linux/drivers/target/target_core_ua.c
David Disseldorp 1bf630fddd scsi: target: use an enum to track emulate_ua_intlck_ctrl
The emulate_ua_intlck_ctrl device attribute accepts values of 0, 1 or 2 via
ConfigFS, which map to unit attention interlocks control codes in the MODE
SENSE control Mode Page.  Use an enum to track these values so that it's
clear that, unlike the remaining emulate_X attributes,
emulate_ua_intlck_ctrl isn't boolean.

Link: https://marc.info/?l=target-devel&m=158227825428798
Suggested-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2020-02-21 17:37:16 -05:00

324 lines
8.3 KiB
C

// 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;
bool dev_ua_intlck_clear = (dev->dev_attrib.emulate_ua_intlck_ctrl
== TARGET_UA_INTLCK_CTRL_CLEAR);
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_ua_intlck_clear) {
*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_ua_intlck_clear ? "Releasing" : "Reporting",
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;
}