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 	bool dev_ua_intlck_clear = (dev->dev_attrib.emulate_ua_intlck_ctrl
203 						== TARGET_UA_INTLCK_CTRL_CLEAR);
204 
205 	if (WARN_ON_ONCE(!sess))
206 		return false;
207 
208 	nacl = sess->se_node_acl;
209 	if (WARN_ON_ONCE(!nacl))
210 		return false;
211 
212 	rcu_read_lock();
213 	deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
214 	if (!deve) {
215 		rcu_read_unlock();
216 		*key = ILLEGAL_REQUEST;
217 		*asc = 0x25; /* LOGICAL UNIT NOT SUPPORTED */
218 		*ascq = 0;
219 		return true;
220 	}
221 	*key = UNIT_ATTENTION;
222 	/*
223 	 * The highest priority Unit Attentions are placed at the head of the
224 	 * struct se_dev_entry->ua_list, and will be returned in CHECK_CONDITION +
225 	 * sense data for the received CDB.
226 	 */
227 	spin_lock(&deve->ua_lock);
228 	list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
229 		/*
230 		 * For ua_intlck_ctrl code not equal to 00b, only report the
231 		 * highest priority UNIT_ATTENTION and ASC/ASCQ without
232 		 * clearing it.
233 		 */
234 		if (!dev_ua_intlck_clear) {
235 			*asc = ua->ua_asc;
236 			*ascq = ua->ua_ascq;
237 			break;
238 		}
239 		/*
240 		 * Otherwise for the default 00b, release the UNIT ATTENTION
241 		 * condition.  Return the ASC/ASCQ of the highest priority UA
242 		 * (head of the list) in the outgoing CHECK_CONDITION + sense.
243 		 */
244 		if (head) {
245 			*asc = ua->ua_asc;
246 			*ascq = ua->ua_ascq;
247 			head = 0;
248 		}
249 		list_del(&ua->ua_nacl_list);
250 		kmem_cache_free(se_ua_cache, ua);
251 	}
252 	spin_unlock(&deve->ua_lock);
253 	rcu_read_unlock();
254 
255 	pr_debug("[%s]: %s UNIT ATTENTION condition with"
256 		" INTLCK_CTRL: %d, mapped LUN: %llu, got CDB: 0x%02x"
257 		" reported ASC: 0x%02x, ASCQ: 0x%02x\n",
258 		nacl->se_tpg->se_tpg_tfo->fabric_name,
259 		dev_ua_intlck_clear ? "Releasing" : "Reporting",
260 		dev->dev_attrib.emulate_ua_intlck_ctrl,
261 		cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);
262 
263 	return head == 0;
264 }
265 
266 int core_scsi3_ua_clear_for_request_sense(
267 	struct se_cmd *cmd,
268 	u8 *asc,
269 	u8 *ascq)
270 {
271 	struct se_dev_entry *deve;
272 	struct se_session *sess = cmd->se_sess;
273 	struct se_node_acl *nacl;
274 	struct se_ua *ua = NULL, *ua_p;
275 	int head = 1;
276 
277 	if (!sess)
278 		return -EINVAL;
279 
280 	nacl = sess->se_node_acl;
281 	if (!nacl)
282 		return -EINVAL;
283 
284 	rcu_read_lock();
285 	deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
286 	if (!deve) {
287 		rcu_read_unlock();
288 		return -EINVAL;
289 	}
290 	if (list_empty_careful(&deve->ua_list)) {
291 		rcu_read_unlock();
292 		return -EPERM;
293 	}
294 	/*
295 	 * The highest priority Unit Attentions are placed at the head of the
296 	 * struct se_dev_entry->ua_list.  The First (and hence highest priority)
297 	 * ASC/ASCQ will be returned in REQUEST_SENSE payload data for the
298 	 * matching struct se_lun.
299 	 *
300 	 * Once the returning ASC/ASCQ values are set, we go ahead and
301 	 * release all of the Unit Attention conditions for the associated
302 	 * struct se_lun.
303 	 */
304 	spin_lock(&deve->ua_lock);
305 	list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
306 		if (head) {
307 			*asc = ua->ua_asc;
308 			*ascq = ua->ua_ascq;
309 			head = 0;
310 		}
311 		list_del(&ua->ua_nacl_list);
312 		kmem_cache_free(se_ua_cache, ua);
313 	}
314 	spin_unlock(&deve->ua_lock);
315 	rcu_read_unlock();
316 
317 	pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
318 		" LUN: %llu, got REQUEST_SENSE reported ASC: 0x%02x,"
319 		" ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->fabric_name,
320 		cmd->orig_fe_lun, *asc, *ascq);
321 
322 	return (head) ? -EPERM : 0;
323 }
324