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