stats(conn, status_class, status_detail);
1299 
1300 	memset(&login->rsp[0], 0, ISCSI_HDR_LEN);
1301 
1302 	hdr	= (struct iscsi_login_rsp *)&login->rsp[0];
1303 	hdr->opcode		= ISCSI_OP_LOGIN_RSP;
1304 	hdr->status_class	= status_class;
1305 	hdr->status_detail	= status_detail;
1306 	hdr->itt		= conn->login_itt;
1307 
1308 	return conn->conn_transport->iscsit_put_login_tx(conn, login, 0);
1309 }
1310 
1311 void iscsit_print_session_params(struct iscsi_session *sess)
1312 {
1313 	struct iscsi_conn *conn;
1314 
1315 	pr_debug("-----------------------------[Session Params for"
1316 		" SID: %u]-----------------------------\n", sess->sid);
1317 	spin_lock_bh(&sess->conn_lock);
1318 	list_for_each_entry(conn, &sess->sess_conn_list, conn_list)
1319 		iscsi_dump_conn_ops(conn->conn_ops);
1320 	spin_unlock_bh(&sess->conn_lock);
1321 
1322 	iscsi_dump_sess_ops(sess->sess_ops);
1323 }
1324 
1325 static int iscsit_do_rx_data(
1326 	struct iscsi_conn *conn,
1327 	struct iscsi_data_count *count)
1328 {
1329 	int data = count->data_length, rx_loop = 0, total_rx = 0, iov_len;
1330 	struct kvec *iov_p;
1331 	struct msghdr msg;
1332 
1333 	if (!conn || !conn->sock || !conn->conn_ops)
1334 		return -1;
1335 
1336 	memset(&msg, 0, sizeof(struct msghdr));
1337 
1338 	iov_p = count->iov;
1339 	iov_len	= count->iov_count;
1340 
1341 	while (total_rx < data) {
1342 		rx_loop = kernel_recvmsg(conn->sock, &msg, iov_p, iov_len,
1343 					(data - total_rx), MSG_WAITALL);
1344 		if (rx_loop <= 0) {
1345 			pr_debug("rx_loop: %d total_rx: %d\n",
1346 				rx_loop, total_rx);
1347 			return rx_loop;
1348 		}
1349 		total_rx += rx_loop;
1350 		pr_debug("rx_loop: %d, total_rx: %d, data: %d\n",
1351 				rx_loop, total_rx, data);
1352 	}
1353 
1354 	return total_rx;
1355 }
1356 
1357 static int iscsit_do_tx_data(
1358 	struct iscsi_conn *conn,
1359 	struct iscsi_data_count *count)
1360 {
1361 	int data = count->data_length, total_tx = 0, tx_loop = 0, iov_len;
1362 	struct kvec *iov_p;
1363 	struct msghdr msg;
1364 
1365 	if (!conn || !conn->sock || !conn->conn_ops)
1366 		return -1;
1367 
1368 	if (data <= 0) {
1369 		pr_err("Data length is: %d\n", data);
1370 		return -1;
1371 	}
1372 
1373 	memset(&msg, 0, sizeof(struct msghdr));
1374 
1375 	iov_p = count->iov;
1376 	iov_len = count->iov_count;
1377 
1378 	while (total_tx < data) {
1379 		tx_loop = kernel_sendmsg(conn->sock, &msg, iov_p, iov_len,
1380 					(data - total_tx));
1381 		if (tx_loop <= 0) {
1382 			pr_debug("tx_loop: %d total_tx %d\n",
1383 				tx_loop, total_tx);
1384 			return tx_loop;
1385 		}
1386 		total_tx += tx_loop;
1387 		pr_debug("tx_loop: %d, total_tx: %d, data: %d\n",
1388 					tx_loop, total_tx, data);
1389 	}
1390 
1391 	return total_tx;
1392 }
1393 
1394 int rx_data(
1395 	struct iscsi_conn *conn,
1396 	struct kvec *iov,
1397 	int iov_count,
1398 	int data)
1399 {
1400 	struct iscsi_data_count c;
1401 
1402 	if (!conn || !conn->sock || !conn->conn_ops)
1403 		return -1;
1404 
1405 	memset(&c, 0, sizeof(struct iscsi_data_count));
1406 	c.iov = iov;
1407 	c.iov_count = iov_count;
1408 	c.data_length = data;
1409 	c.type = ISCSI_RX_DATA;
1410 
1411 	return iscsit_do_rx_data(conn, &c);
1412 }
1413 
1414 int tx_data(
1415 	struct iscsi_conn *conn,
1416 	struct kvec *iov,
1417 	int iov_count,
1418 	int data)
1419 {
1420 	struct iscsi_data_count c;
1421 
1422 	if (!conn || !conn->sock || !conn->conn_ops)
1423 		return -1;
1424 
1425 	memset(&c, 0, sizeof(struct iscsi_data_count));
1426 	c.iov = iov;
1427 	c.iov_count = iov_count;
1428 	c.data_length = data;
1429 	c.type = ISCSI_TX_DATA;
1430 
1431 	return iscsit_do_tx_data(conn, &c);
1432 }
1433 
1434 void iscsit_collect_login_stats(
1435 	struct iscsi_conn *conn,
1436 	u8 status_class,
1437 	u8 status_detail)
1438 {
1439 	struct iscsi_param *intrname = NULL;
1440 	struct iscsi_tiqn *tiqn;
1441 	struct iscsi_login_stats *ls;
1442 
1443 	tiqn = iscsit_snmp_get_tiqn(conn);
1444 	if (!tiqn)
1445 		return;
1446 
1447 	ls = &tiqn->login_stats;
1448 
1449 	spin_lock(&ls->lock);
1450 	if (!strcmp(conn->login_ip, ls->last_intr_fail_ip_addr) &&
1451 	    ((get_jiffies_64() - ls->last_fail_time) < 10)) {
1452 		/* We already have the failure info for this login */
1453 		spin_unlock(&ls->lock);
1454 		return;
1455 	}
1456 
1457 	if (status_class == ISCSI_STATUS_CLS_SUCCESS)
1458 		ls->accepts++;
1459 	else if (status_class == ISCSI_STATUS_CLS_REDIRECT) {
1460 		ls->redirects++;
1461 		ls->last_fail_type = ISCSI_LOGIN_FAIL_REDIRECT;
1462 	} else if ((status_class == ISCSI_STATUS_CLS_INITIATOR_ERR)  &&
1463 		 (status_detail == ISCSI_LOGIN_STATUS_AUTH_FAILED)) {
1464 		ls->authenticate_fails++;
1465 		ls->last_fail_type =  ISCSI_LOGIN_FAIL_AUTHENTICATE;
1466 	} else if ((status_class == ISCSI_STATUS_CLS_INITIATOR_ERR)  &&
1467 		 (status_detail == ISCSI_LOGIN_STATUS_TGT_FORBIDDEN)) {
1468 		ls->authorize_fails++;
1469 		ls->last_fail_type = ISCSI_LOGIN_FAIL_AUTHORIZE;
1470 	} else if ((status_class == ISCSI_STATUS_CLS_INITIATOR_ERR) &&
1471 		 (status_detail == ISCSI_LOGIN_STATUS_INIT_ERR)) {
1472 		ls->negotiate_fails++;
1473 		ls->last_fail_type = ISCSI_LOGIN_FAIL_NEGOTIATE;
1474 	} else {
1475 		ls->other_fails++;
1476 		ls->last_fail_type = ISCSI_LOGIN_FAIL_OTHER;
1477 	}
1478 
1479 	/* Save initiator name, ip address and time, if it is a failed login */
1480 	if (status_class != ISCSI_STATUS_CLS_SUCCESS) {
1481 		if (conn->param_list)
1482 			intrname = iscsi_find_param_from_key(INITIATORNAME,
1483 							     conn->param_list);
1484 		strlcpy(ls->last_intr_fail_name,
1485 		       (intrname ? intrname->value : "Unknown"),
1486 		       sizeof(ls->last_intr_fail_name));
1487 
1488 		ls->last_intr_fail_ip_family = conn->login_family;
1489 
1490 		snprintf(ls->last_intr_fail_ip_addr, IPV6_ADDRESS_SPACE,
1491 				"%s", conn->login_ip);
1492 		ls->last_fail_time = get_jiffies_64();
1493 	}
1494 
1495 	spin_unlock(&ls->lock);
1496 }
1497 
1498 struct iscsi_tiqn *iscsit_snmp_get_tiqn(struct iscsi_conn *conn)
1499 {
1500 	struct iscsi_portal_group *tpg;
1501 
1502 	if (!conn || !conn->sess)
1503 		return NULL;
1504 
1505 	tpg = conn->sess->tpg;
1506 	if (!tpg)
1507 		return NULL;
1508 
1509 	if (!tpg->tpg_tiqn)
1510 		return NULL;
1511 
1512 	return tpg->tpg_tiqn;
1513 }
1514