[linux.git] / drivers / target / target_core_ua.c

/*******************************************************************************
 * Filename: target_core_ua.c
 *
 * This file contains logic for SPC-3 Unit Attention emulation
 *
 * (c) Copyright 2009-2013 Datera, Inc.
 *
 * Nicholas A. Bellinger <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 ******************************************************************************/

#include <linux/slab.h>
#include <linux/spinlock.h>
#include <scsi/scsi_proto.h>

#include <target/target_core_base.h>
#include <target/target_core_fabric.h>

#include "target_core_internal.h"
#include "target_core_alua.h"
#include "target_core_pr.h"
#include "target_core_ua.h"

sense_reason_t
target_scsi3_ua_check(struct se_cmd *cmd)
{
	struct se_dev_entry *deve;
	struct se_session *sess = cmd->se_sess;
	struct se_node_acl *nacl;

	if (!sess)
		return 0;

	nacl = sess->se_node_acl;
	if (!nacl)
		return 0;

	rcu_read_lock();
	deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
	if (!deve) {
		rcu_read_unlock();
		return 0;
	}
	if (list_empty_careful(&deve->ua_list)) {
		rcu_read_unlock();
		return 0;
	}
	rcu_read_unlock();
	/*
	 * From sam4r14, section 5.14 Unit attention condition:
	 *
	 * a) if an INQUIRY command enters the enabled command state, the
	 *    device server shall process the INQUIRY command and shall neither
	 *    report nor clear any unit attention condition;
	 * b) if a REPORT LUNS command enters the enabled command state, the
	 *    device server shall process the REPORT LUNS command and shall not
	 *    report any unit attention condition;
	 * e) if a REQUEST SENSE command enters the enabled command state while
	 *    a unit attention condition exists for the SCSI initiator port
	 *    associated with the I_T nexus on which the REQUEST SENSE command
	 *    was received, then the device server shall process the command
	 *    and either:
	 */
	switch (cmd->t_task_cdb[0]) {
	case INQUIRY:
	case REPORT_LUNS:
	case REQUEST_SENSE:
		return 0;
	default:
		return TCM_CHECK_CONDITION_UNIT_ATTENTION;
	}
}

int core_scsi3_ua_allocate(
	struct se_dev_entry *deve,
	u8 asc,
	u8 ascq)
{
	struct se_ua *ua, *ua_p, *ua_tmp;

	ua = kmem_cache_zalloc(se_ua_cache, GFP_ATOMIC);
	if (!ua) {
		pr_err("Unable to allocate struct se_ua\n");
		return -ENOMEM;
	}
	INIT_LIST_HEAD(&ua->ua_nacl_list);

	ua->ua_asc = asc;
	ua->ua_ascq = ascq;

	spin_lock(&deve->ua_lock);
	list_for_each_entry_safe(ua_p, ua_tmp, &deve->ua_list, ua_nacl_list) {
		/*
		 * Do not report the same UNIT ATTENTION twice..
		 */
		if ((ua_p->ua_asc == asc) && (ua_p->ua_ascq == ascq)) {
			spin_unlock(&deve->ua_lock);
			kmem_cache_free(se_ua_cache, ua);
			return 0;
		}
		/*
		 * Attach the highest priority Unit Attention to
		 * the head of the list following sam4r14,
		 * Section 5.14 Unit Attention Condition:
		 *
		 * POWER ON, RESET, OR BUS DEVICE RESET OCCURRED highest
		 * POWER ON OCCURRED or
		 * DEVICE INTERNAL RESET
		 * SCSI BUS RESET OCCURRED or
		 * MICROCODE HAS BEEN CHANGED or
		 * protocol specific
		 * BUS DEVICE RESET FUNCTION OCCURRED
		 * I_T NEXUS LOSS OCCURRED
		 * COMMANDS CLEARED BY POWER LOSS NOTIFICATION
		 * all others                                    Lowest
		 *
		 * Each of the ASCQ codes listed above are defined in
		 * the 29h ASC family, see spc4r17 Table D.1
		 */
		if (ua_p->ua_asc == 0x29) {
			if ((asc == 0x29) && (ascq > ua_p->ua_ascq))
				list_add(&ua->ua_nacl_list,
						&deve->ua_list);
			else
				list_add_tail(&ua->ua_nacl_list,
						&deve->ua_list);
		} else if (ua_p->ua_asc == 0x2a) {
			/*
			 * Incoming Family 29h ASCQ codes will override
			 * Family 2AHh ASCQ codes for Unit Attention condition.
			 */
			if ((asc == 0x29) || (ascq > ua_p->ua_asc))
				list_add(&ua->ua_nacl_list,
					&deve->ua_list);
			else
				list_add_tail(&ua->ua_nacl_list,
						&deve->ua_list);
		} else
			list_add_tail(&ua->ua_nacl_list,
				&deve->ua_list);
		spin_unlock(&deve->ua_lock);

		return 0;
	}
	list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
	spin_unlock(&deve->ua_lock);

	pr_debug("Allocated UNIT ATTENTION, mapped LUN: %llu, ASC:"
		" 0x%02x, ASCQ: 0x%02x\n", deve->mapped_lun,
		asc, ascq);

	return 0;
}

void target_ua_allocate_lun(struct se_node_acl *nacl,
			    u32 unpacked_lun, u8 asc, u8 ascq)
{
	struct se_dev_entry *deve;

	if (!nacl)
		return;

	rcu_read_lock();
	deve = target_nacl_find_deve(nacl, unpacked_lun);
	if (!deve) {
		rcu_read_unlock();
		return;
	}

	core_scsi3_ua_allocate(deve, asc, ascq);
	rcu_read_unlock();
}

void core_scsi3_ua_release_all(
	struct se_dev_entry *deve)
{
	struct se_ua *ua, *ua_p;

	spin_lock(&deve->ua_lock);
	list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
		list_del(&ua->ua_nacl_list);
		kmem_cache_free(se_ua_cache, ua);
	}
	spin_unlock(&deve->ua_lock);
}

/*
 * Dequeue a unit attention from the unit attention list. This function
 * returns true if the dequeuing succeeded and if *@key, *@asc and *@ascq have
 * been set.
 */
bool core_scsi3_ua_for_check_condition(struct se_cmd *cmd, u8 *key, u8 *asc,
				       u8 *ascq)
{
	struct se_device *dev = cmd->se_dev;
	struct se_dev_entry *deve;
	struct se_session *sess = cmd->se_sess;
	struct se_node_acl *nacl;
	struct se_ua *ua = NULL, *ua_p;
	int head = 1;

	if (WARN_ON_ONCE(!sess))
		return false;

	nacl = sess->se_node_acl;
	if (WARN_ON_ONCE(!nacl))
		return false;

	rcu_read_lock();
	deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
	if (!deve) {
		rcu_read_unlock();
		*key = ILLEGAL_REQUEST;
		*asc = 0x25; /* LOGICAL UNIT NOT SUPPORTED */
		*ascq = 0;
		return true;
	}
	*key = UNIT_ATTENTION;
	/*
	 * The highest priority Unit Attentions are placed at the head of the
	 * struct se_dev_entry->ua_list, and will be returned in CHECK_CONDITION +
	 * sense data for the received CDB.
	 */
	spin_lock(&deve->ua_lock);
	list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
		/*
		 * For ua_intlck_ctrl code not equal to 00b, only report the
		 * highest priority UNIT_ATTENTION and ASC/ASCQ without
		 * clearing it.
		 */
		if (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) {
			*asc = ua->ua_asc;
			*ascq = ua->ua_ascq;
			break;
		}
		/*
		 * Otherwise for the default 00b, release the UNIT ATTENTION
		 * condition.  Return the ASC/ASCQ of the highest priority UA
		 * (head of the list) in the outgoing CHECK_CONDITION + sense.
		 */
		if (head) {
			*asc = ua->ua_asc;
			*ascq = ua->ua_ascq;
			head = 0;
		}
		list_del(&ua->ua_nacl_list);
		kmem_cache_free(se_ua_cache, ua);
	}
	spin_unlock(&deve->ua_lock);
	rcu_read_unlock();

	pr_debug("[%s]: %s UNIT ATTENTION condition with"
		" INTLCK_CTRL: %d, mapped LUN: %llu, got CDB: 0x%02x"
		" reported ASC: 0x%02x, ASCQ: 0x%02x\n",
		nacl->se_tpg->se_tpg_tfo->fabric_name,
		(dev->dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
		"Releasing", dev->dev_attrib.emulate_ua_intlck_ctrl,
		cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);

	return head == 0;
}

int core_scsi3_ua_clear_for_request_sense(
	struct se_cmd *cmd,
	u8 *asc,
	u8 *ascq)
{
	struct se_dev_entry *deve;
	struct se_session *sess = cmd->se_sess;
	struct se_node_acl *nacl;
	struct se_ua *ua = NULL, *ua_p;
	int head = 1;

	if (!sess)
		return -EINVAL;

	nacl = sess->se_node_acl;
	if (!nacl)
		return -EINVAL;

	rcu_read_lock();
	deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
	if (!deve) {
		rcu_read_unlock();
		return -EINVAL;
	}
	if (list_empty_careful(&deve->ua_list)) {
		rcu_read_unlock();
		return -EPERM;
	}
	/*
	 * The highest priority Unit Attentions are placed at the head of the
	 * struct se_dev_entry->ua_list.  The First (and hence highest priority)
	 * ASC/ASCQ will be returned in REQUEST_SENSE payload data for the
	 * matching struct se_lun.
	 *
	 * Once the returning ASC/ASCQ values are set, we go ahead and
	 * release all of the Unit Attention conditions for the associated
	 * struct se_lun.
	 */
	spin_lock(&deve->ua_lock);
	list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
		if (head) {
			*asc = ua->ua_asc;
			*ascq = ua->ua_ascq;
			head = 0;
		}
		list_del(&ua->ua_nacl_list);
		kmem_cache_free(se_ua_cache, ua);
	}
	spin_unlock(&deve->ua_lock);
	rcu_read_unlock();

	pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
		" LUN: %llu, got REQUEST_SENSE reported ASC: 0x%02x,"
		" ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->fabric_name,
		cmd->orig_fe_lun, *asc, *ascq);

	return (head) ? -EPERM : 0;
}
Commit	Line	Data
c66ac9db NB	1	/*******************************************************************************
	2	* Filename: target_core_ua.c
	3	*
	4	* This file contains logic for SPC-3 Unit Attention emulation
	5	*
4c76251e	6	* (c) Copyright 2009-2013 Datera, Inc.
c66ac9db NB	7	*
	8	* Nicholas A. Bellinger <[email protected]>
	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
c66ac9db NB	26	#include <linux/slab.h>
c66ac9db NB	27	#include <linux/spinlock.h>
ba929992	28	#include <scsi/scsi_proto.h>
c66ac9db NB	29
c66ac9db NB	30	#include <target/target_core_base.h>
c4795fb2	31	#include <target/target_core_fabric.h>
c66ac9db	32
e26d99ae	33	#include "target_core_internal.h"
c66ac9db	34	#include "target_core_alua.h"
c66ac9db NB	35	#include "target_core_pr.h"
	36	#include "target_core_ua.h"
	37
de103c93 CH	38	sense_reason_t
de103c93 CH	39	target_scsi3_ua_check(struct se_cmd *cmd)
c66ac9db NB	40	{
	41	struct se_dev_entry *deve;
	42	struct se_session *sess = cmd->se_sess;
	43	struct se_node_acl *nacl;
	44
6708bb27	45	if (!sess)
c66ac9db NB	46	return 0;
	47
	48	nacl = sess->se_node_acl;
6708bb27	49	if (!nacl)
c66ac9db NB	50	return 0;
c66ac9db NB	51
29a05dee NB	52	rcu_read_lock();
	53	deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
	54	if (!deve) {
	55	rcu_read_unlock();
c66ac9db	56	return 0;
29a05dee	57	}
e936a38a	58	if (list_empty_careful(&deve->ua_list)) {
29a05dee NB	59	rcu_read_unlock();
	60	return 0;
	61	}
	62	rcu_read_unlock();
c66ac9db NB	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	*/
de103c93	78	switch (cmd->t_task_cdb[0]) {
c66ac9db NB	79	case INQUIRY:
	80	case REPORT_LUNS:
	81	case REQUEST_SENSE:
	82	return 0;
	83	default:
de103c93	84	return TCM_CHECK_CONDITION_UNIT_ATTENTION;
c66ac9db	85	}
c66ac9db NB	86	}
	87
	88	int core_scsi3_ua_allocate(
c51c8e7b	89	struct se_dev_entry *deve,
c66ac9db NB	90	u8 asc,
	91	u8 ascq)
	92	{
c66ac9db	93	struct se_ua ua, ua_p, *ua_tmp;
c66ac9db NB	94
c66ac9db NB	95	ua = kmem_cache_zalloc(se_ua_cache, GFP_ATOMIC);
6708bb27 AG	96	if (!ua) {
6708bb27 AG	97	pr_err("Unable to allocate struct se_ua\n");
e3d6f909	98	return -ENOMEM;
c66ac9db	99	}
c66ac9db NB	100	INIT_LIST_HEAD(&ua->ua_nacl_list);
c66ac9db NB	101
c66ac9db NB	102	ua->ua_asc = asc;
	103	ua->ua_ascq = ascq;
	104
c66ac9db NB	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);
c66ac9db NB	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);
c66ac9db	156
c66ac9db NB	157	return 0;
	158	}
	159	list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
	160	spin_unlock(&deve->ua_lock);
c66ac9db	161
c51c8e7b HR	162	pr_debug("Allocated UNIT ATTENTION, mapped LUN: %llu, ASC:"
c51c8e7b HR	163	" 0x%02x, ASCQ: 0x%02x\n", deve->mapped_lun,
c66ac9db NB	164	asc, ascq);
c66ac9db NB	165
c66ac9db NB	166	return 0;
	167	}
	168
c51c8e7b HR	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
c66ac9db NB	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);
c66ac9db NB	197	}
	198	spin_unlock(&deve->ua_lock);
	199	}
	200
325c1e8b BVA	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)
c66ac9db	208	{
5951146d	209	struct se_device *dev = cmd->se_dev;
c66ac9db NB	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
325c1e8b BVA	216	if (WARN_ON_ONCE(!sess))
325c1e8b BVA	217	return false;
c66ac9db NB	218
c66ac9db NB	219	nacl = sess->se_node_acl;
325c1e8b BVA	220	if (WARN_ON_ONCE(!nacl))
325c1e8b BVA	221	return false;
c66ac9db	222
29a05dee NB	223	rcu_read_lock();
	224	deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
	225	if (!deve) {
	226	rcu_read_unlock();
325c1e8b BVA	227	*key = ILLEGAL_REQUEST;
	228	asc = 0x25; / LOGICAL UNIT NOT SUPPORTED */
	229	*ascq = 0;
	230	return true;
c66ac9db	231	}
325c1e8b	232	*key = UNIT_ATTENTION;
c66ac9db NB	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	*/
0fd97ccf	245	if (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) {
c66ac9db NB	246	*asc = ua->ua_asc;
	247	*ascq = ua->ua_ascq;
	248	break;
	249	}
	250	/*
	251	* Otherwise for the default 00b, release the UNIT ATTENTION
25985edc	252	* condition. Return the ASC/ASCQ of the highest priority UA
c66ac9db NB	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);
c66ac9db NB	262	}
c66ac9db NB	263	spin_unlock(&deve->ua_lock);
29a05dee	264	rcu_read_unlock();
c66ac9db	265
6708bb27	266	pr_debug("[%s]: %s UNIT ATTENTION condition with"
f2d30680	267	" INTLCK_CTRL: %d, mapped LUN: %llu, got CDB: 0x%02x"
c66ac9db	268	" reported ASC: 0x%02x, ASCQ: 0x%02x\n",
30c7ca93	269	nacl->se_tpg->se_tpg_tfo->fabric_name,
0fd97ccf CH	270	(dev->dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
0fd97ccf CH	271	"Releasing", dev->dev_attrib.emulate_ua_intlck_ctrl,
a1d8b49a	272	cmd->orig_fe_lun, cmd->t_task_cdb[0], asc, ascq);
325c1e8b BVA	273
325c1e8b BVA	274	return head == 0;
c66ac9db NB	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
6708bb27	288	if (!sess)
e3d6f909	289	return -EINVAL;
c66ac9db NB	290
c66ac9db NB	291	nacl = sess->se_node_acl;
6708bb27	292	if (!nacl)
e3d6f909	293	return -EINVAL;
c66ac9db	294
29a05dee NB	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	}
e936a38a	301	if (list_empty_careful(&deve->ua_list)) {
29a05dee	302	rcu_read_unlock();
e3d6f909	303	return -EPERM;
c66ac9db NB	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
25985edc	312	* release all of the Unit Attention conditions for the associated
c66ac9db NB	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);
c66ac9db NB	324	}
c66ac9db NB	325	spin_unlock(&deve->ua_lock);
29a05dee	326	rcu_read_unlock();
c66ac9db	327
6708bb27	328	pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
f2d30680	329	" LUN: %llu, got REQUEST_SENSE reported ASC: 0x%02x,"
30c7ca93	330	" ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->fabric_name,
c66ac9db NB	331	cmd->orig_fe_lun, asc, ascq);
c66ac9db NB	332
e3d6f909	333	return (head) ? -EPERM : 0;
c66ac9db	334	}