1/*******************************************************************************
2 * Filename: target_core_ua.c
3 *
4 * This file contains logic for SPC-3 Unit Attention emulation
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 <scsi/scsi_proto.h>
29
30#include <target/target_core_base.h>
31#include <target/target_core_fabric.h>
32
33#include "target_core_internal.h"
34#include "target_core_alua.h"
35#include "target_core_pr.h"
36#include "target_core_ua.h"
37
38sense_reason_t
39target_scsi3_ua_check(struct se_cmd *cmd)
40{
41	struct se_dev_entry *deve;
42	struct se_session *sess = cmd->se_sess;
43	struct se_node_acl *nacl;
44
45	if (!sess)
46		return 0;
47
48	nacl = sess->se_node_acl;
49	if (!nacl)
50		return 0;
51
52	rcu_read_lock();
53	deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
54	if (!deve) {
55		rcu_read_unlock();
56		return 0;
57	}
58	if (!atomic_read(&deve->ua_count)) {
59		rcu_read_unlock();
60		return 0;
61	}
62	rcu_read_unlock();
63	/*
64	 * From sam4r14, section 5.14 Unit attention condition:
65	 *
66	 * a) if an INQUIRY command enters the enabled command state, the
67	 *    device server shall process the INQUIRY command and shall neither
68	 *    report nor clear any unit attention condition;
69	 * b) if a REPORT LUNS command enters the enabled command state, the
70	 *    device server shall process the REPORT LUNS command and shall not
71	 *    report any unit attention condition;
72	 * e) if a REQUEST SENSE command enters the enabled command state while
73	 *    a unit attention condition exists for the SCSI initiator port
74	 *    associated with the I_T nexus on which the REQUEST SENSE command
75	 *    was received, then the device server shall process the command
76	 *    and either:
77	 */
78	switch (cmd->t_task_cdb[0]) {
79	case INQUIRY:
80	case REPORT_LUNS:
81	case REQUEST_SENSE:
82		return 0;
83	default:
84		return TCM_CHECK_CONDITION_UNIT_ATTENTION;
85	}
86}
87
88int core_scsi3_ua_allocate(
89	struct se_dev_entry *deve,
90	u8 asc,
91	u8 ascq)
92{
93	struct se_ua *ua, *ua_p, *ua_tmp;
94
95	ua = kmem_cache_zalloc(se_ua_cache, GFP_ATOMIC);
96	if (!ua) {
97		pr_err("Unable to allocate struct se_ua\n");
98		return -ENOMEM;
99	}
100	INIT_LIST_HEAD(&ua->ua_nacl_list);
101
102	ua->ua_asc = asc;
103	ua->ua_ascq = ascq;
104
105	spin_lock(&deve->ua_lock);
106	list_for_each_entry_safe(ua_p, ua_tmp, &deve->ua_list, ua_nacl_list) {
107		/*
108		 * Do not report the same UNIT ATTENTION twice..
109		 */
110		if ((ua_p->ua_asc == asc) && (ua_p->ua_ascq == ascq)) {
111			spin_unlock(&deve->ua_lock);
112			kmem_cache_free(se_ua_cache, ua);
113			return 0;
114		}
115		/*
116		 * Attach the highest priority Unit Attention to
117		 * the head of the list following sam4r14,
118		 * Section 5.14 Unit Attention Condition:
119		 *
120		 * POWER ON, RESET, OR BUS DEVICE RESET OCCURRED highest
121		 * POWER ON OCCURRED or
122		 * DEVICE INTERNAL RESET
123		 * SCSI BUS RESET OCCURRED or
124		 * MICROCODE HAS BEEN CHANGED or
125		 * protocol specific
126		 * BUS DEVICE RESET FUNCTION OCCURRED
127		 * I_T NEXUS LOSS OCCURRED
128		 * COMMANDS CLEARED BY POWER LOSS NOTIFICATION
129		 * all others                                    Lowest
130		 *
131		 * Each of the ASCQ codes listed above are defined in
132		 * the 29h ASC family, see spc4r17 Table D.1
133		 */
134		if (ua_p->ua_asc == 0x29) {
135			if ((asc == 0x29) && (ascq > ua_p->ua_ascq))
136				list_add(&ua->ua_nacl_list,
137						&deve->ua_list);
138			else
139				list_add_tail(&ua->ua_nacl_list,
140						&deve->ua_list);
141		} else if (ua_p->ua_asc == 0x2a) {
142			/*
143			 * Incoming Family 29h ASCQ codes will override
144			 * Family 2AHh ASCQ codes for Unit Attention condition.
145			 */
146			if ((asc == 0x29) || (ascq > ua_p->ua_asc))
147				list_add(&ua->ua_nacl_list,
148					&deve->ua_list);
149			else
150				list_add_tail(&ua->ua_nacl_list,
151						&deve->ua_list);
152		} else
153			list_add_tail(&ua->ua_nacl_list,
154				&deve->ua_list);
155		spin_unlock(&deve->ua_lock);
156
157		atomic_inc_mb(&deve->ua_count);
158		return 0;
159	}
160	list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
161	spin_unlock(&deve->ua_lock);
162
163	pr_debug("Allocated UNIT ATTENTION, mapped LUN: %llu, ASC:"
164		" 0x%02x, ASCQ: 0x%02x\n", deve->mapped_lun,
165		asc, ascq);
166
167	atomic_inc_mb(&deve->ua_count);
168	return 0;
169}
170
171void target_ua_allocate_lun(struct se_node_acl *nacl,
172			    u32 unpacked_lun, u8 asc, u8 ascq)
173{
174	struct se_dev_entry *deve;
175
176	if (!nacl)
177		return;
178
179	rcu_read_lock();
180	deve = target_nacl_find_deve(nacl, unpacked_lun);
181	if (!deve) {
182		rcu_read_unlock();
183		return;
184	}
185
186	core_scsi3_ua_allocate(deve, asc, ascq);
187	rcu_read_unlock();
188}
189
190void core_scsi3_ua_release_all(
191	struct se_dev_entry *deve)
192{
193	struct se_ua *ua, *ua_p;
194
195	spin_lock(&deve->ua_lock);
196	list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
197		list_del(&ua->ua_nacl_list);
198		kmem_cache_free(se_ua_cache, ua);
199
200		atomic_dec_mb(&deve->ua_count);
201	}
202	spin_unlock(&deve->ua_lock);
203}
204
205void core_scsi3_ua_for_check_condition(
206	struct se_cmd *cmd,
207	u8 *asc,
208	u8 *ascq)
209{
210	struct se_device *dev = cmd->se_dev;
211	struct se_dev_entry *deve;
212	struct se_session *sess = cmd->se_sess;
213	struct se_node_acl *nacl;
214	struct se_ua *ua = NULL, *ua_p;
215	int head = 1;
216
217	if (!sess)
218		return;
219
220	nacl = sess->se_node_acl;
221	if (!nacl)
222		return;
223
224	rcu_read_lock();
225	deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
226	if (!deve) {
227		rcu_read_unlock();
228		return;
229	}
230	if (!atomic_read(&deve->ua_count)) {
231		rcu_read_unlock();
232		return;
233	}
234	/*
235	 * The highest priority Unit Attentions are placed at the head of the
236	 * struct se_dev_entry->ua_list, and will be returned in CHECK_CONDITION +
237	 * sense data for the received CDB.
238	 */
239	spin_lock(&deve->ua_lock);
240	list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
241		/*
242		 * For ua_intlck_ctrl code not equal to 00b, only report the
243		 * highest priority UNIT_ATTENTION and ASC/ASCQ without
244		 * clearing it.
245		 */
246		if (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) {
247			*asc = ua->ua_asc;
248			*ascq = ua->ua_ascq;
249			break;
250		}
251		/*
252		 * Otherwise for the default 00b, release the UNIT ATTENTION
253		 * condition.  Return the ASC/ASCQ of the highest priority UA
254		 * (head of the list) in the outgoing CHECK_CONDITION + sense.
255		 */
256		if (head) {
257			*asc = ua->ua_asc;
258			*ascq = ua->ua_ascq;
259			head = 0;
260		}
261		list_del(&ua->ua_nacl_list);
262		kmem_cache_free(se_ua_cache, ua);
263
264		atomic_dec_mb(&deve->ua_count);
265	}
266	spin_unlock(&deve->ua_lock);
267	rcu_read_unlock();
268
269	pr_debug("[%s]: %s UNIT ATTENTION condition with"
270		" INTLCK_CTRL: %d, mapped LUN: %llu, got CDB: 0x%02x"
271		" reported ASC: 0x%02x, ASCQ: 0x%02x\n",
272		nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
273		(dev->dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
274		"Releasing", dev->dev_attrib.emulate_ua_intlck_ctrl,
275		cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);
276}
277
278int core_scsi3_ua_clear_for_request_sense(
279	struct se_cmd *cmd,
280	u8 *asc,
281	u8 *ascq)
282{
283	struct se_dev_entry *deve;
284	struct se_session *sess = cmd->se_sess;
285	struct se_node_acl *nacl;
286	struct se_ua *ua = NULL, *ua_p;
287	int head = 1;
288
289	if (!sess)
290		return -EINVAL;
291
292	nacl = sess->se_node_acl;
293	if (!nacl)
294		return -EINVAL;
295
296	rcu_read_lock();
297	deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
298	if (!deve) {
299		rcu_read_unlock();
300		return -EINVAL;
301	}
302	if (!atomic_read(&deve->ua_count)) {
303		rcu_read_unlock();
304		return -EPERM;
305	}
306	/*
307	 * The highest priority Unit Attentions are placed at the head of the
308	 * struct se_dev_entry->ua_list.  The First (and hence highest priority)
309	 * ASC/ASCQ will be returned in REQUEST_SENSE payload data for the
310	 * matching struct se_lun.
311	 *
312	 * Once the returning ASC/ASCQ values are set, we go ahead and
313	 * release all of the Unit Attention conditions for the associated
314	 * struct se_lun.
315	 */
316	spin_lock(&deve->ua_lock);
317	list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
318		if (head) {
319			*asc = ua->ua_asc;
320			*ascq = ua->ua_ascq;
321			head = 0;
322		}
323		list_del(&ua->ua_nacl_list);
324		kmem_cache_free(se_ua_cache, ua);
325
326		atomic_dec_mb(&deve->ua_count);
327	}
328	spin_unlock(&deve->ua_lock);
329	rcu_read_unlock();
330
331	pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
332		" LUN: %llu, got REQUEST_SENSE reported ASC: 0x%02x,"
333		" ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
334		cmd->orig_fe_lun, *asc, *ascq);
335
336	return (head) ? -EPERM : 0;
337}
338