1/*******************************************************************************
2 * Filename:  target_core_tmr.c
3 *
4 * This file contains SPC-3 task management infrastructure
5 *
6 * (c) Copyright 2009-2013 Datera, Inc.
7 *
8 * Nicholas A. Bellinger <nab@kernel.org>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23 *
24 ******************************************************************************/
25
26#include <linux/slab.h>
27#include <linux/spinlock.h>
28#include <linux/list.h>
29#include <linux/export.h>
30#include <scsi/scsi.h>
31#include <scsi/scsi_cmnd.h>
32
33#include <target/target_core_base.h>
34#include <target/target_core_backend.h>
35#include <target/target_core_fabric.h>
36#include <target/target_core_configfs.h>
37
38#include "target_core_internal.h"
39#include "target_core_alua.h"
40#include "target_core_pr.h"
41
42int core_tmr_alloc_req(
43	struct se_cmd *se_cmd,
44	void *fabric_tmr_ptr,
45	u8 function,
46	gfp_t gfp_flags)
47{
48	struct se_tmr_req *tmr;
49
50	tmr = kzalloc(sizeof(struct se_tmr_req), gfp_flags);
51	if (!tmr) {
52		pr_err("Unable to allocate struct se_tmr_req\n");
53		return -ENOMEM;
54	}
55
56	se_cmd->se_cmd_flags |= SCF_SCSI_TMR_CDB;
57	se_cmd->se_tmr_req = tmr;
58	tmr->task_cmd = se_cmd;
59	tmr->fabric_tmr_ptr = fabric_tmr_ptr;
60	tmr->function = function;
61	INIT_LIST_HEAD(&tmr->tmr_list);
62
63	return 0;
64}
65EXPORT_SYMBOL(core_tmr_alloc_req);
66
67void core_tmr_release_req(struct se_tmr_req *tmr)
68{
69	struct se_device *dev = tmr->tmr_dev;
70	unsigned long flags;
71
72	if (dev) {
73		spin_lock_irqsave(&dev->se_tmr_lock, flags);
74		list_del(&tmr->tmr_list);
75		spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
76	}
77
78	kfree(tmr);
79}
80
81static void core_tmr_handle_tas_abort(
82	struct se_node_acl *tmr_nacl,
83	struct se_cmd *cmd,
84	int tas)
85{
86	bool remove = true;
87	/*
88	 * TASK ABORTED status (TAS) bit support
89	 */
90	if ((tmr_nacl && (tmr_nacl != cmd->se_sess->se_node_acl)) && tas) {
91		remove = false;
92		transport_send_task_abort(cmd);
93	}
94
95	transport_cmd_finish_abort(cmd, remove);
96}
97
98static int target_check_cdb_and_preempt(struct list_head *list,
99		struct se_cmd *cmd)
100{
101	struct t10_pr_registration *reg;
102
103	if (!list)
104		return 0;
105	list_for_each_entry(reg, list, pr_reg_abort_list) {
106		if (reg->pr_res_key == cmd->pr_res_key)
107			return 0;
108	}
109
110	return 1;
111}
112
113void core_tmr_abort_task(
114	struct se_device *dev,
115	struct se_tmr_req *tmr,
116	struct se_session *se_sess)
117{
118	struct se_cmd *se_cmd;
119	unsigned long flags;
120	int ref_tag;
121
122	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
123	list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
124
125		if (dev != se_cmd->se_dev)
126			continue;
127
128		/* skip se_cmd associated with tmr */
129		if (tmr->task_cmd == se_cmd)
130			continue;
131
132		ref_tag = se_cmd->se_tfo->get_task_tag(se_cmd);
133		if (tmr->ref_task_tag != ref_tag)
134			continue;
135
136		printk("ABORT_TASK: Found referenced %s task_tag: %u\n",
137			se_cmd->se_tfo->get_fabric_name(), ref_tag);
138
139		spin_lock(&se_cmd->t_state_lock);
140		if (se_cmd->transport_state & CMD_T_COMPLETE) {
141			printk("ABORT_TASK: ref_tag: %u already complete, skipping\n", ref_tag);
142			spin_unlock(&se_cmd->t_state_lock);
143			spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
144			goto out;
145		}
146		se_cmd->transport_state |= CMD_T_ABORTED;
147		spin_unlock(&se_cmd->t_state_lock);
148
149		list_del_init(&se_cmd->se_cmd_list);
150		kref_get(&se_cmd->cmd_kref);
151		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
152
153		cancel_work_sync(&se_cmd->work);
154		transport_wait_for_tasks(se_cmd);
155
156		target_put_sess_cmd(se_sess, se_cmd);
157		transport_cmd_finish_abort(se_cmd, true);
158
159		printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
160				" ref_tag: %d\n", ref_tag);
161		tmr->response = TMR_FUNCTION_COMPLETE;
162		return;
163	}
164	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
165
166out:
167	printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %d\n",
168			tmr->ref_task_tag);
169	tmr->response = TMR_TASK_DOES_NOT_EXIST;
170}
171
172static void core_tmr_drain_tmr_list(
173	struct se_device *dev,
174	struct se_tmr_req *tmr,
175	struct list_head *preempt_and_abort_list)
176{
177	LIST_HEAD(drain_tmr_list);
178	struct se_tmr_req *tmr_p, *tmr_pp;
179	struct se_cmd *cmd;
180	unsigned long flags;
181	/*
182	 * Release all pending and outgoing TMRs aside from the received
183	 * LUN_RESET tmr..
184	 */
185	spin_lock_irqsave(&dev->se_tmr_lock, flags);
186	list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
187		/*
188		 * Allow the received TMR to return with FUNCTION_COMPLETE.
189		 */
190		if (tmr_p == tmr)
191			continue;
192
193		cmd = tmr_p->task_cmd;
194		if (!cmd) {
195			pr_err("Unable to locate struct se_cmd for TMR\n");
196			continue;
197		}
198		/*
199		 * If this function was called with a valid pr_res_key
200		 * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
201		 * skip non regisration key matching TMRs.
202		 */
203		if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
204			continue;
205
206		spin_lock(&cmd->t_state_lock);
207		if (!(cmd->transport_state & CMD_T_ACTIVE)) {
208			spin_unlock(&cmd->t_state_lock);
209			continue;
210		}
211		if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
212			spin_unlock(&cmd->t_state_lock);
213			continue;
214		}
215		spin_unlock(&cmd->t_state_lock);
216
217		list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
218	}
219	spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
220
221	list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
222		list_del_init(&tmr_p->tmr_list);
223		cmd = tmr_p->task_cmd;
224
225		pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
226			" Response: 0x%02x, t_state: %d\n",
227			(preempt_and_abort_list) ? "Preempt" : "", tmr_p,
228			tmr_p->function, tmr_p->response, cmd->t_state);
229
230		transport_cmd_finish_abort(cmd, 1);
231	}
232}
233
234static void core_tmr_drain_state_list(
235	struct se_device *dev,
236	struct se_cmd *prout_cmd,
237	struct se_node_acl *tmr_nacl,
238	int tas,
239	struct list_head *preempt_and_abort_list)
240{
241	LIST_HEAD(drain_task_list);
242	struct se_cmd *cmd, *next;
243	unsigned long flags;
244
245	/*
246	 * Complete outstanding commands with TASK_ABORTED SAM status.
247	 *
248	 * This is following sam4r17, section 5.6 Aborting commands, Table 38
249	 * for TMR LUN_RESET:
250	 *
251	 * a) "Yes" indicates that each command that is aborted on an I_T nexus
252	 * other than the one that caused the SCSI device condition is
253	 * completed with TASK ABORTED status, if the TAS bit is set to one in
254	 * the Control mode page (see SPC-4). "No" indicates that no status is
255	 * returned for aborted commands.
256	 *
257	 * d) If the logical unit reset is caused by a particular I_T nexus
258	 * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
259	 * (TASK_ABORTED status) applies.
260	 *
261	 * Otherwise (e.g., if triggered by a hard reset), "no"
262	 * (no TASK_ABORTED SAM status) applies.
263	 *
264	 * Note that this seems to be independent of TAS (Task Aborted Status)
265	 * in the Control Mode Page.
266	 */
267	spin_lock_irqsave(&dev->execute_task_lock, flags);
268	list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
269		/*
270		 * For PREEMPT_AND_ABORT usage, only process commands
271		 * with a matching reservation key.
272		 */
273		if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
274			continue;
275
276		/*
277		 * Not aborting PROUT PREEMPT_AND_ABORT CDB..
278		 */
279		if (prout_cmd == cmd)
280			continue;
281
282		list_move_tail(&cmd->state_list, &drain_task_list);
283		cmd->state_active = false;
284	}
285	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
286
287	while (!list_empty(&drain_task_list)) {
288		cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
289		list_del(&cmd->state_list);
290
291		pr_debug("LUN_RESET: %s cmd: %p"
292			" ITT/CmdSN: 0x%08x/0x%08x, i_state: %d, t_state: %d"
293			"cdb: 0x%02x\n",
294			(preempt_and_abort_list) ? "Preempt" : "", cmd,
295			cmd->se_tfo->get_task_tag(cmd), 0,
296			cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
297			cmd->t_task_cdb[0]);
298		pr_debug("LUN_RESET: ITT[0x%08x] - pr_res_key: 0x%016Lx"
299			" -- CMD_T_ACTIVE: %d"
300			" CMD_T_STOP: %d CMD_T_SENT: %d\n",
301			cmd->se_tfo->get_task_tag(cmd), cmd->pr_res_key,
302			(cmd->transport_state & CMD_T_ACTIVE) != 0,
303			(cmd->transport_state & CMD_T_STOP) != 0,
304			(cmd->transport_state & CMD_T_SENT) != 0);
305
306		/*
307		 * If the command may be queued onto a workqueue cancel it now.
308		 *
309		 * This is equivalent to removal from the execute queue in the
310		 * loop above, but we do it down here given that
311		 * cancel_work_sync may block.
312		 */
313		if (cmd->t_state == TRANSPORT_COMPLETE)
314			cancel_work_sync(&cmd->work);
315
316		spin_lock_irqsave(&cmd->t_state_lock, flags);
317		target_stop_cmd(cmd, &flags);
318
319		cmd->transport_state |= CMD_T_ABORTED;
320		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
321
322		core_tmr_handle_tas_abort(tmr_nacl, cmd, tas);
323	}
324}
325
326int core_tmr_lun_reset(
327        struct se_device *dev,
328        struct se_tmr_req *tmr,
329        struct list_head *preempt_and_abort_list,
330        struct se_cmd *prout_cmd)
331{
332	struct se_node_acl *tmr_nacl = NULL;
333	struct se_portal_group *tmr_tpg = NULL;
334	int tas;
335        /*
336	 * TASK_ABORTED status bit, this is configurable via ConfigFS
337	 * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
338	 *
339	 * A task aborted status (TAS) bit set to zero specifies that aborted
340	 * tasks shall be terminated by the device server without any response
341	 * to the application client. A TAS bit set to one specifies that tasks
342	 * aborted by the actions of an I_T nexus other than the I_T nexus on
343	 * which the command was received shall be completed with TASK ABORTED
344	 * status (see SAM-4).
345	 */
346	tas = dev->dev_attrib.emulate_tas;
347	/*
348	 * Determine if this se_tmr is coming from a $FABRIC_MOD
349	 * or struct se_device passthrough..
350	 */
351	if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
352		tmr_nacl = tmr->task_cmd->se_sess->se_node_acl;
353		tmr_tpg = tmr->task_cmd->se_sess->se_tpg;
354		if (tmr_nacl && tmr_tpg) {
355			pr_debug("LUN_RESET: TMR caller fabric: %s"
356				" initiator port %s\n",
357				tmr_tpg->se_tpg_tfo->get_fabric_name(),
358				tmr_nacl->initiatorname);
359		}
360	}
361	pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
362		(preempt_and_abort_list) ? "Preempt" : "TMR",
363		dev->transport->name, tas);
364
365	core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
366	core_tmr_drain_state_list(dev, prout_cmd, tmr_nacl, tas,
367				preempt_and_abort_list);
368
369	/*
370	 * Clear any legacy SPC-2 reservation when called during
371	 * LOGICAL UNIT RESET
372	 */
373	if (!preempt_and_abort_list &&
374	     (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
375		spin_lock(&dev->dev_reservation_lock);
376		dev->dev_reserved_node_acl = NULL;
377		dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
378		spin_unlock(&dev->dev_reservation_lock);
379		pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
380	}
381
382	atomic_long_inc(&dev->num_resets);
383
384	pr_debug("LUN_RESET: %s for [%s] Complete\n",
385			(preempt_and_abort_list) ? "Preempt" : "TMR",
386			dev->transport->name);
387	return 0;
388}
389
390