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 <target/iscsi/iscsi_transport.h>
26 #include "iscsi_target_seq_pdu_list.h"
27 #include "iscsi_target_tq.h"
28 #include "iscsi_target_erl0.h"
29 #include "iscsi_target_erl1.h"
30 #include "iscsi_target_erl2.h"
31 #include "iscsi_target_util.h"
32 #include "iscsi_target.h"
33 
34 /*
35  *	Used to set values in struct iscsi_cmd that iscsit_dataout_check_sequence()
36  *	checks against to determine a PDU's Offset+Length is within the current
37  *	DataOUT Sequence.  Used for DataSequenceInOrder=Yes only.
38  */
39 void iscsit_set_dataout_sequence_values(
40 	struct iscsi_cmd *cmd)
41 {
42 	struct iscsi_conn *conn = cmd->conn;
43 	/*
44 	 * Still set seq_start_offset and seq_end_offset for Unsolicited
45 	 * DataOUT, even if DataSequenceInOrder=No.
46 	 */
47 	if (cmd->unsolicited_data) {
48 		cmd->seq_start_offset = cmd->write_data_done;
49 		cmd->seq_end_offset = (cmd->write_data_done +
50 			((cmd->se_cmd.data_length >
51 			  conn->sess->sess_ops->FirstBurstLength) ?
52 			 conn->sess->sess_ops->FirstBurstLength : cmd->se_cmd.data_length));
53 		return;
54 	}
55 
56 	if (!conn->sess->sess_ops->DataSequenceInOrder)
57 		return;
58 
59 	if (!cmd->seq_start_offset && !cmd->seq_end_offset) {
60 		cmd->seq_start_offset = cmd->write_data_done;
61 		cmd->seq_end_offset = (cmd->se_cmd.data_length >
62 			conn->sess->sess_ops->MaxBurstLength) ?
63 			(cmd->write_data_done +
64 			conn->sess->sess_ops->MaxBurstLength) : cmd->se_cmd.data_length;
65 	} else {
66 		cmd->seq_start_offset = cmd->seq_end_offset;
67 		cmd->seq_end_offset = ((cmd->seq_end_offset +
68 			conn->sess->sess_ops->MaxBurstLength) >=
69 			cmd->se_cmd.data_length) ? cmd->se_cmd.data_length :
70 			(cmd->seq_end_offset +
71 			 conn->sess->sess_ops->MaxBurstLength);
72 	}
73 }
74 
75 static int iscsit_dataout_within_command_recovery_check(
76 	struct iscsi_cmd *cmd,
77 	unsigned char *buf)
78 {
79 	struct iscsi_conn *conn = cmd->conn;
80 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
81 	u32 payload_length = ntoh24(hdr->dlength);
82 
83 	/*
84 	 * We do the within-command recovery checks here as it is
85 	 * the first function called in iscsi_check_pre_dataout().
86 	 * Basically, if we are in within-command recovery and
87 	 * the PDU does not contain the offset the sequence needs,
88 	 * dump the payload.
89 	 *
90 	 * This only applies to DataPDUInOrder=Yes, for
91 	 * DataPDUInOrder=No we only re-request the failed PDU
92 	 * and check that all PDUs in a sequence are received
93 	 * upon end of sequence.
94 	 */
95 	if (conn->sess->sess_ops->DataSequenceInOrder) {
96 		if ((cmd->cmd_flags & ICF_WITHIN_COMMAND_RECOVERY) &&
97 		    cmd->write_data_done != be32_to_cpu(hdr->offset))
98 			goto dump;
99 
100 		cmd->cmd_flags &= ~ICF_WITHIN_COMMAND_RECOVERY;
101 	} else {
102 		struct iscsi_seq *seq;
103 
104 		seq = iscsit_get_seq_holder(cmd, be32_to_cpu(hdr->offset),
105 					    payload_length);
106 		if (!seq)
107 			return DATAOUT_CANNOT_RECOVER;
108 		/*
109 		 * Set the struct iscsi_seq pointer to reuse later.
110 		 */
111 		cmd->seq_ptr = seq;
112 
113 		if (conn->sess->sess_ops->DataPDUInOrder) {
114 			if (seq->status ==
115 			    DATAOUT_SEQUENCE_WITHIN_COMMAND_RECOVERY &&
116 			   (seq->offset != be32_to_cpu(hdr->offset) ||
117 			    seq->data_sn != be32_to_cpu(hdr->datasn)))
118 				goto dump;
119 		} else {
120 			if (seq->status ==
121 			     DATAOUT_SEQUENCE_WITHIN_COMMAND_RECOVERY &&
122 			    seq->data_sn != be32_to_cpu(hdr->datasn))
123 				goto dump;
124 		}
125 
126 		if (seq->status == DATAOUT_SEQUENCE_COMPLETE)
127 			goto dump;
128 
129 		if (seq->status != DATAOUT_SEQUENCE_COMPLETE)
130 			seq->status = 0;
131 	}
132 
133 	return DATAOUT_NORMAL;
134 
135 dump:
136 	pr_err("Dumping DataOUT PDU Offset: %u Length: %d DataSN:"
137 		" 0x%08x\n", hdr->offset, payload_length, hdr->datasn);
138 	return iscsit_dump_data_payload(conn, payload_length, 1);
139 }
140 
141 static int iscsit_dataout_check_unsolicited_sequence(
142 	struct iscsi_cmd *cmd,
143 	unsigned char *buf)
144 {
145 	u32 first_burst_len;
146 	struct iscsi_conn *conn = cmd->conn;
147 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
148 	u32 payload_length = ntoh24(hdr->dlength);
149 
150 
151 	if ((be32_to_cpu(hdr->offset) < cmd->seq_start_offset) ||
152 	   ((be32_to_cpu(hdr->offset) + payload_length) > cmd->seq_end_offset)) {
153 		pr_err("Command ITT: 0x%08x with Offset: %u,"
154 		" Length: %u outside of Unsolicited Sequence %u:%u while"
155 		" DataSequenceInOrder=Yes.\n", cmd->init_task_tag,
156 		be32_to_cpu(hdr->offset), payload_length, cmd->seq_start_offset,
157 			cmd->seq_end_offset);
158 		return DATAOUT_CANNOT_RECOVER;
159 	}
160 
161 	first_burst_len = (cmd->first_burst_len + payload_length);
162 
163 	if (first_burst_len > conn->sess->sess_ops->FirstBurstLength) {
164 		pr_err("Total %u bytes exceeds FirstBurstLength: %u"
165 			" for this Unsolicited DataOut Burst.\n",
166 			first_burst_len, conn->sess->sess_ops->FirstBurstLength);
167 		transport_send_check_condition_and_sense(&cmd->se_cmd,
168 				TCM_INCORRECT_AMOUNT_OF_DATA, 0);
169 		return DATAOUT_CANNOT_RECOVER;
170 	}
171 
172 	/*
173 	 * Perform various MaxBurstLength and ISCSI_FLAG_CMD_FINAL sanity
174 	 * checks for the current Unsolicited DataOUT Sequence.
175 	 */
176 	if (hdr->flags & ISCSI_FLAG_CMD_FINAL) {
177 		/*
178 		 * Ignore ISCSI_FLAG_CMD_FINAL checks while DataPDUInOrder=No, end of
179 		 * sequence checks are handled in
180 		 * iscsit_dataout_datapduinorder_no_fbit().
181 		 */
182 		if (!conn->sess->sess_ops->DataPDUInOrder)
183 			goto out;
184 
185 		if ((first_burst_len != cmd->se_cmd.data_length) &&
186 		    (first_burst_len != conn->sess->sess_ops->FirstBurstLength)) {
187 			pr_err("Unsolicited non-immediate data"
188 			" received %u does not equal FirstBurstLength: %u, and"
189 			" does not equal ExpXferLen %u.\n", first_burst_len,
190 				conn->sess->sess_ops->FirstBurstLength,
191 				cmd->se_cmd.data_length);
192 			transport_send_check_condition_and_sense(&cmd->se_cmd,
193 					TCM_INCORRECT_AMOUNT_OF_DATA, 0);
194 			return DATAOUT_CANNOT_RECOVER;
195 		}
196 	} else {
197 		if (first_burst_len == conn->sess->sess_ops->FirstBurstLength) {
198 			pr_err("Command ITT: 0x%08x reached"
199 			" FirstBurstLength: %u, but ISCSI_FLAG_CMD_FINAL is not set. protocol"
200 				" error.\n", cmd->init_task_tag,
201 				conn->sess->sess_ops->FirstBurstLength);
202 			return DATAOUT_CANNOT_RECOVER;
203 		}
204 		if (first_burst_len == cmd->se_cmd.data_length) {
205 			pr_err("Command ITT: 0x%08x reached"
206 			" ExpXferLen: %u, but ISCSI_FLAG_CMD_FINAL is not set. protocol"
207 			" error.\n", cmd->init_task_tag, cmd->se_cmd.data_length);
208 			return DATAOUT_CANNOT_RECOVER;
209 		}
210 	}
211 
212 out:
213 	return DATAOUT_NORMAL;
214 }
215 
216 static int iscsit_dataout_check_sequence(
217 	struct iscsi_cmd *cmd,
218 	unsigned char *buf)
219 {
220 	u32 next_burst_len;
221 	struct iscsi_conn *conn = cmd->conn;
222 	struct iscsi_seq *seq = NULL;
223 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
224 	u32 payload_length = ntoh24(hdr->dlength);
225 
226 	/*
227 	 * For DataSequenceInOrder=Yes: Check that the offset and offset+length
228 	 * is within range as defined by iscsi_set_dataout_sequence_values().
229 	 *
230 	 * For DataSequenceInOrder=No: Check that an struct iscsi_seq exists for
231 	 * offset+length tuple.
232 	 */
233 	if (conn->sess->sess_ops->DataSequenceInOrder) {
234 		/*
235 		 * Due to possibility of recovery DataOUT sent by the initiator
236 		 * fullfilling an Recovery R2T, it's best to just dump the
237 		 * payload here, instead of erroring out.
238 		 */
239 		if ((be32_to_cpu(hdr->offset) < cmd->seq_start_offset) ||
240 		   ((be32_to_cpu(hdr->offset) + payload_length) > cmd->seq_end_offset)) {
241 			pr_err("Command ITT: 0x%08x with Offset: %u,"
242 			" Length: %u outside of Sequence %u:%u while"
243 			" DataSequenceInOrder=Yes.\n", cmd->init_task_tag,
244 			be32_to_cpu(hdr->offset), payload_length, cmd->seq_start_offset,
245 				cmd->seq_end_offset);
246 
247 			if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
248 				return DATAOUT_CANNOT_RECOVER;
249 			return DATAOUT_WITHIN_COMMAND_RECOVERY;
250 		}
251 
252 		next_burst_len = (cmd->next_burst_len + payload_length);
253 	} else {
254 		seq = iscsit_get_seq_holder(cmd, be32_to_cpu(hdr->offset),
255 					    payload_length);
256 		if (!seq)
257 			return DATAOUT_CANNOT_RECOVER;
258 		/*
259 		 * Set the struct iscsi_seq pointer to reuse later.
260 		 */
261 		cmd->seq_ptr = seq;
262 
263 		if (seq->status == DATAOUT_SEQUENCE_COMPLETE) {
264 			if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
265 				return DATAOUT_CANNOT_RECOVER;
266 			return DATAOUT_WITHIN_COMMAND_RECOVERY;
267 		}
268 
269 		next_burst_len = (seq->next_burst_len + payload_length);
270 	}
271 
272 	if (next_burst_len > conn->sess->sess_ops->MaxBurstLength) {
273 		pr_err("Command ITT: 0x%08x, NextBurstLength: %u and"
274 			" Length: %u exceeds MaxBurstLength: %u. protocol"
275 			" error.\n", cmd->init_task_tag,
276 			(next_burst_len - payload_length),
277 			payload_length, conn->sess->sess_ops->MaxBurstLength);
278 		return DATAOUT_CANNOT_RECOVER;
279 	}
280 
281 	/*
282 	 * Perform various MaxBurstLength and ISCSI_FLAG_CMD_FINAL sanity
283 	 * checks for the current DataOUT Sequence.
284 	 */
285 	if (hdr->flags & ISCSI_FLAG_CMD_FINAL) {
286 		/*
287 		 * Ignore ISCSI_FLAG_CMD_FINAL checks while DataPDUInOrder=No, end of
288 		 * sequence checks are handled in
289 		 * iscsit_dataout_datapduinorder_no_fbit().
290 		 */
291 		if (!conn->sess->sess_ops->DataPDUInOrder)
292 			goto out;
293 
294 		if (conn->sess->sess_ops->DataSequenceInOrder) {
295 			if ((next_burst_len <
296 			     conn->sess->sess_ops->MaxBurstLength) &&
297 			   ((cmd->write_data_done + payload_length) <
298 			     cmd->se_cmd.data_length)) {
299 				pr_err("Command ITT: 0x%08x set ISCSI_FLAG_CMD_FINAL"
300 				" before end of DataOUT sequence, protocol"
301 				" error.\n", cmd->init_task_tag);
302 				return DATAOUT_CANNOT_RECOVER;
303 			}
304 		} else {
305 			if (next_burst_len < seq->xfer_len) {
306 				pr_err("Command ITT: 0x%08x set ISCSI_FLAG_CMD_FINAL"
307 				" before end of DataOUT sequence, protocol"
308 				" error.\n", cmd->init_task_tag);
309 				return DATAOUT_CANNOT_RECOVER;
310 			}
311 		}
312 	} else {
313 		if (conn->sess->sess_ops->DataSequenceInOrder) {
314 			if (next_burst_len ==
315 					conn->sess->sess_ops->MaxBurstLength) {
316 				pr_err("Command ITT: 0x%08x reached"
317 				" MaxBurstLength: %u, but ISCSI_FLAG_CMD_FINAL is"
318 				" not set, protocol error.", cmd->init_task_tag,
319 					conn->sess->sess_ops->MaxBurstLength);
320 				return DATAOUT_CANNOT_RECOVER;
321 			}
322 			if ((cmd->write_data_done + payload_length) ==
323 					cmd->se_cmd.data_length) {
324 				pr_err("Command ITT: 0x%08x reached"
325 				" last DataOUT PDU in sequence but ISCSI_FLAG_"
326 				"CMD_FINAL is not set, protocol error.\n",
327 					cmd->init_task_tag);
328 				return DATAOUT_CANNOT_RECOVER;
329 			}
330 		} else {
331 			if (next_burst_len == seq->xfer_len) {
332 				pr_err("Command ITT: 0x%08x reached"
333 				" last DataOUT PDU in sequence but ISCSI_FLAG_"
334 				"CMD_FINAL is not set, protocol error.\n",
335 					cmd->init_task_tag);
336 				return DATAOUT_CANNOT_RECOVER;
337 			}
338 		}
339 	}
340 
341 out:
342 	return DATAOUT_NORMAL;
343 }
344 
345 static int iscsit_dataout_check_datasn(
346 	struct iscsi_cmd *cmd,
347 	unsigned char *buf)
348 {
349 	u32 data_sn = 0;
350 	struct iscsi_conn *conn = cmd->conn;
351 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
352 	u32 payload_length = ntoh24(hdr->dlength);
353 
354 	/*
355 	 * Considering the target has no method of re-requesting DataOUT
356 	 * by DataSN, if we receieve a greater DataSN than expected we
357 	 * assume the functions for DataPDUInOrder=[Yes,No] below will
358 	 * handle it.
359 	 *
360 	 * If the DataSN is less than expected, dump the payload.
361 	 */
362 	if (conn->sess->sess_ops->DataSequenceInOrder)
363 		data_sn = cmd->data_sn;
364 	else {
365 		struct iscsi_seq *seq = cmd->seq_ptr;
366 		data_sn = seq->data_sn;
367 	}
368 
369 	if (be32_to_cpu(hdr->datasn) > data_sn) {
370 		pr_err("Command ITT: 0x%08x, received DataSN: 0x%08x"
371 			" higher than expected 0x%08x.\n", cmd->init_task_tag,
372 				be32_to_cpu(hdr->datasn), data_sn);
373 		goto recover;
374 	} else if (be32_to_cpu(hdr->datasn) < data_sn) {
375 		pr_err("Command ITT: 0x%08x, received DataSN: 0x%08x"
376 			" lower than expected 0x%08x, discarding payload.\n",
377 			cmd->init_task_tag, be32_to_cpu(hdr->datasn), data_sn);
378 		goto dump;
379 	}
380 
381 	return DATAOUT_NORMAL;
382 
383 recover:
384 	if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
385 		pr_err("Unable to perform within-command recovery"
386 				" while ERL=0.\n");
387 		return DATAOUT_CANNOT_RECOVER;
388 	}
389 dump:
390 	if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
391 		return DATAOUT_CANNOT_RECOVER;
392 
393 	return DATAOUT_WITHIN_COMMAND_RECOVERY;
394 }
395 
396 static int iscsit_dataout_pre_datapduinorder_yes(
397 	struct iscsi_cmd *cmd,
398 	unsigned char *buf)
399 {
400 	int dump = 0, recovery = 0;
401 	struct iscsi_conn *conn = cmd->conn;
402 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
403 	u32 payload_length = ntoh24(hdr->dlength);
404 
405 	/*
406 	 * For DataSequenceInOrder=Yes: If the offset is greater than the global
407 	 * DataPDUInOrder=Yes offset counter in struct iscsi_cmd a protcol error has
408 	 * occurred and fail the connection.
409 	 *
410 	 * For DataSequenceInOrder=No: If the offset is greater than the per
411 	 * sequence DataPDUInOrder=Yes offset counter in struct iscsi_seq a protocol
412 	 * error has occurred and fail the connection.
413 	 */
414 	if (conn->sess->sess_ops->DataSequenceInOrder) {
415 		if (be32_to_cpu(hdr->offset) != cmd->write_data_done) {
416 			pr_err("Command ITT: 0x%08x, received offset"
417 			" %u different than expected %u.\n", cmd->init_task_tag,
418 				be32_to_cpu(hdr->offset), cmd->write_data_done);
419 			recovery = 1;
420 			goto recover;
421 		}
422 	} else {
423 		struct iscsi_seq *seq = cmd->seq_ptr;
424 
425 		if (be32_to_cpu(hdr->offset) > seq->offset) {
426 			pr_err("Command ITT: 0x%08x, received offset"
427 			" %u greater than expected %u.\n", cmd->init_task_tag,
428 				be32_to_cpu(hdr->offset), seq->offset);
429 			recovery = 1;
430 			goto recover;
431 		} else if (be32_to_cpu(hdr->offset) < seq->offset) {
432 			pr_err("Command ITT: 0x%08x, received offset"
433 			" %u less than expected %u, discarding payload.\n",
434 				cmd->init_task_tag, be32_to_cpu(hdr->offset),
435 				seq->offset);
436 			dump = 1;
437 			goto dump;
438 		}
439 	}
440 
441 	return DATAOUT_NORMAL;
442 
443 recover:
444 	if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
445 		pr_err("Unable to perform within-command recovery"
446 				" while ERL=0.\n");
447 		return DATAOUT_CANNOT_RECOVER;
448 	}
449 dump:
450 	if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
451 		return DATAOUT_CANNOT_RECOVER;
452 
453 	return (recovery) ? iscsit_recover_dataout_sequence(cmd,
454 		be32_to_cpu(hdr->offset), payload_length) :
455 	       (dump) ? DATAOUT_WITHIN_COMMAND_RECOVERY : DATAOUT_NORMAL;
456 }
457 
458 static int iscsit_dataout_pre_datapduinorder_no(
459 	struct iscsi_cmd *cmd,
460 	unsigned char *buf)
461 {
462 	struct iscsi_pdu *pdu;
463 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
464 	u32 payload_length = ntoh24(hdr->dlength);
465 
466 	pdu = iscsit_get_pdu_holder(cmd, be32_to_cpu(hdr->offset),
467 				    payload_length);
468 	if (!pdu)
469 		return DATAOUT_CANNOT_RECOVER;
470 
471 	cmd->pdu_ptr = pdu;
472 
473 	switch (pdu->status) {
474 	case ISCSI_PDU_NOT_RECEIVED:
475 	case ISCSI_PDU_CRC_FAILED:
476 	case ISCSI_PDU_TIMED_OUT:
477 		break;
478 	case ISCSI_PDU_RECEIVED_OK:
479 		pr_err("Command ITT: 0x%08x received already gotten"
480 			" Offset: %u, Length: %u\n", cmd->init_task_tag,
481 				be32_to_cpu(hdr->offset), payload_length);
482 		return iscsit_dump_data_payload(cmd->conn, payload_length, 1);
483 	default:
484 		return DATAOUT_CANNOT_RECOVER;
485 	}
486 
487 	return DATAOUT_NORMAL;
488 }
489 
490 static int iscsit_dataout_update_r2t(struct iscsi_cmd *cmd, u32 offset, u32 length)
491 {
492 	struct iscsi_r2t *r2t;
493 
494 	if (cmd->unsolicited_data)
495 		return 0;
496 
497 	r2t = iscsit_get_r2t_for_eos(cmd, offset, length);
498 	if (!r2t)
499 		return -1;
500 
501 	spin_lock_bh(&cmd->r2t_lock);
502 	r2t->seq_complete = 1;
503 	cmd->outstanding_r2ts--;
504 	spin_unlock_bh(&cmd->r2t_lock);
505 
506 	return 0;
507 }
508 
509 static int iscsit_dataout_update_datapduinorder_no(
510 	struct iscsi_cmd *cmd,
511 	u32 data_sn,
512 	int f_bit)
513 {
514 	int ret = 0;
515 	struct iscsi_pdu *pdu = cmd->pdu_ptr;
516 
517 	pdu->data_sn = data_sn;
518 
519 	switch (pdu->status) {
520 	case ISCSI_PDU_NOT_RECEIVED:
521 		pdu->status = ISCSI_PDU_RECEIVED_OK;
522 		break;
523 	case ISCSI_PDU_CRC_FAILED:
524 		pdu->status = ISCSI_PDU_RECEIVED_OK;
525 		break;
526 	case ISCSI_PDU_TIMED_OUT:
527 		pdu->status = ISCSI_PDU_RECEIVED_OK;
528 		break;
529 	default:
530 		return DATAOUT_CANNOT_RECOVER;
531 	}
532 
533 	if (f_bit) {
534 		ret = iscsit_dataout_datapduinorder_no_fbit(cmd, pdu);
535 		if (ret == DATAOUT_CANNOT_RECOVER)
536 			return ret;
537 	}
538 
539 	return DATAOUT_NORMAL;
540 }
541 
542 static int iscsit_dataout_post_crc_passed(
543 	struct iscsi_cmd *cmd,
544 	unsigned char *buf)
545 {
546 	int ret, send_r2t = 0;
547 	struct iscsi_conn *conn = cmd->conn;
548 	struct iscsi_seq *seq = NULL;
549 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
550 	u32 payload_length = ntoh24(hdr->dlength);
551 
552 	if (cmd->unsolicited_data) {
553 		if ((cmd->first_burst_len + payload_length) ==
554 		     conn->sess->sess_ops->FirstBurstLength) {
555 			if (iscsit_dataout_update_r2t(cmd, be32_to_cpu(hdr->offset),
556 					payload_length) < 0)
557 				return DATAOUT_CANNOT_RECOVER;
558 			send_r2t = 1;
559 		}
560 
561 		if (!conn->sess->sess_ops->DataPDUInOrder) {
562 			ret = iscsit_dataout_update_datapduinorder_no(cmd,
563 				be32_to_cpu(hdr->datasn),
564 				(hdr->flags & ISCSI_FLAG_CMD_FINAL));
565 			if (ret == DATAOUT_CANNOT_RECOVER)
566 				return ret;
567 		}
568 
569 		cmd->first_burst_len += payload_length;
570 
571 		if (conn->sess->sess_ops->DataSequenceInOrder)
572 			cmd->data_sn++;
573 		else {
574 			seq = cmd->seq_ptr;
575 			seq->data_sn++;
576 			seq->offset += payload_length;
577 		}
578 
579 		if (send_r2t) {
580 			if (seq)
581 				seq->status = DATAOUT_SEQUENCE_COMPLETE;
582 			cmd->first_burst_len = 0;
583 			cmd->unsolicited_data = 0;
584 		}
585 	} else {
586 		if (conn->sess->sess_ops->DataSequenceInOrder) {
587 			if ((cmd->next_burst_len + payload_length) ==
588 			     conn->sess->sess_ops->MaxBurstLength) {
589 				if (iscsit_dataout_update_r2t(cmd,
590 						be32_to_cpu(hdr->offset),
591 						payload_length) < 0)
592 					return DATAOUT_CANNOT_RECOVER;
593 				send_r2t = 1;
594 			}
595 
596 			if (!conn->sess->sess_ops->DataPDUInOrder) {
597 				ret = iscsit_dataout_update_datapduinorder_no(
598 						cmd, be32_to_cpu(hdr->datasn),
599 						(hdr->flags & ISCSI_FLAG_CMD_FINAL));
600 				if (ret == DATAOUT_CANNOT_RECOVER)
601 					return ret;
602 			}
603 
604 			cmd->next_burst_len += payload_length;
605 			cmd->data_sn++;
606 
607 			if (send_r2t)
608 				cmd->next_burst_len = 0;
609 		} else {
610 			seq = cmd->seq_ptr;
611 
612 			if ((seq->next_burst_len + payload_length) ==
613 			     seq->xfer_len) {
614 				if (iscsit_dataout_update_r2t(cmd,
615 						be32_to_cpu(hdr->offset),
616 						payload_length) < 0)
617 					return DATAOUT_CANNOT_RECOVER;
618 				send_r2t = 1;
619 			}
620 
621 			if (!conn->sess->sess_ops->DataPDUInOrder) {
622 				ret = iscsit_dataout_update_datapduinorder_no(
623 						cmd, be32_to_cpu(hdr->datasn),
624 						(hdr->flags & ISCSI_FLAG_CMD_FINAL));
625 				if (ret == DATAOUT_CANNOT_RECOVER)
626 					return ret;
627 			}
628 
629 			seq->data_sn++;
630 			seq->offset += payload_length;
631 			seq->next_burst_len += payload_length;
632 
633 			if (send_r2t) {
634 				seq->next_burst_len = 0;
635 				seq->status = DATAOUT_SEQUENCE_COMPLETE;
636 			}
637 		}
638 	}
639 
640 	if (send_r2t && conn->sess->sess_ops->DataSequenceInOrder)
641 		cmd->data_sn = 0;
642 
643 	cmd->write_data_done += payload_length;
644 
645 	if (cmd->write_data_done == cmd->se_cmd.data_length)
646 		return DATAOUT_SEND_TO_TRANSPORT;
647 	else if (send_r2t)
648 		return DATAOUT_SEND_R2T;
649 	else
650 		return DATAOUT_NORMAL;
651 }
652 
653 static int iscsit_dataout_post_crc_failed(
654 	struct iscsi_cmd *cmd,
655 	unsigned char *buf)
656 {
657 	struct iscsi_conn *conn = cmd->conn;
658 	struct iscsi_pdu *pdu;
659 	struct iscsi_data *hdr = (struct iscsi_data *) buf;
660 	u32 payload_length = ntoh24(hdr->dlength);
661 
662 	if (conn->sess->sess_ops->DataPDUInOrder)
663 		goto recover;
664 	/*
665 	 * The rest of this function is only called when DataPDUInOrder=No.
666 	 */
667 	pdu = cmd->pdu_ptr;
668 
669 	switch (pdu->status) {
670 	case ISCSI_PDU_NOT_RECEIVED:
671 		pdu->status = ISCSI_PDU_CRC_FAILED;
672 		break;
673 	case ISCSI_PDU_CRC_FAILED:
674 		break;
675 	case ISCSI_PDU_TIMED_OUT:
676 		pdu->status = ISCSI_PDU_CRC_FAILED;
677 		break;
678 	default:
679 		return DATAOUT_CANNOT_RECOVER;
680 	}
681 
682 recover:
683 	return iscsit_recover_dataout_sequence(cmd, be32_to_cpu(hdr->offset),
684 						payload_length);
685 }
686 
687 /*
688  *	Called from iscsit_handle_data_out() before DataOUT Payload is received
689  *	and CRC computed.
690  */
691 int iscsit_check_pre_dataout(
692 	struct iscsi_cmd *cmd,
693 	unsigned char *buf)
694 {
695 	int ret;
696 	struct iscsi_conn *conn = cmd->conn;
697 
698 	ret = iscsit_dataout_within_command_recovery_check(cmd, buf);
699 	if ((ret == DATAOUT_WITHIN_COMMAND_RECOVERY) ||
700 	    (ret == DATAOUT_CANNOT_RECOVER))
701 		return ret;
702 
703 	ret = iscsit_dataout_check_datasn(cmd, buf);
704 	if ((ret == DATAOUT_WITHIN_COMMAND_RECOVERY) ||
705 	    (ret == DATAOUT_CANNOT_RECOVER))
706 		return ret;
707 
708 	if (cmd->unsolicited_data) {
709 		ret = iscsit_dataout_check_unsolicited_sequence(cmd, buf);
710 		if ((ret == DATAOUT_WITHIN_COMMAND_RECOVERY) ||
711 		    (ret == DATAOUT_CANNOT_RECOVER))
712 			return ret;
713 	} else {
714 		ret = iscsit_dataout_check_sequence(cmd, buf);
715 		if ((ret == DATAOUT_WITHIN_COMMAND_RECOVERY) ||
716 		    (ret == DATAOUT_CANNOT_RECOVER))
717 			return ret;
718 	}
719 
720 	return (conn->sess->sess_ops->DataPDUInOrder) ?
721 		iscsit_dataout_pre_datapduinorder_yes(cmd, buf) :
722 		iscsit_dataout_pre_datapduinorder_no(cmd, buf);
723 }
724 
725 /*
726  *	Called from iscsit_handle_data_out() after DataOUT Payload is received
727  *	and CRC computed.
728  */
729 int iscsit_check_post_dataout(
730 	struct iscsi_cmd *cmd,
731 	unsigned char *buf,
732 	u8 data_crc_failed)
733 {
734 	struct iscsi_conn *conn = cmd->conn;
735 
736 	cmd->dataout_timeout_retries = 0;
737 
738 	if (!data_crc_failed)
739 		return iscsit_dataout_post_crc_passed(cmd, buf);
740 	else {
741 		if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
742 			pr_err("Unable to recover from DataOUT CRC"
743 				" failure while ERL=0, closing session.\n");
744 			iscsit_reject_cmd(cmd, ISCSI_REASON_DATA_DIGEST_ERROR,
745 					  buf);
746 			return DATAOUT_CANNOT_RECOVER;
747 		}
748 
749 		iscsit_reject_cmd(cmd, ISCSI_REASON_DATA_DIGEST_ERROR, buf);
750 		return iscsit_dataout_post_crc_failed(cmd, buf);
751 	}
752 }
753 
754 static void iscsit_handle_time2retain_timeout(unsigned long data)
755 {
756 	struct iscsi_session *sess = (struct iscsi_session *) data;
757 	struct iscsi_portal_group *tpg = sess->tpg;
758 	struct se_portal_group *se_tpg = &tpg->tpg_se_tpg;
759 
760 	spin_lock_bh(&se_tpg->session_lock);
761 	if (sess->time2retain_timer_flags & ISCSI_TF_STOP) {
762 		spin_unlock_bh(&se_tpg->session_lock);
763 		return;
764 	}
765 	if (atomic_read(&sess->session_reinstatement)) {
766 		pr_err("Exiting Time2Retain handler because"
767 				" session_reinstatement=1\n");
768 		spin_unlock_bh(&se_tpg->session_lock);
769 		return;
770 	}
771 	sess->time2retain_timer_flags |= ISCSI_TF_EXPIRED;
772 
773 	pr_err("Time2Retain timer expired for SID: %u, cleaning up"
774 			" iSCSI session.\n", sess->sid);
775 	{
776 	struct iscsi_tiqn *tiqn = tpg->tpg_tiqn;
777 
778 	if (tiqn) {
779 		spin_lock(&tiqn->sess_err_stats.lock);
780 		strcpy(tiqn->sess_err_stats.last_sess_fail_rem_name,
781 			(void *)sess->sess_ops->InitiatorName);
782 		tiqn->sess_err_stats.last_sess_failure_type =
783 				ISCSI_SESS_ERR_CXN_TIMEOUT;
784 		tiqn->sess_err_stats.cxn_timeout_errors++;
785 		atomic_long_inc(&sess->conn_timeout_errors);
786 		spin_unlock(&tiqn->sess_err_stats.lock);
787 	}
788 	}
789 
790 	spin_unlock_bh(&se_tpg->session_lock);
791 	target_put_session(sess->se_sess);
792 }
793 
794 void iscsit_start_time2retain_handler(struct iscsi_session *sess)
795 {
796 	int tpg_active;
797 	/*
798 	 * Only start Time2Retain timer when the associated TPG is still in
799 	 * an ACTIVE (eg: not disabled or shutdown) state.
800 	 */
801 	spin_lock(&sess->tpg->tpg_state_lock);
802 	tpg_active = (sess->tpg->tpg_state == TPG_STATE_ACTIVE);
803 	spin_unlock(&sess->tpg->tpg_state_lock);
804 
805 	if (!tpg_active)
806 		return;
807 
808 	if (sess->time2retain_timer_flags & ISCSI_TF_RUNNING)
809 		return;
810 
811 	pr_debug("Starting Time2Retain timer for %u seconds on"
812 		" SID: %u\n", sess->sess_ops->DefaultTime2Retain, sess->sid);
813 
814 	init_timer(&sess->time2retain_timer);
815 	sess->time2retain_timer.expires =
816 		(get_jiffies_64() + sess->sess_ops->DefaultTime2Retain * HZ);
817 	sess->time2retain_timer.data = (unsigned long)sess;
818 	sess->time2retain_timer.function = iscsit_handle_time2retain_timeout;
819 	sess->time2retain_timer_flags &= ~ISCSI_TF_STOP;
820 	sess->time2retain_timer_flags |= ISCSI_TF_RUNNING;
821 	add_timer(&sess->time2retain_timer);
822 }
823 
824 /*
825  *	Called with spin_lock_bh(&struct se_portal_group->session_lock) held
826  */
827 int iscsit_stop_time2retain_timer(struct iscsi_session *sess)
828 {
829 	struct iscsi_portal_group *tpg = sess->tpg;
830 	struct se_portal_group *se_tpg = &tpg->tpg_se_tpg;
831 
832 	if (sess->time2retain_timer_flags & ISCSI_TF_EXPIRED)
833 		return -1;
834 
835 	if (!(sess->time2retain_timer_flags & ISCSI_TF_RUNNING))
836 		return 0;
837 
838 	sess->time2retain_timer_flags |= ISCSI_TF_STOP;
839 	spin_unlock(&se_tpg->session_lock);
840 
841 	del_timer_sync(&sess->time2retain_timer);
842 
843 	spin_lock(&se_tpg->session_lock);
844 	sess->time2retain_timer_flags &= ~ISCSI_TF_RUNNING;
845 	pr_debug("Stopped Time2Retain Timer for SID: %u\n",
846 			sess->sid);
847 	return 0;
848 }
849 
850 void iscsit_connection_reinstatement_rcfr(struct iscsi_conn *conn)
851 {
852 	spin_lock_bh(&conn->state_lock);
853 	if (atomic_read(&conn->connection_exit)) {
854 		spin_unlock_bh(&conn->state_lock);
855 		goto sleep;
856 	}
857 
858 	if (atomic_read(&conn->transport_failed)) {
859 		spin_unlock_bh(&conn->state_lock);
860 		goto sleep;
861 	}
862 	spin_unlock_bh(&conn->state_lock);
863 
864 	iscsi_thread_set_force_reinstatement(conn);
865 
866 sleep:
867 	wait_for_completion(&conn->conn_wait_rcfr_comp);
868 	complete(&conn->conn_post_wait_comp);
869 }
870 
871 void iscsit_cause_connection_reinstatement(struct iscsi_conn *conn, int sleep)
872 {
873 	spin_lock_bh(&conn->state_lock);
874 	if (atomic_read(&conn->connection_exit)) {
875 		spin_unlock_bh(&conn->state_lock);
876 		return;
877 	}
878 
879 	if (atomic_read(&conn->transport_failed)) {
880 		spin_unlock_bh(&conn->state_lock);
881 		return;
882 	}
883 
884 	if (atomic_read(&conn->connection_reinstatement)) {
885 		spin_unlock_bh(&conn->state_lock);
886 		return;
887 	}
888 
889 	if (iscsi_thread_set_force_reinstatement(conn) < 0) {
890 		spin_unlock_bh(&conn->state_lock);
891 		return;
892 	}
893 
894 	atomic_set(&conn->connection_reinstatement, 1);
895 	if (!sleep) {
896 		spin_unlock_bh(&conn->state_lock);
897 		return;
898 	}
899 
900 	atomic_set(&conn->sleep_on_conn_wait_comp, 1);
901 	spin_unlock_bh(&conn->state_lock);
902 
903 	wait_for_completion(&conn->conn_wait_comp);
904 	complete(&conn->conn_post_wait_comp);
905 }
906 EXPORT_SYMBOL(iscsit_cause_connection_reinstatement);
907 
908 void iscsit_fall_back_to_erl0(struct iscsi_session *sess)
909 {
910 	pr_debug("Falling back to ErrorRecoveryLevel=0 for SID:"
911 			" %u\n", sess->sid);
912 
913 	atomic_set(&sess->session_fall_back_to_erl0, 1);
914 }
915 
916 static void iscsit_handle_connection_cleanup(struct iscsi_conn *conn)
917 {
918 	struct iscsi_session *sess = conn->sess;
919 
920 	if ((sess->sess_ops->ErrorRecoveryLevel == 2) &&
921 	    !atomic_read(&sess->session_reinstatement) &&
922 	    !atomic_read(&sess->session_fall_back_to_erl0))
923 		iscsit_connection_recovery_transport_reset(conn);
924 	else {
925 		pr_debug("Performing cleanup for failed iSCSI"
926 			" Connection ID: %hu from %s\n", conn->cid,
927 			sess->sess_ops->InitiatorName);
928 		iscsit_close_connection(conn);
929 	}
930 }
931 
932 void iscsit_take_action_for_connection_exit(struct iscsi_conn *conn)
933 {
934 	spin_lock_bh(&conn->state_lock);
935 	if (atomic_read(&conn->connection_exit)) {
936 		spin_unlock_bh(&conn->state_lock);
937 		return;
938 	}
939 	atomic_set(&conn->connection_exit, 1);
940 
941 	if (conn->conn_state == TARG_CONN_STATE_IN_LOGOUT) {
942 		spin_unlock_bh(&conn->state_lock);
943 		if (conn->conn_transport->transport_type == ISCSI_TCP)
944 			iscsit_close_connection(conn);
945 		return;
946 	}
947 
948 	if (conn->conn_state == TARG_CONN_STATE_CLEANUP_WAIT) {
949 		spin_unlock_bh(&conn->state_lock);
950 		return;
951 	}
952 
953 	pr_debug("Moving to TARG_CONN_STATE_CLEANUP_WAIT.\n");
954 	conn->conn_state = TARG_CONN_STATE_CLEANUP_WAIT;
955 	spin_unlock_bh(&conn->state_lock);
956 
957 	iscsit_handle_connection_cleanup(conn);
958 }
959 
960 /*
961  *	This is the simple function that makes the magic of
962  *	sync and steering happen in the follow paradoxical order:
963  *
964  *	0) Receive conn->of_marker (bytes left until next OFMarker)
965  *	   bytes into an offload buffer.  When we pass the exact number
966  *	   of bytes in conn->of_marker, iscsit_dump_data_payload() and hence
967  *	   rx_data() will automatically receive the identical u32 marker
968  *	   values and store it in conn->of_marker_offset;
969  *	1) Now conn->of_marker_offset will contain the offset to the start
970  *	   of the next iSCSI PDU.  Dump these remaining bytes into another
971  *	   offload buffer.
972  *	2) We are done!
973  *	   Next byte in the TCP stream will contain the next iSCSI PDU!
974  *	   Cool Huh?!
975  */
976 int iscsit_recover_from_unknown_opcode(struct iscsi_conn *conn)
977 {
978 	/*
979 	 * Make sure the remaining bytes to next maker is a sane value.
980 	 */
981 	if (conn->of_marker > (conn->conn_ops->OFMarkInt * 4)) {
982 		pr_err("Remaining bytes to OFMarker: %u exceeds"
983 			" OFMarkInt bytes: %u.\n", conn->of_marker,
984 				conn->conn_ops->OFMarkInt * 4);
985 		return -1;
986 	}
987 
988 	pr_debug("Advancing %u bytes in TCP stream to get to the"
989 			" next OFMarker.\n", conn->of_marker);
990 
991 	if (iscsit_dump_data_payload(conn, conn->of_marker, 0) < 0)
992 		return -1;
993 
994 	/*
995 	 * Make sure the offset marker we retrived is a valid value.
996 	 */
997 	if (conn->of_marker_offset > (ISCSI_HDR_LEN + (ISCSI_CRC_LEN * 2) +
998 	    conn->conn_ops->MaxRecvDataSegmentLength)) {
999 		pr_err("OfMarker offset value: %u exceeds limit.\n",
1000 			conn->of_marker_offset);
1001 		return -1;
1002 	}
1003 
1004 	pr_debug("Discarding %u bytes of TCP stream to get to the"
1005 			" next iSCSI Opcode.\n", conn->of_marker_offset);
1006 
1007 	if (iscsit_dump_data_payload(conn, conn->of_marker_offset, 0) < 0)
1008 		return -1;
1009 
1010 	return 0;
1011 }
1012