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 
38 sense_reason_t
39 target_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 (list_empty_careful(&deve->ua_list)) {
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 
88 int 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 		return 0;
158 	}
159 	list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
160 	spin_unlock(&deve->ua_lock);
161 
162 	pr_debug("Allocated UNIT ATTENTION, mapped LUN: %llu, ASC:"
163 		" 0x%02x, ASCQ: 0x%02x\n", deve->mapped_lun,
164 		asc, ascq);
165 
166 	return 0;
167 }
168 
169 void target_ua_allocate_lun(struct se_node_acl *nacl,
170 			    u32 unpacked_lun, u8 asc, u8 ascq)
171 {
172 	struct se_dev_entry *deve;
173 
174 	if (!nacl)
175 		return;
176 
177 	rcu_read_lock();
178 	deve = target_nacl_find_deve(nacl, unpacked_lun);
179 	if (!deve) {
180 		rcu_read_unlock();
181 		return;
182 	}
183 
184 	core_scsi3_ua_allocate(deve, asc, ascq);
185 	rcu_read_unlock();
186 }
187 
188 void core_scsi3_ua_release_all(
189 	struct se_dev_entry *deve)
190 {
191 	struct se_ua *ua, *ua_p;
192 
193 	spin_lock(&deve->ua_lock);
194 	list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
195 		list_del(&ua->ua_nacl_list);
196 		kmem_cache_free(se_ua_cache, ua);
197 	}
198 	spin_unlock(&deve->ua_lock);
199 }
200 
201 /*
202  * Dequeue a unit attention from the unit attention list. This function
203  * returns true if the dequeuing succeeded and if *@key, *@asc and *@ascq have
204  * been set.
205  */
206 bool core_scsi3_ua_for_check_condition(struct se_cmd *cmd, u8 *key, u8 *asc,
207 				       u8 *ascq)
208 {
209 	struct se_device *dev = cmd->se_dev;
210 	struct se_dev_entry *deve;
211 	struct se_session *sess = cmd->se_sess;
212 	struct se_node_acl *nacl;
213 	struct se_ua *ua = NULL, *ua_p;
214 	int head = 1;
215 
216 	if (WARN_ON_ONCE(!sess))
217 		return false;
218 
219 	nacl = sess->se_node_acl;
220 	if (WARN_ON_ONCE(!nacl))
221 		return false;
222 
223 	rcu_read_lock();
224 	deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
225 	if (!deve) {
226 		rcu_read_unlock();
227 		*key = ILLEGAL_REQUEST;
228 		*asc = 0x25; /* LOGICAL UNIT NOT SUPPORTED */
229 		*ascq = 0;
230 		return true;
231 	}
232 	*key = UNIT_ATTENTION;
233 	/*
234 	 * The highest priority Unit Attentions are placed at the head of the
235 	 * struct se_dev_entry->ua_list, and will be returned in CHECK_CONDITION +
236 	 * sense data for the received CDB.
237 	 */
238 	spin_lock(&deve->ua_lock);
239 	list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
240 		/*
241 		 * For ua_intlck_ctrl code not equal to 00b, only report the
242 		 * highest priority UNIT_ATTENTION and ASC/ASCQ without
243 		 * clearing it.
244 		 */
245 		if (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) {
246 			*asc = ua->ua_asc;
247 			*ascq = ua->ua_ascq;
248 			break;
249 		}
250 		/*
251 		 * Otherwise for the default 00b, release the UNIT ATTENTION
252 		 * condition.  Return the ASC/ASCQ of the highest priority UA
253 		 * (head of the list) in the outgoing CHECK_CONDITION + sense.
254 		 */
255 		if (head) {
256 			*asc = ua->ua_asc;
257 			*ascq = ua->ua_ascq;
258 			head = 0;
259 		}
260 		list_del(&ua->ua_nacl_list);
261 		kmem_cache_free(se_ua_cache, ua);
262 	}
263 	spin_unlock(&deve->ua_lock);
264 	rcu_read_unlock();
265 
266 	pr_debug("[%s]: %s UNIT ATTENTION condition with"
267 		" INTLCK_CTRL: %d, mapped LUN: %llu, got CDB: 0x%02x"
268 		" reported ASC: 0x%02x, ASCQ: 0x%02x\n",
269 		nacl->se_tpg->se_tpg_tfo->fabric_name,
270 		(dev->dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
271 		"Releasing", dev->dev_attrib.emulate_ua_intlck_ctrl,
272 		cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);
273 
274 	return head == 0;
275 }
276 
277 int core_scsi3_ua_clear_for_request_sense(
278 	struct se_cmd *cmd,
279 	u8 *asc,
280 	u8 *ascq)
281 {
282 	struct se_dev_entry *deve;
283 	struct se_session *sess = cmd->se_sess;
284 	struct se_node_acl *nacl;
285 	struct se_ua *ua = NULL, *ua_p;
286 	int head = 1;
287 
288 	if (!sess)
289 		return -EINVAL;
290 
291 	nacl = sess->se_node_acl;
292 	if (!nacl)
293 		return -EINVAL;
294 
295 	rcu_read_lock();
296 	deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
297 	if (!deve) {
298 		rcu_read_unlock();
299 		return -EINVAL;
300 	}
301 	if (list_empty_careful(&deve->ua_list)) {
302 		rcu_read_unlock();
303 		return -EPERM;
304 	}
305 	/*
306 	 * The highest priority Unit Attentions are placed at the head of the
307 	 * struct se_dev_entry->ua_list.  The First (and hence highest priority)
308 	 * ASC/ASCQ will be returned in REQUEST_SENSE payload data for the
309 	 * matching struct se_lun.
310 	 *
311 	 * Once the returning ASC/ASCQ values are set, we go ahead and
312 	 * release all of the Unit Attention conditions for the associated
313 	 * struct se_lun.
314 	 */
315 	spin_lock(&deve->ua_lock);
316 	list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
317 		if (head) {
318 			*asc = ua->ua_asc;
319 			*ascq = ua->ua_ascq;
320 			head = 0;
321 		}
322 		list_del(&ua->ua_nacl_list);
323 		kmem_cache_free(se_ua_cache, ua);
324 	}
325 	spin_unlock(&deve->ua_lock);
326 	rcu_read_unlock();
327 
328 	pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
329 		" LUN: %llu, got REQUEST_SENSE reported ASC: 0x%02x,"
330 		" ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->fabric_name,
331 		cmd->orig_fe_lun, *asc, *ascq);
332 
333 	return (head) ? -EPERM : 0;
334 }
335