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linux/drivers/target/target_core_ua.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*******************************************************************************
* Filename: target_core_ua.c
*
* This file contains logic for SPC-3 Unit Attention emulation
*
* (c) Copyright 2009-2013 Datera, Inc.
*
* Nicholas A. Bellinger <nab@kernel.org>
*
******************************************************************************/
#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;
}
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