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 <target/iscsi/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 EXPORT_SYMBOL(iscsit_find_cmd_from_itt);
394 
395 struct iscsi_cmd *iscsit_find_cmd_from_itt_or_dump(
396 	struct iscsi_conn *conn,
397 	itt_t init_task_tag,
398 	u32 length)
399 {
400 	struct iscsi_cmd *cmd;
401 
402 	spin_lock_bh(&conn->cmd_lock);
403 	list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
404 		if (cmd->cmd_flags & ICF_GOT_LAST_DATAOUT)
405 			continue;
406 		if (cmd->init_task_tag == init_task_tag) {
407 			spin_unlock_bh(&conn->cmd_lock);
408 			return cmd;
409 		}
410 	}
411 	spin_unlock_bh(&conn->cmd_lock);
412 
413 	pr_err("Unable to locate ITT: 0x%08x on CID: %hu,"
414 			" dumping payload\n", init_task_tag, conn->cid);
415 	if (length)
416 		iscsit_dump_data_payload(conn, length, 1);
417 
418 	return NULL;
419 }
420 
421 struct iscsi_cmd *iscsit_find_cmd_from_ttt(
422 	struct iscsi_conn *conn,
423 	u32 targ_xfer_tag)
424 {
425 	struct iscsi_cmd *cmd = NULL;
426 
427 	spin_lock_bh(&conn->cmd_lock);
428 	list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
429 		if (cmd->targ_xfer_tag == targ_xfer_tag) {
430 			spin_unlock_bh(&conn->cmd_lock);
431 			return cmd;
432 		}
433 	}
434 	spin_unlock_bh(&conn->cmd_lock);
435 
436 	pr_err("Unable to locate TTT: 0x%08x on CID: %hu\n",
437 			targ_xfer_tag, conn->cid);
438 	return NULL;
439 }
440 
441 int iscsit_find_cmd_for_recovery(
442 	struct iscsi_session *sess,
443 	struct iscsi_cmd **cmd_ptr,
444 	struct iscsi_conn_recovery **cr_ptr,
445 	itt_t init_task_tag)
446 {
447 	struct iscsi_cmd *cmd = NULL;
448 	struct iscsi_conn_recovery *cr;
449 	/*
450 	 * Scan through the inactive connection recovery list's command list.
451 	 * If init_task_tag matches the command is still alligent.
452 	 */
453 	spin_lock(&sess->cr_i_lock);
454 	list_for_each_entry(cr, &sess->cr_inactive_list, cr_list) {
455 		spin_lock(&cr->conn_recovery_cmd_lock);
456 		list_for_each_entry(cmd, &cr->conn_recovery_cmd_list, i_conn_node) {
457 			if (cmd->init_task_tag == init_task_tag) {
458 				spin_unlock(&cr->conn_recovery_cmd_lock);
459 				spin_unlock(&sess->cr_i_lock);
460 
461 				*cr_ptr = cr;
462 				*cmd_ptr = cmd;
463 				return -2;
464 			}
465 		}
466 		spin_unlock(&cr->conn_recovery_cmd_lock);
467 	}
468 	spin_unlock(&sess->cr_i_lock);
469 	/*
470 	 * Scan through the active connection recovery list's command list.
471 	 * If init_task_tag matches the command is ready to be reassigned.
472 	 */
473 	spin_lock(&sess->cr_a_lock);
474 	list_for_each_entry(cr, &sess->cr_active_list, cr_list) {
475 		spin_lock(&cr->conn_recovery_cmd_lock);
476 		list_for_each_entry(cmd, &cr->conn_recovery_cmd_list, i_conn_node) {
477 			if (cmd->init_task_tag == init_task_tag) {
478 				spin_unlock(&cr->conn_recovery_cmd_lock);
479 				spin_unlock(&sess->cr_a_lock);
480 
481 				*cr_ptr = cr;
482 				*cmd_ptr = cmd;
483 				return 0;
484 			}
485 		}
486 		spin_unlock(&cr->conn_recovery_cmd_lock);
487 	}
488 	spin_unlock(&sess->cr_a_lock);
489 
490 	return -1;
491 }
492 
493 void iscsit_add_cmd_to_immediate_queue(
494 	struct iscsi_cmd *cmd,
495 	struct iscsi_conn *conn,
496 	u8 state)
497 {
498 	struct iscsi_queue_req *qr;
499 
500 	qr = kmem_cache_zalloc(lio_qr_cache, GFP_ATOMIC);
501 	if (!qr) {
502 		pr_err("Unable to allocate memory for"
503 				" struct iscsi_queue_req\n");
504 		return;
505 	}
506 	INIT_LIST_HEAD(&qr->qr_list);
507 	qr->cmd = cmd;
508 	qr->state = state;
509 
510 	spin_lock_bh(&conn->immed_queue_lock);
511 	list_add_tail(&qr->qr_list, &conn->immed_queue_list);
512 	atomic_inc(&cmd->immed_queue_count);
513 	atomic_set(&conn->check_immediate_queue, 1);
514 	spin_unlock_bh(&conn->immed_queue_lock);
515 
516 	wake_up(&conn->queues_wq);
517 }
518 
519 struct iscsi_queue_req *iscsit_get_cmd_from_immediate_queue(struct iscsi_conn *conn)
520 {
521 	struct iscsi_queue_req *qr;
522 
523 	spin_lock_bh(&conn->immed_queue_lock);
524 	if (list_empty(&conn->immed_queue_list)) {
525 		spin_unlock_bh(&conn->immed_queue_lock);
526 		return NULL;
527 	}
528 	qr = list_first_entry(&conn->immed_queue_list,
529 			      struct iscsi_queue_req, qr_list);
530 
531 	list_del(&qr->qr_list);
532 	if (qr->cmd)
533 		atomic_dec(&qr->cmd->immed_queue_count);
534 	spin_unlock_bh(&conn->immed_queue_lock);
535 
536 	return qr;
537 }
538 
539 static void iscsit_remove_cmd_from_immediate_queue(
540 	struct iscsi_cmd *cmd,
541 	struct iscsi_conn *conn)
542 {
543 	struct iscsi_queue_req *qr, *qr_tmp;
544 
545 	spin_lock_bh(&conn->immed_queue_lock);
546 	if (!atomic_read(&cmd->immed_queue_count)) {
547 		spin_unlock_bh(&conn->immed_queue_lock);
548 		return;
549 	}
550 
551 	list_for_each_entry_safe(qr, qr_tmp, &conn->immed_queue_list, qr_list) {
552 		if (qr->cmd != cmd)
553 			continue;
554 
555 		atomic_dec(&qr->cmd->immed_queue_count);
556 		list_del(&qr->qr_list);
557 		kmem_cache_free(lio_qr_cache, qr);
558 	}
559 	spin_unlock_bh(&conn->immed_queue_lock);
560 
561 	if (atomic_read(&cmd->immed_queue_count)) {
562 		pr_err("ITT: 0x%08x immed_queue_count: %d\n",
563 			cmd->init_task_tag,
564 			atomic_read(&cmd->immed_queue_count));
565 	}
566 }
567 
568 void iscsit_add_cmd_to_response_queue(
569 	struct iscsi_cmd *cmd,
570 	struct iscsi_conn *conn,
571 	u8 state)
572 {
573 	struct iscsi_queue_req *qr;
574 
575 	qr = kmem_cache_zalloc(lio_qr_cache, GFP_ATOMIC);
576 	if (!qr) {
577 		pr_err("Unable to allocate memory for"
578 			" struct iscsi_queue_req\n");
579 		return;
580 	}
581 	INIT_LIST_HEAD(&qr->qr_list);
582 	qr->cmd = cmd;
583 	qr->state = state;
584 
585 	spin_lock_bh(&conn->response_queue_lock);
586 	list_add_tail(&qr->qr_list, &conn->response_queue_list);
587 	atomic_inc(&cmd->response_queue_count);
588 	spin_unlock_bh(&conn->response_queue_lock);
589 
590 	wake_up(&conn->queues_wq);
591 }
592 
593 struct iscsi_queue_req *iscsit_get_cmd_from_response_queue(struct iscsi_conn *conn)
594 {
595 	struct iscsi_queue_req *qr;
596 
597 	spin_lock_bh(&conn->response_queue_lock);
598 	if (list_empty(&conn->response_queue_list)) {
599 		spin_unlock_bh(&conn->response_queue_lock);
600 		return NULL;
601 	}
602 
603 	qr = list_first_entry(&conn->response_queue_list,
604 			      struct iscsi_queue_req, qr_list);
605 
606 	list_del(&qr->qr_list);
607 	if (qr->cmd)
608 		atomic_dec(&qr->cmd->response_queue_count);
609 	spin_unlock_bh(&conn->response_queue_lock);
610 
611 	return qr;
612 }
613 
614 static void iscsit_remove_cmd_from_response_queue(
615 	struct iscsi_cmd *cmd,
616 	struct iscsi_conn *conn)
617 {
618 	struct iscsi_queue_req *qr, *qr_tmp;
619 
620 	spin_lock_bh(&conn->response_queue_lock);
621 	if (!atomic_read(&cmd->response_queue_count)) {
622 		spin_unlock_bh(&conn->response_queue_lock);
623 		return;
624 	}
625 
626 	list_for_each_entry_safe(qr, qr_tmp, &conn->response_queue_list,
627 				qr_list) {
628 		if (qr->cmd != cmd)
629 			continue;
630 
631 		atomic_dec(&qr->cmd->response_queue_count);
632 		list_del(&qr->qr_list);
633 		kmem_cache_free(lio_qr_cache, qr);
634 	}
635 	spin_unlock_bh(&conn->response_queue_lock);
636 
637 	if (atomic_read(&cmd->response_queue_count)) {
638 		pr_err("ITT: 0x%08x response_queue_count: %d\n",
639 			cmd->init_task_tag,
640 			atomic_read(&cmd->response_queue_count));
641 	}
642 }
643 
644 bool iscsit_conn_all_queues_empty(struct iscsi_conn *conn)
645 {
646 	bool empty;
647 
648 	spin_lock_bh(&conn->immed_queue_lock);
649 	empty = list_empty(&conn->immed_queue_list);
650 	spin_unlock_bh(&conn->immed_queue_lock);
651 
652 	if (!empty)
653 		return empty;
654 
655 	spin_lock_bh(&conn->response_queue_lock);
656 	empty = list_empty(&conn->response_queue_list);
657 	spin_unlock_bh(&conn->response_queue_lock);
658 
659 	return empty;
660 }
661 
662 void iscsit_free_queue_reqs_for_conn(struct iscsi_conn *conn)
663 {
664 	struct iscsi_queue_req *qr, *qr_tmp;
665 
666 	spin_lock_bh(&conn->immed_queue_lock);
667 	list_for_each_entry_safe(qr, qr_tmp, &conn->immed_queue_list, qr_list) {
668 		list_del(&qr->qr_list);
669 		if (qr->cmd)
670 			atomic_dec(&qr->cmd->immed_queue_count);
671 
672 		kmem_cache_free(lio_qr_cache, qr);
673 	}
674 	spin_unlock_bh(&conn->immed_queue_lock);
675 
676 	spin_lock_bh(&conn->response_queue_lock);
677 	list_for_each_entry_safe(qr, qr_tmp, &conn->response_queue_list,
678 			qr_list) {
679 		list_del(&qr->qr_list);
680 		if (qr->cmd)
681 			atomic_dec(&qr->cmd->response_queue_count);
682 
683 		kmem_cache_free(lio_qr_cache, qr);
684 	}
685 	spin_unlock_bh(&conn->response_queue_lock);
686 }
687 
688 void iscsit_release_cmd(struct iscsi_cmd *cmd)
689 {
690 	struct iscsi_session *sess;
691 	struct se_cmd *se_cmd = &cmd->se_cmd;
692 
693 	if (cmd->conn)
694 		sess = cmd->conn->sess;
695 	else
696 		sess = cmd->sess;
697 
698 	BUG_ON(!sess || !sess->se_sess);
699 
700 	kfree(cmd->buf_ptr);
701 	kfree(cmd->pdu_list);
702 	kfree(cmd->seq_list);
703 	kfree(cmd->tmr_req);
704 	kfree(cmd->iov_data);
705 	kfree(cmd->text_in_ptr);
706 
707 	percpu_ida_free(&sess->se_sess->sess_tag_pool, se_cmd->map_tag);
708 }
709 EXPORT_SYMBOL(iscsit_release_cmd);
710 
711 void __iscsit_free_cmd(struct iscsi_cmd *cmd, bool scsi_cmd,
712 		       bool check_queues)
713 {
714 	struct iscsi_conn *conn = cmd->conn;
715 
716 	if (scsi_cmd) {
717 		if (cmd->data_direction == DMA_TO_DEVICE) {
718 			iscsit_stop_dataout_timer(cmd);
719 			iscsit_free_r2ts_from_list(cmd);
720 		}
721 		if (cmd->data_direction == DMA_FROM_DEVICE)
722 			iscsit_free_all_datain_reqs(cmd);
723 	}
724 
725 	if (conn && check_queues) {
726 		iscsit_remove_cmd_from_immediate_queue(cmd, conn);
727 		iscsit_remove_cmd_from_response_queue(cmd, conn);
728 	}
729 }
730 
731 void iscsit_free_cmd(struct iscsi_cmd *cmd, bool shutdown)
732 {
733 	struct se_cmd *se_cmd = NULL;
734 	int rc;
735 	/*
736 	 * Determine if a struct se_cmd is associated with
737 	 * this struct iscsi_cmd.
738 	 */
739 	switch (cmd->iscsi_opcode) {
740 	case ISCSI_OP_SCSI_CMD:
741 		se_cmd = &cmd->se_cmd;
742 		__iscsit_free_cmd(cmd, true, shutdown);
743 		/*
744 		 * Fallthrough
745 		 */
746 	case ISCSI_OP_SCSI_TMFUNC:
747 		rc = transport_generic_free_cmd(&cmd->se_cmd, shutdown);
748 		if (!rc && shutdown && se_cmd && se_cmd->se_sess) {
749 			__iscsit_free_cmd(cmd, true, shutdown);
750 			target_put_sess_cmd(se_cmd->se_sess, se_cmd);
751 		}
752 		break;
753 	case ISCSI_OP_REJECT:
754 		/*
755 		 * Handle special case for REJECT when iscsi_add_reject*() has
756 		 * overwritten the original iscsi_opcode assignment, and the
757 		 * associated cmd->se_cmd needs to be released.
758 		 */
759 		if (cmd->se_cmd.se_tfo != NULL) {
760 			se_cmd = &cmd->se_cmd;
761 			__iscsit_free_cmd(cmd, true, shutdown);
762 
763 			rc = transport_generic_free_cmd(&cmd->se_cmd, shutdown);
764 			if (!rc && shutdown && se_cmd->se_sess) {
765 				__iscsit_free_cmd(cmd, true, shutdown);
766 				target_put_sess_cmd(se_cmd->se_sess, se_cmd);
767 			}
768 			break;
769 		}
770 		/* Fall-through */
771 	default:
772 		__iscsit_free_cmd(cmd, false, shutdown);
773 		iscsit_release_cmd(cmd);
774 		break;
775 	}
776 }
777 
778 int iscsit_check_session_usage_count(struct iscsi_session *sess)
779 {
780 	spin_lock_bh(&sess->session_usage_lock);
781 	if (sess->session_usage_count != 0) {
782 		sess->session_waiting_on_uc = 1;
783 		spin_unlock_bh(&sess->session_usage_lock);
784 		if (in_interrupt())
785 			return 2;
786 
787 		wait_for_completion(&sess->session_waiting_on_uc_comp);
788 		return 1;
789 	}
790 	spin_unlock_bh(&sess->session_usage_lock);
791 
792 	return 0;
793 }
794 
795 void iscsit_dec_session_usage_count(struct iscsi_session *sess)
796 {
797 	spin_lock_bh(&sess->session_usage_lock);
798 	sess->session_usage_count--;
799 
800 	if (!sess->session_usage_count && sess->session_waiting_on_uc)
801 		complete(&sess->session_waiting_on_uc_comp);
802 
803 	spin_unlock_bh(&sess->session_usage_lock);
804 }
805 
806 void iscsit_inc_session_usage_count(struct iscsi_session *sess)
807 {
808 	spin_lock_bh(&sess->session_usage_lock);
809 	sess->session_usage_count++;
810 	spin_unlock_bh(&sess->session_usage_lock);
811 }
812 
813 /*
814  *	Setup conn->if_marker and conn->of_marker values based upon
815  *	the initial marker-less interval. (see iSCSI v19 A.2)
816  */
817 int iscsit_set_sync_and_steering_values(struct iscsi_conn *conn)
818 {
819 	int login_ifmarker_count = 0, login_ofmarker_count = 0, next_marker = 0;
820 	/*
821 	 * IFMarkInt and OFMarkInt are negotiated as 32-bit words.
822 	 */
823 	u32 IFMarkInt = (conn->conn_ops->IFMarkInt * 4);
824 	u32 OFMarkInt = (conn->conn_ops->OFMarkInt * 4);
825 
826 	if (conn->conn_ops->OFMarker) {
827 		/*
828 		 * Account for the first Login Command received not
829 		 * via iscsi_recv_msg().
830 		 */
831 		conn->of_marker += ISCSI_HDR_LEN;
832 		if (conn->of_marker <= OFMarkInt) {
833 			conn->of_marker = (OFMarkInt - conn->of_marker);
834 		} else {
835 			login_ofmarker_count = (conn->of_marker / OFMarkInt);
836 			next_marker = (OFMarkInt * (login_ofmarker_count + 1)) +
837 					(login_ofmarker_count * MARKER_SIZE);
838 			conn->of_marker = (next_marker - conn->of_marker);
839 		}
840 		conn->of_marker_offset = 0;
841 		pr_debug("Setting OFMarker value to %u based on Initial"
842 			" Markerless Interval.\n", conn->of_marker);
843 	}
844 
845 	if (conn->conn_ops->IFMarker) {
846 		if (conn->if_marker <= IFMarkInt) {
847 			conn->if_marker = (IFMarkInt - conn->if_marker);
848 		} else {
849 			login_ifmarker_count = (conn->if_marker / IFMarkInt);
850 			next_marker = (IFMarkInt * (login_ifmarker_count + 1)) +
851 					(login_ifmarker_count * MARKER_SIZE);
852 			conn->if_marker = (next_marker - conn->if_marker);
853 		}
854 		pr_debug("Setting IFMarker value to %u based on Initial"
855 			" Markerless Interval.\n", conn->if_marker);
856 	}
857 
858 	return 0;
859 }
860 
861 struct iscsi_conn *iscsit_get_conn_from_cid(struct iscsi_session *sess, u16 cid)
862 {
863 	struct iscsi_conn *conn;
864 
865 	spin_lock_bh(&sess->conn_lock);
866 	list_for_each_entry(conn, &sess->sess_conn_list, conn_list) {
867 		if ((conn->cid == cid) &&
868 		    (conn->conn_state == TARG_CONN_STATE_LOGGED_IN)) {
869 			iscsit_inc_conn_usage_count(conn);
870 			spin_unlock_bh(&sess->conn_lock);
871 			return conn;
872 		}
873 	}
874 	spin_unlock_bh(&sess->conn_lock);
875 
876 	return NULL;
877 }
878 
879 struct iscsi_conn *iscsit_get_conn_from_cid_rcfr(struct iscsi_session *sess, u16 cid)
880 {
881 	struct iscsi_conn *conn;
882 
883 	spin_lock_bh(&sess->conn_lock);
884 	list_for_each_entry(conn, &sess->sess_conn_list, conn_list) {
885 		if (conn->cid == cid) {
886 			iscsit_inc_conn_usage_count(conn);
887 			spin_lock(&conn->state_lock);
888 			atomic_set(&conn->connection_wait_rcfr, 1);
889 			spin_unlock(&conn->state_lock);
890 			spin_unlock_bh(&sess->conn_lock);
891 			return conn;
892 		}
893 	}
894 	spin_unlock_bh(&sess->conn_lock);
895 
896 	return NULL;
897 }
898 
899 void iscsit_check_conn_usage_count(struct iscsi_conn *conn)
900 {
901 	spin_lock_bh(&conn->conn_usage_lock);
902 	if (conn->conn_usage_count != 0) {
903 		conn->conn_waiting_on_uc = 1;
904 		spin_unlock_bh(&conn->conn_usage_lock);
905 
906 		wait_for_completion(&conn->conn_waiting_on_uc_comp);
907 		return;
908 	}
909 	spin_unlock_bh(&conn->conn_usage_lock);
910 }
911 
912 void iscsit_dec_conn_usage_count(struct iscsi_conn *conn)
913 {
914 	spin_lock_bh(&conn->conn_usage_lock);
915 	conn->conn_usage_count--;
916 
917 	if (!conn->conn_usage_count && conn->conn_waiting_on_uc)
918 		complete(&conn->conn_waiting_on_uc_comp);
919 
920 	spin_unlock_bh(&conn->conn_usage_lock);
921 }
922 
923 void iscsit_inc_conn_usage_count(struct iscsi_conn *conn)
924 {
925 	spin_lock_bh(&conn->conn_usage_lock);
926 	conn->conn_usage_count++;
927 	spin_unlock_bh(&conn->conn_usage_lock);
928 }
929 
930 static int iscsit_add_nopin(struct iscsi_conn *conn, int want_response)
931 {
932 	u8 state;
933 	struct iscsi_cmd *cmd;
934 
935 	cmd = iscsit_allocate_cmd(conn, TASK_RUNNING);
936 	if (!cmd)
937 		return -1;
938 
939 	cmd->iscsi_opcode = ISCSI_OP_NOOP_IN;
940 	state = (want_response) ? ISTATE_SEND_NOPIN_WANT_RESPONSE :
941 				ISTATE_SEND_NOPIN_NO_RESPONSE;
942 	cmd->init_task_tag = RESERVED_ITT;
943 	cmd->targ_xfer_tag = (want_response) ?
944 			     session_get_next_ttt(conn->sess) : 0xFFFFFFFF;
945 	spin_lock_bh(&conn->cmd_lock);
946 	list_add_tail(&cmd->i_conn_node, &conn->conn_cmd_list);
947 	spin_unlock_bh(&conn->cmd_lock);
948 
949 	if (want_response)
950 		iscsit_start_nopin_response_timer(conn);
951 	iscsit_add_cmd_to_immediate_queue(cmd, conn, state);
952 
953 	return 0;
954 }
955 
956 static void iscsit_handle_nopin_response_timeout(unsigned long data)
957 {
958 	struct iscsi_conn *conn = (struct iscsi_conn *) data;
959 
960 	iscsit_inc_conn_usage_count(conn);
961 
962 	spin_lock_bh(&conn->nopin_timer_lock);
963 	if (conn->nopin_response_timer_flags & ISCSI_TF_STOP) {
964 		spin_unlock_bh(&conn->nopin_timer_lock);
965 		iscsit_dec_conn_usage_count(conn);
966 		return;
967 	}
968 
969 	pr_debug("Did not receive response to NOPIN on CID: %hu on"
970 		" SID: %u, failing connection.\n", conn->cid,
971 			conn->sess->sid);
972 	conn->nopin_response_timer_flags &= ~ISCSI_TF_RUNNING;
973 	spin_unlock_bh(&conn->nopin_timer_lock);
974 
975 	{
976 	struct iscsi_portal_group *tpg = conn->sess->tpg;
977 	struct iscsi_tiqn *tiqn = tpg->tpg_tiqn;
978 
979 	if (tiqn) {
980 		spin_lock_bh(&tiqn->sess_err_stats.lock);
981 		strcpy(tiqn->sess_err_stats.last_sess_fail_rem_name,
982 				conn->sess->sess_ops->InitiatorName);
983 		tiqn->sess_err_stats.last_sess_failure_type =
984 				ISCSI_SESS_ERR_CXN_TIMEOUT;
985 		tiqn->sess_err_stats.cxn_timeout_errors++;
986 		atomic_long_inc(&conn->sess->conn_timeout_errors);
987 		spin_unlock_bh(&tiqn->sess_err_stats.lock);
988 	}
989 	}
990 
991 	iscsit_cause_connection_reinstatement(conn, 0);
992 	iscsit_dec_conn_usage_count(conn);
993 }
994 
995 void iscsit_mod_nopin_response_timer(struct iscsi_conn *conn)
996 {
997 	struct iscsi_session *sess = conn->sess;
998 	struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
999 
1000 	spin_lock_bh(&conn->nopin_timer_lock);
1001 	if (!(conn->nopin_response_timer_flags & ISCSI_TF_RUNNING)) {
1002 		spin_unlock_bh(&conn->nopin_timer_lock);
1003 		return;
1004 	}
1005 
1006 	mod_timer(&conn->nopin_response_timer,
1007 		(get_jiffies_64() + na->nopin_response_timeout * HZ));
1008 	spin_unlock_bh(&conn->nopin_timer_lock);
1009 }
1010 
1011 /*
1012  *	Called with conn->nopin_timer_lock held.
1013  */
1014 void iscsit_start_nopin_response_timer(struct iscsi_conn *conn)
1015 {
1016 	struct iscsi_session *sess = conn->sess;
1017 	struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
1018 
1019 	spin_lock_bh(&conn->nopin_timer_lock);
1020 	if (conn->nopin_response_timer_flags & ISCSI_TF_RUNNING) {
1021 		spin_unlock_bh(&conn->nopin_timer_lock);
1022 		return;
1023 	}
1024 
1025 	init_timer(&conn->nopin_response_timer);
1026 	conn->nopin_response_timer.expires =
1027 		(get_jiffies_64() + na->nopin_response_timeout * HZ);
1028 	conn->nopin_response_timer.data = (unsigned long)conn;
1029 	conn->nopin_response_timer.function = iscsit_handle_nopin_response_timeout;
1030 	conn->nopin_response_timer_flags &= ~ISCSI_TF_STOP;
1031 	conn->nopin_response_timer_flags |= ISCSI_TF_RUNNING;
1032 	add_timer(&conn->nopin_response_timer);
1033 
1034 	pr_debug("Started NOPIN Response Timer on CID: %d to %u"
1035 		" seconds\n", conn->cid, na->nopin_response_timeout);
1036 	spin_unlock_bh(&conn->nopin_timer_lock);
1037 }
1038 
1039 void iscsit_stop_nopin_response_timer(struct iscsi_conn *conn)
1040 {
1041 	spin_lock_bh(&conn->nopin_timer_lock);
1042 	if (!(conn->nopin_response_timer_flags & ISCSI_TF_RUNNING)) {
1043 		spin_unlock_bh(&conn->nopin_timer_lock);
1044 		return;
1045 	}
1046 	conn->nopin_response_timer_flags |= ISCSI_TF_STOP;
1047 	spin_unlock_bh(&conn->nopin_timer_lock);
1048 
1049 	del_timer_sync(&conn->nopin_response_timer);
1050 
1051 	spin_lock_bh(&conn->nopin_timer_lock);
1052 	conn->nopin_response_timer_flags &= ~ISCSI_TF_RUNNING;
1053 	spin_unlock_bh(&conn->nopin_timer_lock);
1054 }
1055 
1056 static void iscsit_handle_nopin_timeout(unsigned long data)
1057 {
1058 	struct iscsi_conn *conn = (struct iscsi_conn *) data;
1059 
1060 	iscsit_inc_conn_usage_count(conn);
1061 
1062 	spin_lock_bh(&conn->nopin_timer_lock);
1063 	if (conn->nopin_timer_flags & ISCSI_TF_STOP) {
1064 		spin_unlock_bh(&conn->nopin_timer_lock);
1065 		iscsit_dec_conn_usage_count(conn);
1066 		return;
1067 	}
1068 	conn->nopin_timer_flags &= ~ISCSI_TF_RUNNING;
1069 	spin_unlock_bh(&conn->nopin_timer_lock);
1070 
1071 	iscsit_add_nopin(conn, 1);
1072 	iscsit_dec_conn_usage_count(conn);
1073 }
1074 
1075 /*
1076  * Called with conn->nopin_timer_lock held.
1077  */
1078 void __iscsit_start_nopin_timer(struct iscsi_conn *conn)
1079 {
1080 	struct iscsi_session *sess = conn->sess;
1081 	struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
1082 	/*
1083 	* NOPIN timeout is disabled.
1084 	 */
1085 	if (!na->nopin_timeout)
1086 		return;
1087 
1088 	if (conn->nopin_timer_flags & ISCSI_TF_RUNNING)
1089 		return;
1090 
1091 	init_timer(&conn->nopin_timer);
1092 	conn->nopin_timer.expires = (get_jiffies_64() + na->nopin_timeout * HZ);
1093 	conn->nopin_timer.data = (unsigned long)conn;
1094 	conn->nopin_timer.function = iscsit_handle_nopin_timeout;
1095 	conn->nopin_timer_flags &= ~ISCSI_TF_STOP;
1096 	conn->nopin_timer_flags |= ISCSI_TF_RUNNING;
1097 	add_timer(&conn->nopin_timer);
1098 
1099 	pr_debug("Started NOPIN Timer on CID: %d at %u second"
1100 		" interval\n", conn->cid, na->nopin_timeout);
1101 }
1102 
1103 void iscsit_start_nopin_timer(struct iscsi_conn *conn)
1104 {
1105 	struct iscsi_session *sess = conn->sess;
1106 	struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
1107 	/*
1108 	 * NOPIN timeout is disabled..
1109 	 */
1110 	if (!na->nopin_timeout)
1111 		return;
1112 
1113 	spin_lock_bh(&conn->nopin_timer_lock);
1114 	if (conn->nopin_timer_flags & ISCSI_TF_RUNNING) {
1115 		spin_unlock_bh(&conn->nopin_timer_lock);
1116 		return;
1117 	}
1118 
1119 	init_timer(&conn->nopin_timer);
1120 	conn->nopin_timer.expires = (get_jiffies_64() + na->nopin_timeout * HZ);
1121 	conn->nopin_timer.data = (unsigned long)conn;
1122 	conn->nopin_timer.function = iscsit_handle_nopin_timeout;
1123 	conn->nopin_timer_flags &= ~ISCSI_TF_STOP;
1124 	conn->nopin_timer_flags |= ISCSI_TF_RUNNING;
1125 	add_timer(&conn->nopin_timer);
1126 
1127 	pr_debug("Started NOPIN Timer on CID: %d at %u second"
1128 			" interval\n", conn->cid, na->nopin_timeout);
1129 	spin_unlock_bh(&conn->nopin_timer_lock);
1130 }
1131 
1132 void iscsit_stop_nopin_timer(struct iscsi_conn *conn)
1133 {
1134 	spin_lock_bh(&conn->nopin_timer_lock);
1135 	if (!(conn->nopin_timer_flags & ISCSI_TF_RUNNING)) {
1136 		spin_unlock_bh(&conn->nopin_timer_lock);
1137 		return;
1138 	}
1139 	conn->nopin_timer_flags |= ISCSI_TF_STOP;
1140 	spin_unlock_bh(&conn->nopin_timer_lock);
1141 
1142 	del_timer_sync(&conn->nopin_timer);
1143 
1144 	spin_lock_bh(&conn->nopin_timer_lock);
1145 	conn->nopin_timer_flags &= ~ISCSI_TF_RUNNING;
1146 	spin_unlock_bh(&conn->nopin_timer_lock);
1147 }
1148 
1149 int iscsit_send_tx_data(
1150 	struct iscsi_cmd *cmd,
1151 	struct iscsi_conn *conn,
1152 	int use_misc)
1153 {
1154 	int tx_sent, tx_size;
1155 	u32 iov_count;
1156 	struct kvec *iov;
1157 
1158 send_data:
1159 	tx_size = cmd->tx_size;
1160 
1161 	if (!use_misc) {
1162 		iov = &cmd->iov_data[0];
1163 		iov_count = cmd->iov_data_count;
1164 	} else {
1165 		iov = &cmd->iov_misc[0];
1166 		iov_count = cmd->iov_misc_count;
1167 	}
1168 
1169 	tx_sent = tx_data(conn, &iov[0], iov_count, tx_size);
1170 	if (tx_size != tx_sent) {
1171 		if (tx_sent == -EAGAIN) {
1172 			pr_err("tx_data() returned -EAGAIN\n");
1173 			goto send_data;
1174 		} else
1175 			return -1;
1176 	}
1177 	cmd->tx_size = 0;
1178 
1179 	return 0;
1180 }
1181 
1182 int iscsit_fe_sendpage_sg(
1183 	struct iscsi_cmd *cmd,
1184 	struct iscsi_conn *conn)
1185 {
1186 	struct scatterlist *sg = cmd->first_data_sg;
1187 	struct kvec iov;
1188 	u32 tx_hdr_size, data_len;
1189 	u32 offset = cmd->first_data_sg_off;
1190 	int tx_sent, iov_off;
1191 
1192 send_hdr:
1193 	tx_hdr_size = ISCSI_HDR_LEN;
1194 	if (conn->conn_ops->HeaderDigest)
1195 		tx_hdr_size += ISCSI_CRC_LEN;
1196 
1197 	iov.iov_base = cmd->pdu;
1198 	iov.iov_len = tx_hdr_size;
1199 
1200 	tx_sent = tx_data(conn, &iov, 1, tx_hdr_size);
1201 	if (tx_hdr_size != tx_sent) {
1202 		if (tx_sent == -EAGAIN) {
1203 			pr_err("tx_data() returned -EAGAIN\n");
1204 			goto send_hdr;
1205 		}
1206 		return -1;
1207 	}
1208 
1209 	data_len = cmd->tx_size - tx_hdr_size - cmd->padding;
1210 	/*
1211 	 * Set iov_off used by padding and data digest tx_data() calls below
1212 	 * in order to determine proper offset into cmd->iov_data[]
1213 	 */
1214 	if (conn->conn_ops->DataDigest) {
1215 		data_len -= ISCSI_CRC_LEN;
1216 		if (cmd->padding)
1217 			iov_off = (cmd->iov_data_count - 2);
1218 		else
1219 			iov_off = (cmd->iov_data_count - 1);
1220 	} else {
1221 		iov_off = (cmd->iov_data_count - 1);
1222 	}
1223 	/*
1224 	 * Perform sendpage() for each page in the scatterlist
1225 	 */
1226 	while (data_len) {
1227 		u32 space = (sg->length - offset);
1228 		u32 sub_len = min_t(u32, data_len, space);
1229 send_pg:
1230 		tx_sent = conn->sock->ops->sendpage(conn->sock,
1231 					sg_page(sg), sg->offset + offset, sub_len, 0);
1232 		if (tx_sent != sub_len) {
1233 			if (tx_sent == -EAGAIN) {
1234 				pr_err("tcp_sendpage() returned"
1235 						" -EAGAIN\n");
1236 				goto send_pg;
1237 			}
1238 
1239 			pr_err("tcp_sendpage() failure: %d\n",
1240 					tx_sent);
1241 			return -1;
1242 		}
1243 
1244 		data_len -= sub_len;
1245 		offset = 0;
1246 		sg = sg_next(sg);
1247 	}
1248 
1249 send_padding:
1250 	if (cmd->padding) {
1251 		struct kvec *iov_p = &cmd->iov_data[iov_off++];
1252 
1253 		tx_sent = tx_data(conn, iov_p, 1, cmd->padding);
1254 		if (cmd->padding != tx_sent) {
1255 			if (tx_sent == -EAGAIN) {
1256 				pr_err("tx_data() returned -EAGAIN\n");
1257 				goto send_padding;
1258 			}
1259 			return -1;
1260 		}
1261 	}
1262 
1263 send_datacrc:
1264 	if (conn->conn_ops->DataDigest) {
1265 		struct kvec *iov_d = &cmd->iov_data[iov_off];
1266 
1267 		tx_sent = tx_data(conn, iov_d, 1, ISCSI_CRC_LEN);
1268 		if (ISCSI_CRC_LEN != tx_sent) {
1269 			if (tx_sent == -EAGAIN) {
1270 				pr_err("tx_data() returned -EAGAIN\n");
1271 				goto send_datacrc;
1272 			}
1273 			return -1;
1274 		}
1275 	}
1276 
1277 	return 0;
1278 }
1279 
1280 /*
1281  *      This function is used for mainly sending a ISCSI_TARG_LOGIN_RSP PDU
1282  *      back to the Initiator when an expection condition occurs with the
1283  *      errors set in status_class and status_detail.
1284  *
1285  *      Parameters:     iSCSI Connection, Status Class, Status Detail.
1286  *      Returns:        0 on success, -1 on error.
1287  */
1288 int iscsit_tx_login_rsp(struct iscsi_conn *conn, u8 status_class, u8 status_detail)
1289 {
1290 	struct iscsi_login_rsp *hdr;
1291 	struct iscsi_login *login = conn->conn_login;
1292 
1293 	login->login_failed = 1;
1294 	iscsit_collect_login_stats(conn, status_class, status_detail);
1295 
1296 	memset(&login->rsp[0], 0, ISCSI_HDR_LEN);
1297 
1298 	hdr	= (struct iscsi_login_rsp *)&login->rsp[0];
1299 	hdr->opcode		= ISCSI_OP_LOGIN_RSP;
1300 	hdr->status_class	= status_class;
1301 	hdr->status_detail	= status_detail;
1302 	hdr->itt		= conn->login_itt;
1303 
1304 	return conn->conn_transport->iscsit_put_login_tx(conn, login, 0);
1305 }
1306 
1307 void iscsit_print_session_params(struct iscsi_session *sess)
1308 {
1309 	struct iscsi_conn *conn;
1310 
1311 	pr_debug("-----------------------------[Session Params for"
1312 		" SID: %u]-----------------------------\n", sess->sid);
1313 	spin_lock_bh(&sess->conn_lock);
1314 	list_for_each_entry(conn, &sess->sess_conn_list, conn_list)
1315 		iscsi_dump_conn_ops(conn->conn_ops);
1316 	spin_unlock_bh(&sess->conn_lock);
1317 
1318 	iscsi_dump_sess_ops(sess->sess_ops);
1319 }
1320 
1321 static int iscsit_do_rx_data(
1322 	struct iscsi_conn *conn,
1323 	struct iscsi_data_count *count)
1324 {
1325 	int data = count->data_length, rx_loop = 0, total_rx = 0;
1326 	struct msghdr msg;
1327 
1328 	if (!conn || !conn->sock || !conn->conn_ops)
1329 		return -1;
1330 
1331 	memset(&msg, 0, sizeof(struct msghdr));
1332 	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC,
1333 		      count->iov, count->iov_count, data);
1334 
1335 	while (total_rx < data) {
1336 		rx_loop = sock_recvmsg(conn->sock, &msg,
1337 				      (data - total_rx), MSG_WAITALL);
1338 		if (rx_loop <= 0) {
1339 			pr_debug("rx_loop: %d total_rx: %d\n",
1340 				rx_loop, total_rx);
1341 			return rx_loop;
1342 		}
1343 		total_rx += rx_loop;
1344 		pr_debug("rx_loop: %d, total_rx: %d, data: %d\n",
1345 				rx_loop, total_rx, data);
1346 	}
1347 
1348 	return total_rx;
1349 }
1350 
1351 static int iscsit_do_tx_data(
1352 	struct iscsi_conn *conn,
1353 	struct iscsi_data_count *count)
1354 {
1355 	int ret, iov_len;
1356 	struct kvec *iov_p;
1357 	struct msghdr msg;
1358 
1359 	if (!conn || !conn->sock || !conn->conn_ops)
1360 		return -1;
1361 
1362 	if (count->data_length <= 0) {
1363 		pr_err("Data length is: %d\n", count->data_length);
1364 		return -1;
1365 	}
1366 
1367 	memset(&msg, 0, sizeof(struct msghdr));
1368 
1369 	iov_p = count->iov;
1370 	iov_len = count->iov_count;
1371 
1372 	ret = kernel_sendmsg(conn->sock, &msg, iov_p, iov_len,
1373 			     count->data_length);
1374 	if (ret != count->data_length) {
1375 		pr_err("Unexpected ret: %d send data %d\n",
1376 		       ret, count->data_length);
1377 		return -EPIPE;
1378 	}
1379 	pr_debug("ret: %d, sent data: %d\n", ret, count->data_length);
1380 
1381 	return ret;
1382 }
1383 
1384 int rx_data(
1385 	struct iscsi_conn *conn,
1386 	struct kvec *iov,
1387 	int iov_count,
1388 	int data)
1389 {
1390 	struct iscsi_data_count c;
1391 
1392 	if (!conn || !conn->sock || !conn->conn_ops)
1393 		return -1;
1394 
1395 	memset(&c, 0, sizeof(struct iscsi_data_count));
1396 	c.iov = iov;
1397 	c.iov_count = iov_count;
1398 	c.data_length = data;
1399 	c.type = ISCSI_RX_DATA;
1400 
1401 	return iscsit_do_rx_data(conn, &c);
1402 }
1403 
1404 int tx_data(
1405 	struct iscsi_conn *conn,
1406 	struct kvec *iov,
1407 	int iov_count,
1408 	int data)
1409 {
1410 	struct iscsi_data_count c;
1411 
1412 	if (!conn || !conn->sock || !conn->conn_ops)
1413 		return -1;
1414 
1415 	memset(&c, 0, sizeof(struct iscsi_data_count));
1416 	c.iov = iov;
1417 	c.iov_count = iov_count;
1418 	c.data_length = data;
1419 	c.type = ISCSI_TX_DATA;
1420 
1421 	return iscsit_do_tx_data(conn, &c);
1422 }
1423 
1424 void iscsit_collect_login_stats(
1425 	struct iscsi_conn *conn,
1426 	u8 status_class,
1427 	u8 status_detail)
1428 {
1429 	struct iscsi_param *intrname = NULL;
1430 	struct iscsi_tiqn *tiqn;
1431 	struct iscsi_login_stats *ls;
1432 
1433 	tiqn = iscsit_snmp_get_tiqn(conn);
1434 	if (!tiqn)
1435 		return;
1436 
1437 	ls = &tiqn->login_stats;
1438 
1439 	spin_lock(&ls->lock);
1440 	if (!strcmp(conn->login_ip, ls->last_intr_fail_ip_addr) &&
1441 	    ((get_jiffies_64() - ls->last_fail_time) < 10)) {
1442 		/* We already have the failure info for this login */
1443 		spin_unlock(&ls->lock);
1444 		return;
1445 	}
1446 
1447 	if (status_class == ISCSI_STATUS_CLS_SUCCESS)
1448 		ls->accepts++;
1449 	else if (status_class == ISCSI_STATUS_CLS_REDIRECT) {
1450 		ls->redirects++;
1451 		ls->last_fail_type = ISCSI_LOGIN_FAIL_REDIRECT;
1452 	} else if ((status_class == ISCSI_STATUS_CLS_INITIATOR_ERR)  &&
1453 		 (status_detail == ISCSI_LOGIN_STATUS_AUTH_FAILED)) {
1454 		ls->authenticate_fails++;
1455 		ls->last_fail_type =  ISCSI_LOGIN_FAIL_AUTHENTICATE;
1456 	} else if ((status_class == ISCSI_STATUS_CLS_INITIATOR_ERR)  &&
1457 		 (status_detail == ISCSI_LOGIN_STATUS_TGT_FORBIDDEN)) {
1458 		ls->authorize_fails++;
1459 		ls->last_fail_type = ISCSI_LOGIN_FAIL_AUTHORIZE;
1460 	} else if ((status_class == ISCSI_STATUS_CLS_INITIATOR_ERR) &&
1461 		 (status_detail == ISCSI_LOGIN_STATUS_INIT_ERR)) {
1462 		ls->negotiate_fails++;
1463 		ls->last_fail_type = ISCSI_LOGIN_FAIL_NEGOTIATE;
1464 	} else {
1465 		ls->other_fails++;
1466 		ls->last_fail_type = ISCSI_LOGIN_FAIL_OTHER;
1467 	}
1468 
1469 	/* Save initiator name, ip address and time, if it is a failed login */
1470 	if (status_class != ISCSI_STATUS_CLS_SUCCESS) {
1471 		if (conn->param_list)
1472 			intrname = iscsi_find_param_from_key(INITIATORNAME,
1473 							     conn->param_list);
1474 		strlcpy(ls->last_intr_fail_name,
1475 		       (intrname ? intrname->value : "Unknown"),
1476 		       sizeof(ls->last_intr_fail_name));
1477 
1478 		ls->last_intr_fail_ip_family = conn->login_family;
1479 
1480 		snprintf(ls->last_intr_fail_ip_addr, IPV6_ADDRESS_SPACE,
1481 				"%s", conn->login_ip);
1482 		ls->last_fail_time = get_jiffies_64();
1483 	}
1484 
1485 	spin_unlock(&ls->lock);
1486 }
1487 
1488 struct iscsi_tiqn *iscsit_snmp_get_tiqn(struct iscsi_conn *conn)
1489 {
1490 	struct iscsi_portal_group *tpg;
1491 
1492 	if (!conn || !conn->sess)
1493 		return NULL;
1494 
1495 	tpg = conn->sess->tpg;
1496 	if (!tpg)
1497 		return NULL;
1498 
1499 	if (!tpg->tpg_tiqn)
1500 		return NULL;
1501 
1502 	return tpg->tpg_tiqn;
1503 }
1504