summaryrefslogtreecommitdiffstats
path: root/drivers/target/target_core_tmr.c
blob: 3a1bb799a9ab304860777b22c3948a11d5f0194b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
/*******************************************************************************
 * Filename:  target_core_tmr.c
 *
 * This file contains SPC-3 task management infrastructure
 *
 * (c) Copyright 2009-2013 Datera, Inc.
 *
 * Nicholas A. Bellinger <nab@kernel.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 ******************************************************************************/

#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/export.h>

#include <target/target_core_base.h>
#include <target/target_core_backend.h>
#include <target/target_core_fabric.h>

#include "target_core_internal.h"
#include "target_core_alua.h"
#include "target_core_pr.h"

int core_tmr_alloc_req(
	struct se_cmd *se_cmd,
	void *fabric_tmr_ptr,
	u8 function,
	gfp_t gfp_flags)
{
	struct se_tmr_req *tmr;

	tmr = kzalloc(sizeof(struct se_tmr_req), gfp_flags);
	if (!tmr) {
		pr_err("Unable to allocate struct se_tmr_req\n");
		return -ENOMEM;
	}

	se_cmd->se_cmd_flags |= SCF_SCSI_TMR_CDB;
	se_cmd->se_tmr_req = tmr;
	tmr->task_cmd = se_cmd;
	tmr->fabric_tmr_ptr = fabric_tmr_ptr;
	tmr->function = function;
	INIT_LIST_HEAD(&tmr->tmr_list);

	return 0;
}
EXPORT_SYMBOL(core_tmr_alloc_req);

void core_tmr_release_req(struct se_tmr_req *tmr)
{
	struct se_device *dev = tmr->tmr_dev;
	unsigned long flags;

	if (dev) {
		spin_lock_irqsave(&dev->se_tmr_lock, flags);
		list_del_init(&tmr->tmr_list);
		spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
	}

	kfree(tmr);
}

static int target_check_cdb_and_preempt(struct list_head *list,
		struct se_cmd *cmd)
{
	struct t10_pr_registration *reg;

	if (!list)
		return 0;
	list_for_each_entry(reg, list, pr_reg_abort_list) {
		if (reg->pr_res_key == cmd->pr_res_key)
			return 0;
	}

	return 1;
}

static bool __target_check_io_state(struct se_cmd *se_cmd,
				    struct se_session *tmr_sess, int tas)
{
	struct se_session *sess = se_cmd->se_sess;

	assert_spin_locked(&sess->sess_cmd_lock);
	WARN_ON_ONCE(!irqs_disabled());
	/*
	 * If command already reached CMD_T_COMPLETE state within
	 * target_complete_cmd() or CMD_T_FABRIC_STOP due to shutdown,
	 * this se_cmd has been passed to fabric driver and will
	 * not be aborted.
	 *
	 * Otherwise, obtain a local se_cmd->cmd_kref now for TMR
	 * ABORT_TASK + LUN_RESET for CMD_T_ABORTED processing as
	 * long as se_cmd->cmd_kref is still active unless zero.
	 */
	spin_lock(&se_cmd->t_state_lock);
	if (se_cmd->transport_state & (CMD_T_COMPLETE | CMD_T_FABRIC_STOP)) {
		pr_debug("Attempted to abort io tag: %llu already complete or"
			" fabric stop, skipping\n", se_cmd->tag);
		spin_unlock(&se_cmd->t_state_lock);
		return false;
	}
	se_cmd->transport_state |= CMD_T_ABORTED;

	if ((tmr_sess != se_cmd->se_sess) && tas)
		se_cmd->transport_state |= CMD_T_TAS;

	spin_unlock(&se_cmd->t_state_lock);

	return kref_get_unless_zero(&se_cmd->cmd_kref);
}

void core_tmr_abort_task(
	struct se_device *dev,
	struct se_tmr_req *tmr,
	struct se_session *se_sess)
{
	struct se_cmd *se_cmd;
	unsigned long flags;
	u64 ref_tag;

	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
	list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {

		if (dev != se_cmd->se_dev)
			continue;

		/* skip task management functions, including tmr->task_cmd */
		if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
			continue;

		ref_tag = se_cmd->tag;
		if (tmr->ref_task_tag != ref_tag)
			continue;

		printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",
			se_cmd->se_tfo->fabric_name, ref_tag);

		if (!__target_check_io_state(se_cmd, se_sess,
					     dev->dev_attrib.emulate_tas))
			continue;

		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);

		/*
		 * Ensure that this ABORT request is visible to the LU RESET
		 * code.
		 */
		if (!tmr->tmr_dev)
			WARN_ON_ONCE(transport_lookup_tmr_lun(tmr->task_cmd,
						se_cmd->orig_fe_lun) < 0);

		target_put_cmd_and_wait(se_cmd);

		printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
				" ref_tag: %llu\n", ref_tag);
		tmr->response = TMR_FUNCTION_COMPLETE;
		atomic_long_inc(&dev->aborts_complete);
		return;
	}
	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);

	printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
			tmr->ref_task_tag);
	tmr->response = TMR_TASK_DOES_NOT_EXIST;
	atomic_long_inc(&dev->aborts_no_task);
}

static void core_tmr_drain_tmr_list(
	struct se_device *dev,
	struct se_tmr_req *tmr,
	struct list_head *preempt_and_abort_list)
{
	LIST_HEAD(drain_tmr_list);
	struct se_session *sess;
	struct se_tmr_req *tmr_p, *tmr_pp;
	struct se_cmd *cmd;
	unsigned long flags;
	bool rc;
	/*
	 * Release all pending and outgoing TMRs aside from the received
	 * LUN_RESET tmr..
	 */
	spin_lock_irqsave(&dev->se_tmr_lock, flags);
	if (tmr)
		list_del_init(&tmr->tmr_list);
	list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
		cmd = tmr_p->task_cmd;
		if (!cmd) {
			pr_err("Unable to locate struct se_cmd for TMR\n");
			continue;
		}
		/*
		 * If this function was called with a valid pr_res_key
		 * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
		 * skip non registration key matching TMRs.
		 */
		if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
			continue;

		sess = cmd->se_sess;
		if (WARN_ON_ONCE(!sess))
			continue;

		spin_lock(&sess->sess_cmd_lock);
		rc = __target_check_io_state(cmd, sess, 0);
		spin_unlock(&sess->sess_cmd_lock);

		if (!rc) {
			printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
			continue;
		}

		list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
	}
	spin_unlock_irqrestore(&dev->se_tmr_lock, flags);

	list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
		list_del_init(&tmr_p->tmr_list);
		cmd = tmr_p->task_cmd;

		pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
			" Response: 0x%02x, t_state: %d\n",
			(preempt_and_abort_list) ? "Preempt" : "", tmr_p,
			tmr_p->function, tmr_p->response, cmd->t_state);

		target_put_cmd_and_wait(cmd);
	}
}

/**
 * core_tmr_drain_state_list() - abort SCSI commands associated with a device
 *
 * @dev:       Device for which to abort outstanding SCSI commands.
 * @prout_cmd: Pointer to the SCSI PREEMPT AND ABORT if this function is called
 *             to realize the PREEMPT AND ABORT functionality.
 * @tmr_sess:  Session through which the LUN RESET has been received.
 * @tas:       Task Aborted Status (TAS) bit from the SCSI control mode page.
 *             A quote from SPC-4, paragraph "7.5.10 Control mode page":
 *             "A task aborted status (TAS) bit set to zero specifies that
 *             aborted commands shall be terminated by the device server
 *             without any response to the application client. A TAS bit set
 *             to one specifies that commands aborted by the actions of an I_T
 *             nexus other than the I_T nexus on which the command was
 *             received shall be completed with TASK ABORTED status."
 * @preempt_and_abort_list: For the PREEMPT AND ABORT functionality, a list
 *             with registrations that will be preempted.
 */
static void core_tmr_drain_state_list(
	struct se_device *dev,
	struct se_cmd *prout_cmd,
	struct se_session *tmr_sess,
	int tas,
	struct list_head *preempt_and_abort_list)
{
	LIST_HEAD(drain_task_list);
	struct se_session *sess;
	struct se_cmd *cmd, *next;
	unsigned long flags;
	int rc;

	/*
	 * Complete outstanding commands with TASK_ABORTED SAM status.
	 *
	 * This is following sam4r17, section 5.6 Aborting commands, Table 38
	 * for TMR LUN_RESET:
	 *
	 * a) "Yes" indicates that each command that is aborted on an I_T nexus
	 * other than the one that caused the SCSI device condition is
	 * completed with TASK ABORTED status, if the TAS bit is set to one in
	 * the Control mode page (see SPC-4). "No" indicates that no status is
	 * returned for aborted commands.
	 *
	 * d) If the logical unit reset is caused by a particular I_T nexus
	 * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
	 * (TASK_ABORTED status) applies.
	 *
	 * Otherwise (e.g., if triggered by a hard reset), "no"
	 * (no TASK_ABORTED SAM status) applies.
	 *
	 * Note that this seems to be independent of TAS (Task Aborted Status)
	 * in the Control Mode Page.
	 */
	spin_lock_irqsave(&dev->execute_task_lock, flags);
	list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
		/*
		 * For PREEMPT_AND_ABORT usage, only process commands
		 * with a matching reservation key.
		 */
		if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
			continue;

		/*
		 * Not aborting PROUT PREEMPT_AND_ABORT CDB..
		 */
		if (prout_cmd == cmd)
			continue;

		sess = cmd->se_sess;
		if (WARN_ON_ONCE(!sess))
			continue;

		spin_lock(&sess->sess_cmd_lock);
		rc = __target_check_io_state(cmd, tmr_sess, tas);
		spin_unlock(&sess->sess_cmd_lock);
		if (!rc)
			continue;

		list_move_tail(&cmd->state_list, &drain_task_list);
		cmd->state_active = false;
	}
	spin_unlock_irqrestore(&dev->execute_task_lock, flags);

	while (!list_empty(&drain_task_list)) {
		cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
		list_del_init(&cmd->state_list);

		target_show_cmd("LUN_RESET: ", cmd);
		pr_debug("LUN_RESET: ITT[0x%08llx] - %s pr_res_key: 0x%016Lx\n",
			 cmd->tag, (preempt_and_abort_list) ? "preempt" : "",
			 cmd->pr_res_key);

		target_put_cmd_and_wait(cmd);
	}
}

int core_tmr_lun_reset(
        struct se_device *dev,
        struct se_tmr_req *tmr,
        struct list_head *preempt_and_abort_list,
        struct se_cmd *prout_cmd)
{
	struct se_node_acl *tmr_nacl = NULL;
	struct se_portal_group *tmr_tpg = NULL;
	struct se_session *tmr_sess = NULL;
	int tas;
        /*
	 * TASK_ABORTED status bit, this is configurable via ConfigFS
	 * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
	 *
	 * A task aborted status (TAS) bit set to zero specifies that aborted
	 * tasks shall be terminated by the device server without any response
	 * to the application client. A TAS bit set to one specifies that tasks
	 * aborted by the actions of an I_T nexus other than the I_T nexus on
	 * which the command was received shall be completed with TASK ABORTED
	 * status (see SAM-4).
	 */
	tas = dev->dev_attrib.emulate_tas;
	/*
	 * Determine if this se_tmr is coming from a $FABRIC_MOD
	 * or struct se_device passthrough..
	 */
	if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
		tmr_sess = tmr->task_cmd->se_sess;
		tmr_nacl = tmr_sess->se_node_acl;
		tmr_tpg = tmr_sess->se_tpg;
		if (tmr_nacl && tmr_tpg) {
			pr_debug("LUN_RESET: TMR caller fabric: %s"
				" initiator port %s\n",
				tmr_tpg->se_tpg_tfo->fabric_name,
				tmr_nacl->initiatorname);
		}
	}
	pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
		(preempt_and_abort_list) ? "Preempt" : "TMR",
		dev->transport->name, tas);

	core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
	core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
				preempt_and_abort_list);

	/*
	 * Clear any legacy SPC-2 reservation when called during
	 * LOGICAL UNIT RESET
	 */
	if (!preempt_and_abort_list &&
	     (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
		spin_lock(&dev->dev_reservation_lock);
		dev->dev_reserved_node_acl = NULL;
		dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
		spin_unlock(&dev->dev_reservation_lock);
		pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
	}

	atomic_long_inc(&dev->num_resets);

	pr_debug("LUN_RESET: %s for [%s] Complete\n",
			(preempt_and_abort_list) ? "Preempt" : "TMR",
			dev->transport->name);
	return 0;
}