1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*******************************************************************************
3 * Filename: target_core_ua.c
4 *
5 * This file contains logic for SPC-3 Unit Attention emulation
6 *
7 * (c) Copyright 2009-2013 Datera, Inc.
8 *
9 * Nicholas A. Bellinger <nab@kernel.org>
10 *
11 ******************************************************************************/
12
13 #include <linux/slab.h>
14 #include <linux/spinlock.h>
15 #include <scsi/scsi_proto.h>
16
17 #include <target/target_core_base.h>
18 #include <target/target_core_fabric.h>
19
20 #include "target_core_internal.h"
21 #include "target_core_alua.h"
22 #include "target_core_pr.h"
23 #include "target_core_ua.h"
24
25 sense_reason_t
26 target_scsi3_ua_check(struct se_cmd *cmd)
27 {
28 struct se_dev_entry *deve;
29 struct se_session *sess = cmd->se_sess;
30 struct se_node_acl *nacl;
31
32 if (!sess)
33 return 0;
34
35 nacl = sess->se_node_acl;
36 if (!nacl)
37 return 0;
38
39 rcu_read_lock();
40 deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
41 if (!deve) {
42 rcu_read_unlock();
43 return 0;
44 }
45 if (list_empty_careful(&deve->ua_list)) {
46 rcu_read_unlock();
47 return 0;
48 }
49 rcu_read_unlock();
50 /*
51 * From sam4r14, section 5.14 Unit attention condition:
52 *
53 * a) if an INQUIRY command enters the enabled command state, the
54 * device server shall process the INQUIRY command and shall neither
55 * report nor clear any unit attention condition;
56 * b) if a REPORT LUNS command enters the enabled command state, the
57 * device server shall process the REPORT LUNS command and shall not
58 * report any unit attention condition;
59 * e) if a REQUEST SENSE command enters the enabled command state while
60 * a unit attention condition exists for the SCSI initiator port
61 * associated with the I_T nexus on which the REQUEST SENSE command
62 * was received, then the device server shall process the command
63 * and either:
64 */
65 switch (cmd->t_task_cdb[0]) {
66 case INQUIRY:
67 case REPORT_LUNS:
68 case REQUEST_SENSE:
69 return 0;
70 default:
71 return TCM_CHECK_CONDITION_UNIT_ATTENTION;
72 }
73 }
74
75 int core_scsi3_ua_allocate(
76 struct se_dev_entry *deve,
77 u8 asc,
78 u8 ascq)
79 {
80 struct se_ua *ua, *ua_p, *ua_tmp;
81
82 ua = kmem_cache_zalloc(se_ua_cache, GFP_ATOMIC);
83 if (!ua) {
84 pr_err("Unable to allocate struct se_ua\n");
85 return -ENOMEM;
86 }
87 INIT_LIST_HEAD(&ua->ua_nacl_list);
88
89 ua->ua_asc = asc;
90 ua->ua_ascq = ascq;
91
92 spin_lock(&deve->ua_lock);
93 list_for_each_entry_safe(ua_p, ua_tmp, &deve->ua_list, ua_nacl_list) {
94 /*
95 * Do not report the same UNIT ATTENTION twice..
96 */
97 if ((ua_p->ua_asc == asc) && (ua_p->ua_ascq == ascq)) {
98 spin_unlock(&deve->ua_lock);
99 kmem_cache_free(se_ua_cache, ua);
100 return 0;
101 }
102 /*
103 * Attach the highest priority Unit Attention to
104 * the head of the list following sam4r14,
105 * Section 5.14 Unit Attention Condition:
106 *
107 * POWER ON, RESET, OR BUS DEVICE RESET OCCURRED highest
108 * POWER ON OCCURRED or
109 * DEVICE INTERNAL RESET
110 * SCSI BUS RESET OCCURRED or
111 * MICROCODE HAS BEEN CHANGED or
112 * protocol specific
113 * BUS DEVICE RESET FUNCTION OCCURRED
114 * I_T NEXUS LOSS OCCURRED
115 * COMMANDS CLEARED BY POWER LOSS NOTIFICATION
116 * all others Lowest
117 *
118 * Each of the ASCQ codes listed above are defined in
119 * the 29h ASC family, see spc4r17 Table D.1
120 */
121 if (ua_p->ua_asc == 0x29) {
122 if ((asc == 0x29) && (ascq > ua_p->ua_ascq))
123 list_add(&ua->ua_nacl_list,
124 &deve->ua_list);
125 else
126 list_add_tail(&ua->ua_nacl_list,
127 &deve->ua_list);
128 } else if (ua_p->ua_asc == 0x2a) {
129 /*
130 * Incoming Family 29h ASCQ codes will override
131 * Family 2AHh ASCQ codes for Unit Attention condition.
132 */
133 if ((asc == 0x29) || (ascq > ua_p->ua_asc))
134 list_add(&ua->ua_nacl_list,
135 &deve->ua_list);
136 else
137 list_add_tail(&ua->ua_nacl_list,
138 &deve->ua_list);
139 } else
140 list_add_tail(&ua->ua_nacl_list,
141 &deve->ua_list);
142 spin_unlock(&deve->ua_lock);
143
144 return 0;
145 }
146 list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
147 spin_unlock(&deve->ua_lock);
148
149 pr_debug("Allocated UNIT ATTENTION, mapped LUN: %llu, ASC:"
150 " 0x%02x, ASCQ: 0x%02x\n", deve->mapped_lun,
151 asc, ascq);
152
153 return 0;
154 }
155
156 void target_ua_allocate_lun(struct se_node_acl *nacl,
157 u32 unpacked_lun, u8 asc, u8 ascq)
158 {
159 struct se_dev_entry *deve;
160
161 if (!nacl)
162 return;
163
164 rcu_read_lock();
165 deve = target_nacl_find_deve(nacl, unpacked_lun);
166 if (!deve) {
167 rcu_read_unlock();
168 return;
169 }
170
171 core_scsi3_ua_allocate(deve, asc, ascq);
172 rcu_read_unlock();
173 }
174
175 void core_scsi3_ua_release_all(
176 struct se_dev_entry *deve)
177 {
178 struct se_ua *ua, *ua_p;
179
180 spin_lock(&deve->ua_lock);
181 list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
182 list_del(&ua->ua_nacl_list);
183 kmem_cache_free(se_ua_cache, ua);
184 }
185 spin_unlock(&deve->ua_lock);
186 }
187
188 /*
189 * Dequeue a unit attention from the unit attention list. This function
190 * returns true if the dequeuing succeeded and if *@key, *@asc and *@ascq have
191 * been set.
192 */
193 bool core_scsi3_ua_for_check_condition(struct se_cmd *cmd, u8 *key, u8 *asc,
194 u8 *ascq)
195 {
196 struct se_device *dev = cmd->se_dev;
197 struct se_dev_entry *deve;
198 struct se_session *sess = cmd->se_sess;
199 struct se_node_acl *nacl;
200 struct se_ua *ua = NULL, *ua_p;
201 int head = 1;
202
203 if (WARN_ON_ONCE(!sess))
204 return false;
205
206 nacl = sess->se_node_acl;
207 if (WARN_ON_ONCE(!nacl))
208 return false;
209
210 rcu_read_lock();
211 deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
212 if (!deve) {
213 rcu_read_unlock();
214 *key = ILLEGAL_REQUEST;
215 *asc = 0x25; /* LOGICAL UNIT NOT SUPPORTED */
216 *ascq = 0;
217 return true;
218 }
219 *key = UNIT_ATTENTION;
220 /*
221 * The highest priority Unit Attentions are placed at the head of the
222 * struct se_dev_entry->ua_list, and will be returned in CHECK_CONDITION +
223 * sense data for the received CDB.
224 */
225 spin_lock(&deve->ua_lock);
226 list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
227 /*
228 * For ua_intlck_ctrl code not equal to 00b, only report the
229 * highest priority UNIT_ATTENTION and ASC/ASCQ without
230 * clearing it.
231 */
232 if (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) {
233 *asc = ua->ua_asc;
234 *ascq = ua->ua_ascq;
235 break;
236 }
237 /*
238 * Otherwise for the default 00b, release the UNIT ATTENTION
239 * condition. Return the ASC/ASCQ of the highest priority UA
240 * (head of the list) in the outgoing CHECK_CONDITION + sense.
241 */
242 if (head) {
243 *asc = ua->ua_asc;
244 *ascq = ua->ua_ascq;
245 head = 0;
246 }
247 list_del(&ua->ua_nacl_list);
248 kmem_cache_free(se_ua_cache, ua);
249 }
250 spin_unlock(&deve->ua_lock);
251 rcu_read_unlock();
252
253 pr_debug("[%s]: %s UNIT ATTENTION condition with"
254 " INTLCK_CTRL: %d, mapped LUN: %llu, got CDB: 0x%02x"
255 " reported ASC: 0x%02x, ASCQ: 0x%02x\n",
256 nacl->se_tpg->se_tpg_tfo->fabric_name,
257 (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
258 "Releasing", dev->dev_attrib.emulate_ua_intlck_ctrl,
259 cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);
260
261 return head == 0;
262 }
263
264 int core_scsi3_ua_clear_for_request_sense(
265 struct se_cmd *cmd,
266 u8 *asc,
267 u8 *ascq)
268 {
269 struct se_dev_entry *deve;
270 struct se_session *sess = cmd->se_sess;
271 struct se_node_acl *nacl;
272 struct se_ua *ua = NULL, *ua_p;
273 int head = 1;
274
275 if (!sess)
276 return -EINVAL;
277
278 nacl = sess->se_node_acl;
279 if (!nacl)
280 return -EINVAL;
281
282 rcu_read_lock();
283 deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
284 if (!deve) {
285 rcu_read_unlock();
286 return -EINVAL;
287 }
288 if (list_empty_careful(&deve->ua_list)) {
289 rcu_read_unlock();
290 return -EPERM;
291 }
292 /*
293 * The highest priority Unit Attentions are placed at the head of the
294 * struct se_dev_entry->ua_list. The First (and hence highest priority)
295 * ASC/ASCQ will be returned in REQUEST_SENSE payload data for the
296 * matching struct se_lun.
297 *
298 * Once the returning ASC/ASCQ values are set, we go ahead and
299 * release all of the Unit Attention conditions for the associated
300 * struct se_lun.
301 */
302 spin_lock(&deve->ua_lock);
303 list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
304 if (head) {
305 *asc = ua->ua_asc;
306 *ascq = ua->ua_ascq;
307 head = 0;
308 }
309 list_del(&ua->ua_nacl_list);
310 kmem_cache_free(se_ua_cache, ua);
311 }
312 spin_unlock(&deve->ua_lock);
313 rcu_read_unlock();
314
315 pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
316 " LUN: %llu, got REQUEST_SENSE reported ASC: 0x%02x,"
317 " ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->fabric_name,
318 cmd->orig_fe_lun, *asc, *ascq);
319
320 return (head) ? -EPERM : 0;
321 }