xref: /linux/drivers/target/iscsi/iscsi_target_erl0.c (revision e0bf6c5ca2d3281f231c5f0c9bf145e9513644de)
1 /******************************************************************************
2  * This file contains error recovery level zero functions used by
3  * the iSCSI Target driver.
4  *
5  * (c) Copyright 2007-2013 Datera, Inc.
6  *
7  * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  ******************************************************************************/
19 
20 #include <scsi/iscsi_proto.h>
21 #include <target/target_core_base.h>
22 #include <target/target_core_fabric.h>
23 
24 #include <target/iscsi/iscsi_target_core.h>
25 #include "iscsi_target_seq_pdu_list.h"
26 #include "iscsi_target_tq.h"
27 #include "iscsi_target_erl0.h"
28 #include "iscsi_target_erl1.h"
29 #include "iscsi_target_erl2.h"
30 #include "iscsi_target_util.h"
31 #include "iscsi_target.h"
32 
33 /*
34  *	Used to set values in struct iscsi_cmd that iscsit_dataout_check_sequence()
35  *	checks against to determine a PDU's Offset+Length is within the current
36  *	DataOUT Sequence.  Used for DataSequenceInOrder=Yes only.
37  */
38 void iscsit_set_dataout_sequence_values(
39 	struct iscsi_cmd *cmd)
40 {
41 	struct iscsi_conn *conn = cmd->conn;
42 	/*
43 	 * Still set seq_start_offset and seq_end_offset for Unsolicited
44 	 * DataOUT, even if DataSequenceInOrder=No.
45 	 */
46 	if (cmd->unsolicited_data) {
47 		cmd->seq_start_offset = cmd->write_data_done;
48 		cmd->seq_end_offset = (cmd->write_data_done +
49 			((cmd->se_cmd.data_length >
50 			  conn->sess->sess_ops->FirstBurstLength) ?
51 			 conn->sess->sess_ops->FirstBurstLength : cmd->se_cmd.data_length));
52 		return;
53 	}
54 
55 	if (!conn->sess->sess_ops->DataSequenceInOrder)
56 		return;
57 
58 	if (!cmd->seq_start_offset && !cmd->seq_end_offset) {
59 		cmd->seq_start_offset = cmd->write_data_done;
60 		cmd->seq_end_offset = (cmd->se_cmd.data_length >
61 			conn->sess->sess_ops->MaxBurstLength) ?
62 			(cmd->write_data_done +
63 			conn->sess->sess_ops->MaxBurstLength) : cmd->se_cmd.data_length;
64 	} else {
65 		cmd->seq_start_offset = cmd->seq_end_offset;
66 		cmd->seq_end_offset = ((cmd->seq_end_offset +
67 			conn->sess->sess_ops->MaxBurstLength) >=
68 			cmd->se_cmd.data_length) ? cmd->se_cmd.data_length :
69 			(cmd->seq_end_offset +
70 			 conn->sess->sess_ops->MaxBurstLength);
71 	}
72 }
73 
74 static int iscsit_dataout_within_command_recovery_check(
75 	struct iscsi_cmd *cmd,
76 	unsigned char *buf)
77 {
78 	struct iscsi_conn *conn = cmd->conn;
79 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
80 	u32 payload_length = ntoh24(hdr->dlength);
81 
82 	/*
83 	 * We do the within-command recovery checks here as it is
84 	 * the first function called in iscsi_check_pre_dataout().
85 	 * Basically, if we are in within-command recovery and
86 	 * the PDU does not contain the offset the sequence needs,
87 	 * dump the payload.
88 	 *
89 	 * This only applies to DataPDUInOrder=Yes, for
90 	 * DataPDUInOrder=No we only re-request the failed PDU
91 	 * and check that all PDUs in a sequence are received
92 	 * upon end of sequence.
93 	 */
94 	if (conn->sess->sess_ops->DataSequenceInOrder) {
95 		if ((cmd->cmd_flags & ICF_WITHIN_COMMAND_RECOVERY) &&
96 		    cmd->write_data_done != be32_to_cpu(hdr->offset))
97 			goto dump;
98 
99 		cmd->cmd_flags &= ~ICF_WITHIN_COMMAND_RECOVERY;
100 	} else {
101 		struct iscsi_seq *seq;
102 
103 		seq = iscsit_get_seq_holder(cmd, be32_to_cpu(hdr->offset),
104 					    payload_length);
105 		if (!seq)
106 			return DATAOUT_CANNOT_RECOVER;
107 		/*
108 		 * Set the struct iscsi_seq pointer to reuse later.
109 		 */
110 		cmd->seq_ptr = seq;
111 
112 		if (conn->sess->sess_ops->DataPDUInOrder) {
113 			if (seq->status ==
114 			    DATAOUT_SEQUENCE_WITHIN_COMMAND_RECOVERY &&
115 			   (seq->offset != be32_to_cpu(hdr->offset) ||
116 			    seq->data_sn != be32_to_cpu(hdr->datasn)))
117 				goto dump;
118 		} else {
119 			if (seq->status ==
120 			     DATAOUT_SEQUENCE_WITHIN_COMMAND_RECOVERY &&
121 			    seq->data_sn != be32_to_cpu(hdr->datasn))
122 				goto dump;
123 		}
124 
125 		if (seq->status == DATAOUT_SEQUENCE_COMPLETE)
126 			goto dump;
127 
128 		if (seq->status != DATAOUT_SEQUENCE_COMPLETE)
129 			seq->status = 0;
130 	}
131 
132 	return DATAOUT_NORMAL;
133 
134 dump:
135 	pr_err("Dumping DataOUT PDU Offset: %u Length: %d DataSN:"
136 		" 0x%08x\n", hdr->offset, payload_length, hdr->datasn);
137 	return iscsit_dump_data_payload(conn, payload_length, 1);
138 }
139 
140 static int iscsit_dataout_check_unsolicited_sequence(
141 	struct iscsi_cmd *cmd,
142 	unsigned char *buf)
143 {
144 	u32 first_burst_len;
145 	struct iscsi_conn *conn = cmd->conn;
146 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
147 	u32 payload_length = ntoh24(hdr->dlength);
148 
149 
150 	if ((be32_to_cpu(hdr->offset) < cmd->seq_start_offset) ||
151 	   ((be32_to_cpu(hdr->offset) + payload_length) > cmd->seq_end_offset)) {
152 		pr_err("Command ITT: 0x%08x with Offset: %u,"
153 		" Length: %u outside of Unsolicited Sequence %u:%u while"
154 		" DataSequenceInOrder=Yes.\n", cmd->init_task_tag,
155 		be32_to_cpu(hdr->offset), payload_length, cmd->seq_start_offset,
156 			cmd->seq_end_offset);
157 		return DATAOUT_CANNOT_RECOVER;
158 	}
159 
160 	first_burst_len = (cmd->first_burst_len + payload_length);
161 
162 	if (first_burst_len > conn->sess->sess_ops->FirstBurstLength) {
163 		pr_err("Total %u bytes exceeds FirstBurstLength: %u"
164 			" for this Unsolicited DataOut Burst.\n",
165 			first_burst_len, conn->sess->sess_ops->FirstBurstLength);
166 		transport_send_check_condition_and_sense(&cmd->se_cmd,
167 				TCM_INCORRECT_AMOUNT_OF_DATA, 0);
168 		return DATAOUT_CANNOT_RECOVER;
169 	}
170 
171 	/*
172 	 * Perform various MaxBurstLength and ISCSI_FLAG_CMD_FINAL sanity
173 	 * checks for the current Unsolicited DataOUT Sequence.
174 	 */
175 	if (hdr->flags & ISCSI_FLAG_CMD_FINAL) {
176 		/*
177 		 * Ignore ISCSI_FLAG_CMD_FINAL checks while DataPDUInOrder=No, end of
178 		 * sequence checks are handled in
179 		 * iscsit_dataout_datapduinorder_no_fbit().
180 		 */
181 		if (!conn->sess->sess_ops->DataPDUInOrder)
182 			goto out;
183 
184 		if ((first_burst_len != cmd->se_cmd.data_length) &&
185 		    (first_burst_len != conn->sess->sess_ops->FirstBurstLength)) {
186 			pr_err("Unsolicited non-immediate data"
187 			" received %u does not equal FirstBurstLength: %u, and"
188 			" does not equal ExpXferLen %u.\n", first_burst_len,
189 				conn->sess->sess_ops->FirstBurstLength,
190 				cmd->se_cmd.data_length);
191 			transport_send_check_condition_and_sense(&cmd->se_cmd,
192 					TCM_INCORRECT_AMOUNT_OF_DATA, 0);
193 			return DATAOUT_CANNOT_RECOVER;
194 		}
195 	} else {
196 		if (first_burst_len == conn->sess->sess_ops->FirstBurstLength) {
197 			pr_err("Command ITT: 0x%08x reached"
198 			" FirstBurstLength: %u, but ISCSI_FLAG_CMD_FINAL is not set. protocol"
199 				" error.\n", cmd->init_task_tag,
200 				conn->sess->sess_ops->FirstBurstLength);
201 			return DATAOUT_CANNOT_RECOVER;
202 		}
203 		if (first_burst_len == cmd->se_cmd.data_length) {
204 			pr_err("Command ITT: 0x%08x reached"
205 			" ExpXferLen: %u, but ISCSI_FLAG_CMD_FINAL is not set. protocol"
206 			" error.\n", cmd->init_task_tag, cmd->se_cmd.data_length);
207 			return DATAOUT_CANNOT_RECOVER;
208 		}
209 	}
210 
211 out:
212 	return DATAOUT_NORMAL;
213 }
214 
215 static int iscsit_dataout_check_sequence(
216 	struct iscsi_cmd *cmd,
217 	unsigned char *buf)
218 {
219 	u32 next_burst_len;
220 	struct iscsi_conn *conn = cmd->conn;
221 	struct iscsi_seq *seq = NULL;
222 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
223 	u32 payload_length = ntoh24(hdr->dlength);
224 
225 	/*
226 	 * For DataSequenceInOrder=Yes: Check that the offset and offset+length
227 	 * is within range as defined by iscsi_set_dataout_sequence_values().
228 	 *
229 	 * For DataSequenceInOrder=No: Check that an struct iscsi_seq exists for
230 	 * offset+length tuple.
231 	 */
232 	if (conn->sess->sess_ops->DataSequenceInOrder) {
233 		/*
234 		 * Due to possibility of recovery DataOUT sent by the initiator
235 		 * fullfilling an Recovery R2T, it's best to just dump the
236 		 * payload here, instead of erroring out.
237 		 */
238 		if ((be32_to_cpu(hdr->offset) < cmd->seq_start_offset) ||
239 		   ((be32_to_cpu(hdr->offset) + payload_length) > cmd->seq_end_offset)) {
240 			pr_err("Command ITT: 0x%08x with Offset: %u,"
241 			" Length: %u outside of Sequence %u:%u while"
242 			" DataSequenceInOrder=Yes.\n", cmd->init_task_tag,
243 			be32_to_cpu(hdr->offset), payload_length, cmd->seq_start_offset,
244 				cmd->seq_end_offset);
245 
246 			if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
247 				return DATAOUT_CANNOT_RECOVER;
248 			return DATAOUT_WITHIN_COMMAND_RECOVERY;
249 		}
250 
251 		next_burst_len = (cmd->next_burst_len + payload_length);
252 	} else {
253 		seq = iscsit_get_seq_holder(cmd, be32_to_cpu(hdr->offset),
254 					    payload_length);
255 		if (!seq)
256 			return DATAOUT_CANNOT_RECOVER;
257 		/*
258 		 * Set the struct iscsi_seq pointer to reuse later.
259 		 */
260 		cmd->seq_ptr = seq;
261 
262 		if (seq->status == DATAOUT_SEQUENCE_COMPLETE) {
263 			if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
264 				return DATAOUT_CANNOT_RECOVER;
265 			return DATAOUT_WITHIN_COMMAND_RECOVERY;
266 		}
267 
268 		next_burst_len = (seq->next_burst_len + payload_length);
269 	}
270 
271 	if (next_burst_len > conn->sess->sess_ops->MaxBurstLength) {
272 		pr_err("Command ITT: 0x%08x, NextBurstLength: %u and"
273 			" Length: %u exceeds MaxBurstLength: %u. protocol"
274 			" error.\n", cmd->init_task_tag,
275 			(next_burst_len - payload_length),
276 			payload_length, conn->sess->sess_ops->MaxBurstLength);
277 		return DATAOUT_CANNOT_RECOVER;
278 	}
279 
280 	/*
281 	 * Perform various MaxBurstLength and ISCSI_FLAG_CMD_FINAL sanity
282 	 * checks for the current DataOUT Sequence.
283 	 */
284 	if (hdr->flags & ISCSI_FLAG_CMD_FINAL) {
285 		/*
286 		 * Ignore ISCSI_FLAG_CMD_FINAL checks while DataPDUInOrder=No, end of
287 		 * sequence checks are handled in
288 		 * iscsit_dataout_datapduinorder_no_fbit().
289 		 */
290 		if (!conn->sess->sess_ops->DataPDUInOrder)
291 			goto out;
292 
293 		if (conn->sess->sess_ops->DataSequenceInOrder) {
294 			if ((next_burst_len <
295 			     conn->sess->sess_ops->MaxBurstLength) &&
296 			   ((cmd->write_data_done + payload_length) <
297 			     cmd->se_cmd.data_length)) {
298 				pr_err("Command ITT: 0x%08x set ISCSI_FLAG_CMD_FINAL"
299 				" before end of DataOUT sequence, protocol"
300 				" error.\n", cmd->init_task_tag);
301 				return DATAOUT_CANNOT_RECOVER;
302 			}
303 		} else {
304 			if (next_burst_len < seq->xfer_len) {
305 				pr_err("Command ITT: 0x%08x set ISCSI_FLAG_CMD_FINAL"
306 				" before end of DataOUT sequence, protocol"
307 				" error.\n", cmd->init_task_tag);
308 				return DATAOUT_CANNOT_RECOVER;
309 			}
310 		}
311 	} else {
312 		if (conn->sess->sess_ops->DataSequenceInOrder) {
313 			if (next_burst_len ==
314 					conn->sess->sess_ops->MaxBurstLength) {
315 				pr_err("Command ITT: 0x%08x reached"
316 				" MaxBurstLength: %u, but ISCSI_FLAG_CMD_FINAL is"
317 				" not set, protocol error.", cmd->init_task_tag,
318 					conn->sess->sess_ops->MaxBurstLength);
319 				return DATAOUT_CANNOT_RECOVER;
320 			}
321 			if ((cmd->write_data_done + payload_length) ==
322 					cmd->se_cmd.data_length) {
323 				pr_err("Command ITT: 0x%08x reached"
324 				" last DataOUT PDU in sequence but ISCSI_FLAG_"
325 				"CMD_FINAL is not set, protocol error.\n",
326 					cmd->init_task_tag);
327 				return DATAOUT_CANNOT_RECOVER;
328 			}
329 		} else {
330 			if (next_burst_len == seq->xfer_len) {
331 				pr_err("Command ITT: 0x%08x reached"
332 				" last DataOUT PDU in sequence but ISCSI_FLAG_"
333 				"CMD_FINAL is not set, protocol error.\n",
334 					cmd->init_task_tag);
335 				return DATAOUT_CANNOT_RECOVER;
336 			}
337 		}
338 	}
339 
340 out:
341 	return DATAOUT_NORMAL;
342 }
343 
344 static int iscsit_dataout_check_datasn(
345 	struct iscsi_cmd *cmd,
346 	unsigned char *buf)
347 {
348 	u32 data_sn = 0;
349 	struct iscsi_conn *conn = cmd->conn;
350 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
351 	u32 payload_length = ntoh24(hdr->dlength);
352 
353 	/*
354 	 * Considering the target has no method of re-requesting DataOUT
355 	 * by DataSN, if we receieve a greater DataSN than expected we
356 	 * assume the functions for DataPDUInOrder=[Yes,No] below will
357 	 * handle it.
358 	 *
359 	 * If the DataSN is less than expected, dump the payload.
360 	 */
361 	if (conn->sess->sess_ops->DataSequenceInOrder)
362 		data_sn = cmd->data_sn;
363 	else {
364 		struct iscsi_seq *seq = cmd->seq_ptr;
365 		data_sn = seq->data_sn;
366 	}
367 
368 	if (be32_to_cpu(hdr->datasn) > data_sn) {
369 		pr_err("Command ITT: 0x%08x, received DataSN: 0x%08x"
370 			" higher than expected 0x%08x.\n", cmd->init_task_tag,
371 				be32_to_cpu(hdr->datasn), data_sn);
372 		goto recover;
373 	} else if (be32_to_cpu(hdr->datasn) < data_sn) {
374 		pr_err("Command ITT: 0x%08x, received DataSN: 0x%08x"
375 			" lower than expected 0x%08x, discarding payload.\n",
376 			cmd->init_task_tag, be32_to_cpu(hdr->datasn), data_sn);
377 		goto dump;
378 	}
379 
380 	return DATAOUT_NORMAL;
381 
382 recover:
383 	if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
384 		pr_err("Unable to perform within-command recovery"
385 				" while ERL=0.\n");
386 		return DATAOUT_CANNOT_RECOVER;
387 	}
388 dump:
389 	if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
390 		return DATAOUT_CANNOT_RECOVER;
391 
392 	return DATAOUT_WITHIN_COMMAND_RECOVERY;
393 }
394 
395 static int iscsit_dataout_pre_datapduinorder_yes(
396 	struct iscsi_cmd *cmd,
397 	unsigned char *buf)
398 {
399 	int dump = 0, recovery = 0;
400 	struct iscsi_conn *conn = cmd->conn;
401 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
402 	u32 payload_length = ntoh24(hdr->dlength);
403 
404 	/*
405 	 * For DataSequenceInOrder=Yes: If the offset is greater than the global
406 	 * DataPDUInOrder=Yes offset counter in struct iscsi_cmd a protcol error has
407 	 * occurred and fail the connection.
408 	 *
409 	 * For DataSequenceInOrder=No: If the offset is greater than the per
410 	 * sequence DataPDUInOrder=Yes offset counter in struct iscsi_seq a protocol
411 	 * error has occurred and fail the connection.
412 	 */
413 	if (conn->sess->sess_ops->DataSequenceInOrder) {
414 		if (be32_to_cpu(hdr->offset) != cmd->write_data_done) {
415 			pr_err("Command ITT: 0x%08x, received offset"
416 			" %u different than expected %u.\n", cmd->init_task_tag,
417 				be32_to_cpu(hdr->offset), cmd->write_data_done);
418 			recovery = 1;
419 			goto recover;
420 		}
421 	} else {
422 		struct iscsi_seq *seq = cmd->seq_ptr;
423 
424 		if (be32_to_cpu(hdr->offset) > seq->offset) {
425 			pr_err("Command ITT: 0x%08x, received offset"
426 			" %u greater than expected %u.\n", cmd->init_task_tag,
427 				be32_to_cpu(hdr->offset), seq->offset);
428 			recovery = 1;
429 			goto recover;
430 		} else if (be32_to_cpu(hdr->offset) < seq->offset) {
431 			pr_err("Command ITT: 0x%08x, received offset"
432 			" %u less than expected %u, discarding payload.\n",
433 				cmd->init_task_tag, be32_to_cpu(hdr->offset),
434 				seq->offset);
435 			dump = 1;
436 			goto dump;
437 		}
438 	}
439 
440 	return DATAOUT_NORMAL;
441 
442 recover:
443 	if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
444 		pr_err("Unable to perform within-command recovery"
445 				" while ERL=0.\n");
446 		return DATAOUT_CANNOT_RECOVER;
447 	}
448 dump:
449 	if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
450 		return DATAOUT_CANNOT_RECOVER;
451 
452 	return (recovery) ? iscsit_recover_dataout_sequence(cmd,
453 		be32_to_cpu(hdr->offset), payload_length) :
454 	       (dump) ? DATAOUT_WITHIN_COMMAND_RECOVERY : DATAOUT_NORMAL;
455 }
456 
457 static int iscsit_dataout_pre_datapduinorder_no(
458 	struct iscsi_cmd *cmd,
459 	unsigned char *buf)
460 {
461 	struct iscsi_pdu *pdu;
462 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
463 	u32 payload_length = ntoh24(hdr->dlength);
464 
465 	pdu = iscsit_get_pdu_holder(cmd, be32_to_cpu(hdr->offset),
466 				    payload_length);
467 	if (!pdu)
468 		return DATAOUT_CANNOT_RECOVER;
469 
470 	cmd->pdu_ptr = pdu;
471 
472 	switch (pdu->status) {
473 	case ISCSI_PDU_NOT_RECEIVED:
474 	case ISCSI_PDU_CRC_FAILED:
475 	case ISCSI_PDU_TIMED_OUT:
476 		break;
477 	case ISCSI_PDU_RECEIVED_OK:
478 		pr_err("Command ITT: 0x%08x received already gotten"
479 			" Offset: %u, Length: %u\n", cmd->init_task_tag,
480 				be32_to_cpu(hdr->offset), payload_length);
481 		return iscsit_dump_data_payload(cmd->conn, payload_length, 1);
482 	default:
483 		return DATAOUT_CANNOT_RECOVER;
484 	}
485 
486 	return DATAOUT_NORMAL;
487 }
488 
489 static int iscsit_dataout_update_r2t(struct iscsi_cmd *cmd, u32 offset, u32 length)
490 {
491 	struct iscsi_r2t *r2t;
492 
493 	if (cmd->unsolicited_data)
494 		return 0;
495 
496 	r2t = iscsit_get_r2t_for_eos(cmd, offset, length);
497 	if (!r2t)
498 		return -1;
499 
500 	spin_lock_bh(&cmd->r2t_lock);
501 	r2t->seq_complete = 1;
502 	cmd->outstanding_r2ts--;
503 	spin_unlock_bh(&cmd->r2t_lock);
504 
505 	return 0;
506 }
507 
508 static int iscsit_dataout_update_datapduinorder_no(
509 	struct iscsi_cmd *cmd,
510 	u32 data_sn,
511 	int f_bit)
512 {
513 	int ret = 0;
514 	struct iscsi_pdu *pdu = cmd->pdu_ptr;
515 
516 	pdu->data_sn = data_sn;
517 
518 	switch (pdu->status) {
519 	case ISCSI_PDU_NOT_RECEIVED:
520 		pdu->status = ISCSI_PDU_RECEIVED_OK;
521 		break;
522 	case ISCSI_PDU_CRC_FAILED:
523 		pdu->status = ISCSI_PDU_RECEIVED_OK;
524 		break;
525 	case ISCSI_PDU_TIMED_OUT:
526 		pdu->status = ISCSI_PDU_RECEIVED_OK;
527 		break;
528 	default:
529 		return DATAOUT_CANNOT_RECOVER;
530 	}
531 
532 	if (f_bit) {
533 		ret = iscsit_dataout_datapduinorder_no_fbit(cmd, pdu);
534 		if (ret == DATAOUT_CANNOT_RECOVER)
535 			return ret;
536 	}
537 
538 	return DATAOUT_NORMAL;
539 }
540 
541 static int iscsit_dataout_post_crc_passed(
542 	struct iscsi_cmd *cmd,
543 	unsigned char *buf)
544 {
545 	int ret, send_r2t = 0;
546 	struct iscsi_conn *conn = cmd->conn;
547 	struct iscsi_seq *seq = NULL;
548 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
549 	u32 payload_length = ntoh24(hdr->dlength);
550 
551 	if (cmd->unsolicited_data) {
552 		if ((cmd->first_burst_len + payload_length) ==
553 		     conn->sess->sess_ops->FirstBurstLength) {
554 			if (iscsit_dataout_update_r2t(cmd, be32_to_cpu(hdr->offset),
555 					payload_length) < 0)
556 				return DATAOUT_CANNOT_RECOVER;
557 			send_r2t = 1;
558 		}
559 
560 		if (!conn->sess->sess_ops->DataPDUInOrder) {
561 			ret = iscsit_dataout_update_datapduinorder_no(cmd,
562 				be32_to_cpu(hdr->datasn),
563 				(hdr->flags & ISCSI_FLAG_CMD_FINAL));
564 			if (ret == DATAOUT_CANNOT_RECOVER)
565 				return ret;
566 		}
567 
568 		cmd->first_burst_len += payload_length;
569 
570 		if (conn->sess->sess_ops->DataSequenceInOrder)
571 			cmd->data_sn++;
572 		else {
573 			seq = cmd->seq_ptr;
574 			seq->data_sn++;
575 			seq->offset += payload_length;
576 		}
577 
578 		if (send_r2t) {
579 			if (seq)
580 				seq->status = DATAOUT_SEQUENCE_COMPLETE;
581 			cmd->first_burst_len = 0;
582 			cmd->unsolicited_data = 0;
583 		}
584 	} else {
585 		if (conn->sess->sess_ops->DataSequenceInOrder) {
586 			if ((cmd->next_burst_len + payload_length) ==
587 			     conn->sess->sess_ops->MaxBurstLength) {
588 				if (iscsit_dataout_update_r2t(cmd,
589 						be32_to_cpu(hdr->offset),
590 						payload_length) < 0)
591 					return DATAOUT_CANNOT_RECOVER;
592 				send_r2t = 1;
593 			}
594 
595 			if (!conn->sess->sess_ops->DataPDUInOrder) {
596 				ret = iscsit_dataout_update_datapduinorder_no(
597 						cmd, be32_to_cpu(hdr->datasn),
598 						(hdr->flags & ISCSI_FLAG_CMD_FINAL));
599 				if (ret == DATAOUT_CANNOT_RECOVER)
600 					return ret;
601 			}
602 
603 			cmd->next_burst_len += payload_length;
604 			cmd->data_sn++;
605 
606 			if (send_r2t)
607 				cmd->next_burst_len = 0;
608 		} else {
609 			seq = cmd->seq_ptr;
610 
611 			if ((seq->next_burst_len + payload_length) ==
612 			     seq->xfer_len) {
613 				if (iscsit_dataout_update_r2t(cmd,
614 						be32_to_cpu(hdr->offset),
615 						payload_length) < 0)
616 					return DATAOUT_CANNOT_RECOVER;
617 				send_r2t = 1;
618 			}
619 
620 			if (!conn->sess->sess_ops->DataPDUInOrder) {
621 				ret = iscsit_dataout_update_datapduinorder_no(
622 						cmd, be32_to_cpu(hdr->datasn),
623 						(hdr->flags & ISCSI_FLAG_CMD_FINAL));
624 				if (ret == DATAOUT_CANNOT_RECOVER)
625 					return ret;
626 			}
627 
628 			seq->data_sn++;
629 			seq->offset += payload_length;
630 			seq->next_burst_len += payload_length;
631 
632 			if (send_r2t) {
633 				seq->next_burst_len = 0;
634 				seq->status = DATAOUT_SEQUENCE_COMPLETE;
635 			}
636 		}
637 	}
638 
639 	if (send_r2t && conn->sess->sess_ops->DataSequenceInOrder)
640 		cmd->data_sn = 0;
641 
642 	cmd->write_data_done += payload_length;
643 
644 	if (cmd->write_data_done == cmd->se_cmd.data_length)
645 		return DATAOUT_SEND_TO_TRANSPORT;
646 	else if (send_r2t)
647 		return DATAOUT_SEND_R2T;
648 	else
649 		return DATAOUT_NORMAL;
650 }
651 
652 static int iscsit_dataout_post_crc_failed(
653 	struct iscsi_cmd *cmd,
654 	unsigned char *buf)
655 {
656 	struct iscsi_conn *conn = cmd->conn;
657 	struct iscsi_pdu *pdu;
658 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
659 	u32 payload_length = ntoh24(hdr->dlength);
660 
661 	if (conn->sess->sess_ops->DataPDUInOrder)
662 		goto recover;
663 	/*
664 	 * The rest of this function is only called when DataPDUInOrder=No.
665 	 */
666 	pdu = cmd->pdu_ptr;
667 
668 	switch (pdu->status) {
669 	case ISCSI_PDU_NOT_RECEIVED:
670 		pdu->status = ISCSI_PDU_CRC_FAILED;
671 		break;
672 	case ISCSI_PDU_CRC_FAILED:
673 		break;
674 	case ISCSI_PDU_TIMED_OUT:
675 		pdu->status = ISCSI_PDU_CRC_FAILED;
676 		break;
677 	default:
678 		return DATAOUT_CANNOT_RECOVER;
679 	}
680 
681 recover:
682 	return iscsit_recover_dataout_sequence(cmd, be32_to_cpu(hdr->offset),
683 						payload_length);
684 }
685 
686 /*
687  *	Called from iscsit_handle_data_out() before DataOUT Payload is received
688  *	and CRC computed.
689  */
690 int iscsit_check_pre_dataout(
691 	struct iscsi_cmd *cmd,
692 	unsigned char *buf)
693 {
694 	int ret;
695 	struct iscsi_conn *conn = cmd->conn;
696 
697 	ret = iscsit_dataout_within_command_recovery_check(cmd, buf);
698 	if ((ret == DATAOUT_WITHIN_COMMAND_RECOVERY) ||
699 	    (ret == DATAOUT_CANNOT_RECOVER))
700 		return ret;
701 
702 	ret = iscsit_dataout_check_datasn(cmd, buf);
703 	if ((ret == DATAOUT_WITHIN_COMMAND_RECOVERY) ||
704 	    (ret == DATAOUT_CANNOT_RECOVER))
705 		return ret;
706 
707 	if (cmd->unsolicited_data) {
708 		ret = iscsit_dataout_check_unsolicited_sequence(cmd, buf);
709 		if ((ret == DATAOUT_WITHIN_COMMAND_RECOVERY) ||
710 		    (ret == DATAOUT_CANNOT_RECOVER))
711 			return ret;
712 	} else {
713 		ret = iscsit_dataout_check_sequence(cmd, buf);
714 		if ((ret == DATAOUT_WITHIN_COMMAND_RECOVERY) ||
715 		    (ret == DATAOUT_CANNOT_RECOVER))
716 			return ret;
717 	}
718 
719 	return (conn->sess->sess_ops->DataPDUInOrder) ?
720 		iscsit_dataout_pre_datapduinorder_yes(cmd, buf) :
721 		iscsit_dataout_pre_datapduinorder_no(cmd, buf);
722 }
723 
724 /*
725  *	Called from iscsit_handle_data_out() after DataOUT Payload is received
726  *	and CRC computed.
727  */
728 int iscsit_check_post_dataout(
729 	struct iscsi_cmd *cmd,
730 	unsigned char *buf,
731 	u8 data_crc_failed)
732 {
733 	struct iscsi_conn *conn = cmd->conn;
734 
735 	cmd->dataout_timeout_retries = 0;
736 
737 	if (!data_crc_failed)
738 		return iscsit_dataout_post_crc_passed(cmd, buf);
739 	else {
740 		if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
741 			pr_err("Unable to recover from DataOUT CRC"
742 				" failure while ERL=0, closing session.\n");
743 			iscsit_reject_cmd(cmd, ISCSI_REASON_DATA_DIGEST_ERROR,
744 					  buf);
745 			return DATAOUT_CANNOT_RECOVER;
746 		}
747 
748 		iscsit_reject_cmd(cmd, ISCSI_REASON_DATA_DIGEST_ERROR, buf);
749 		return iscsit_dataout_post_crc_failed(cmd, buf);
750 	}
751 }
752 
753 static void iscsit_handle_time2retain_timeout(unsigned long data)
754 {
755 	struct iscsi_session *sess = (struct iscsi_session *) data;
756 	struct iscsi_portal_group *tpg = sess->tpg;
757 	struct se_portal_group *se_tpg = &tpg->tpg_se_tpg;
758 
759 	spin_lock_bh(&se_tpg->session_lock);
760 	if (sess->time2retain_timer_flags & ISCSI_TF_STOP) {
761 		spin_unlock_bh(&se_tpg->session_lock);
762 		return;
763 	}
764 	if (atomic_read(&sess->session_reinstatement)) {
765 		pr_err("Exiting Time2Retain handler because"
766 				" session_reinstatement=1\n");
767 		spin_unlock_bh(&se_tpg->session_lock);
768 		return;
769 	}
770 	sess->time2retain_timer_flags |= ISCSI_TF_EXPIRED;
771 
772 	pr_err("Time2Retain timer expired for SID: %u, cleaning up"
773 			" iSCSI session.\n", sess->sid);
774 	{
775 	struct iscsi_tiqn *tiqn = tpg->tpg_tiqn;
776 
777 	if (tiqn) {
778 		spin_lock(&tiqn->sess_err_stats.lock);
779 		strcpy(tiqn->sess_err_stats.last_sess_fail_rem_name,
780 			(void *)sess->sess_ops->InitiatorName);
781 		tiqn->sess_err_stats.last_sess_failure_type =
782 				ISCSI_SESS_ERR_CXN_TIMEOUT;
783 		tiqn->sess_err_stats.cxn_timeout_errors++;
784 		atomic_long_inc(&sess->conn_timeout_errors);
785 		spin_unlock(&tiqn->sess_err_stats.lock);
786 	}
787 	}
788 
789 	spin_unlock_bh(&se_tpg->session_lock);
790 	target_put_session(sess->se_sess);
791 }
792 
793 void iscsit_start_time2retain_handler(struct iscsi_session *sess)
794 {
795 	int tpg_active;
796 	/*
797 	 * Only start Time2Retain timer when the associated TPG is still in
798 	 * an ACTIVE (eg: not disabled or shutdown) state.
799 	 */
800 	spin_lock(&sess->tpg->tpg_state_lock);
801 	tpg_active = (sess->tpg->tpg_state == TPG_STATE_ACTIVE);
802 	spin_unlock(&sess->tpg->tpg_state_lock);
803 
804 	if (!tpg_active)
805 		return;
806 
807 	if (sess->time2retain_timer_flags & ISCSI_TF_RUNNING)
808 		return;
809 
810 	pr_debug("Starting Time2Retain timer for %u seconds on"
811 		" SID: %u\n", sess->sess_ops->DefaultTime2Retain, sess->sid);
812 
813 	init_timer(&sess->time2retain_timer);
814 	sess->time2retain_timer.expires =
815 		(get_jiffies_64() + sess->sess_ops->DefaultTime2Retain * HZ);
816 	sess->time2retain_timer.data = (unsigned long)sess;
817 	sess->time2retain_timer.function = iscsit_handle_time2retain_timeout;
818 	sess->time2retain_timer_flags &= ~ISCSI_TF_STOP;
819 	sess->time2retain_timer_flags |= ISCSI_TF_RUNNING;
820 	add_timer(&sess->time2retain_timer);
821 }
822 
823 /*
824  *	Called with spin_lock_bh(&struct se_portal_group->session_lock) held
825  */
826 int iscsit_stop_time2retain_timer(struct iscsi_session *sess)
827 {
828 	struct iscsi_portal_group *tpg = sess->tpg;
829 	struct se_portal_group *se_tpg = &tpg->tpg_se_tpg;
830 
831 	if (sess->time2retain_timer_flags & ISCSI_TF_EXPIRED)
832 		return -1;
833 
834 	if (!(sess->time2retain_timer_flags & ISCSI_TF_RUNNING))
835 		return 0;
836 
837 	sess->time2retain_timer_flags |= ISCSI_TF_STOP;
838 	spin_unlock(&se_tpg->session_lock);
839 
840 	del_timer_sync(&sess->time2retain_timer);
841 
842 	spin_lock(&se_tpg->session_lock);
843 	sess->time2retain_timer_flags &= ~ISCSI_TF_RUNNING;
844 	pr_debug("Stopped Time2Retain Timer for SID: %u\n",
845 			sess->sid);
846 	return 0;
847 }
848 
849 void iscsit_connection_reinstatement_rcfr(struct iscsi_conn *conn)
850 {
851 	spin_lock_bh(&conn->state_lock);
852 	if (atomic_read(&conn->connection_exit)) {
853 		spin_unlock_bh(&conn->state_lock);
854 		goto sleep;
855 	}
856 
857 	if (atomic_read(&conn->transport_failed)) {
858 		spin_unlock_bh(&conn->state_lock);
859 		goto sleep;
860 	}
861 	spin_unlock_bh(&conn->state_lock);
862 
863 	iscsi_thread_set_force_reinstatement(conn);
864 
865 sleep:
866 	wait_for_completion(&conn->conn_wait_rcfr_comp);
867 	complete(&conn->conn_post_wait_comp);
868 }
869 
870 void iscsit_cause_connection_reinstatement(struct iscsi_conn *conn, int sleep)
871 {
872 	spin_lock_bh(&conn->state_lock);
873 	if (atomic_read(&conn->connection_exit)) {
874 		spin_unlock_bh(&conn->state_lock);
875 		return;
876 	}
877 
878 	if (atomic_read(&conn->transport_failed)) {
879 		spin_unlock_bh(&conn->state_lock);
880 		return;
881 	}
882 
883 	if (atomic_read(&conn->connection_reinstatement)) {
884 		spin_unlock_bh(&conn->state_lock);
885 		return;
886 	}
887 
888 	if (iscsi_thread_set_force_reinstatement(conn) < 0) {
889 		spin_unlock_bh(&conn->state_lock);
890 		return;
891 	}
892 
893 	atomic_set(&conn->connection_reinstatement, 1);
894 	if (!sleep) {
895 		spin_unlock_bh(&conn->state_lock);
896 		return;
897 	}
898 
899 	atomic_set(&conn->sleep_on_conn_wait_comp, 1);
900 	spin_unlock_bh(&conn->state_lock);
901 
902 	wait_for_completion(&conn->conn_wait_comp);
903 	complete(&conn->conn_post_wait_comp);
904 }
905 EXPORT_SYMBOL(iscsit_cause_connection_reinstatement);
906 
907 void iscsit_fall_back_to_erl0(struct iscsi_session *sess)
908 {
909 	pr_debug("Falling back to ErrorRecoveryLevel=0 for SID:"
910 			" %u\n", sess->sid);
911 
912 	atomic_set(&sess->session_fall_back_to_erl0, 1);
913 }
914 
915 static void iscsit_handle_connection_cleanup(struct iscsi_conn *conn)
916 {
917 	struct iscsi_session *sess = conn->sess;
918 
919 	if ((sess->sess_ops->ErrorRecoveryLevel == 2) &&
920 	    !atomic_read(&sess->session_reinstatement) &&
921 	    !atomic_read(&sess->session_fall_back_to_erl0))
922 		iscsit_connection_recovery_transport_reset(conn);
923 	else {
924 		pr_debug("Performing cleanup for failed iSCSI"
925 			" Connection ID: %hu from %s\n", conn->cid,
926 			sess->sess_ops->InitiatorName);
927 		iscsit_close_connection(conn);
928 	}
929 }
930 
931 void iscsit_take_action_for_connection_exit(struct iscsi_conn *conn)
932 {
933 	spin_lock_bh(&conn->state_lock);
934 	if (atomic_read(&conn->connection_exit)) {
935 		spin_unlock_bh(&conn->state_lock);
936 		return;
937 	}
938 	atomic_set(&conn->connection_exit, 1);
939 
940 	if (conn->conn_state == TARG_CONN_STATE_IN_LOGOUT) {
941 		spin_unlock_bh(&conn->state_lock);
942 		iscsit_close_connection(conn);
943 		return;
944 	}
945 
946 	if (conn->conn_state == TARG_CONN_STATE_CLEANUP_WAIT) {
947 		spin_unlock_bh(&conn->state_lock);
948 		return;
949 	}
950 
951 	pr_debug("Moving to TARG_CONN_STATE_CLEANUP_WAIT.\n");
952 	conn->conn_state = TARG_CONN_STATE_CLEANUP_WAIT;
953 	spin_unlock_bh(&conn->state_lock);
954 
955 	iscsit_handle_connection_cleanup(conn);
956 }
957 
958 /*
959  *	This is the simple function that makes the magic of
960  *	sync and steering happen in the follow paradoxical order:
961  *
962  *	0) Receive conn->of_marker (bytes left until next OFMarker)
963  *	   bytes into an offload buffer.  When we pass the exact number
964  *	   of bytes in conn->of_marker, iscsit_dump_data_payload() and hence
965  *	   rx_data() will automatically receive the identical u32 marker
966  *	   values and store it in conn->of_marker_offset;
967  *	1) Now conn->of_marker_offset will contain the offset to the start
968  *	   of the next iSCSI PDU.  Dump these remaining bytes into another
969  *	   offload buffer.
970  *	2) We are done!
971  *	   Next byte in the TCP stream will contain the next iSCSI PDU!
972  *	   Cool Huh?!
973  */
974 int iscsit_recover_from_unknown_opcode(struct iscsi_conn *conn)
975 {
976 	/*
977 	 * Make sure the remaining bytes to next maker is a sane value.
978 	 */
979 	if (conn->of_marker > (conn->conn_ops->OFMarkInt * 4)) {
980 		pr_err("Remaining bytes to OFMarker: %u exceeds"
981 			" OFMarkInt bytes: %u.\n", conn->of_marker,
982 				conn->conn_ops->OFMarkInt * 4);
983 		return -1;
984 	}
985 
986 	pr_debug("Advancing %u bytes in TCP stream to get to the"
987 			" next OFMarker.\n", conn->of_marker);
988 
989 	if (iscsit_dump_data_payload(conn, conn->of_marker, 0) < 0)
990 		return -1;
991 
992 	/*
993 	 * Make sure the offset marker we retrived is a valid value.
994 	 */
995 	if (conn->of_marker_offset > (ISCSI_HDR_LEN + (ISCSI_CRC_LEN * 2) +
996 	    conn->conn_ops->MaxRecvDataSegmentLength)) {
997 		pr_err("OfMarker offset value: %u exceeds limit.\n",
998 			conn->of_marker_offset);
999 		return -1;
1000 	}
1001 
1002 	pr_debug("Discarding %u bytes of TCP stream to get to the"
1003 			" next iSCSI Opcode.\n", conn->of_marker_offset);
1004 
1005 	if (iscsit_dump_data_payload(conn, conn->of_marker_offset, 0) < 0)
1006 		return -1;
1007 
1008 	return 0;
1009 }
1010