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kernel/drivers/target/target_core_tmr.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*******************************************************************************
* Filename: target_core_tmr.c
*
* This file contains SPC-3 task management infrastructure
*
* (c) Copyright 2009-2013 Datera, Inc.
*
* Nicholas A. Bellinger <nab@kernel.org>
*
******************************************************************************/
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/export.h>
#include <target/target_core_base.h>
#include <target/target_core_backend.h>
#include <target/target_core_fabric.h>
#include "target_core_internal.h"
#include "target_core_alua.h"
#include "target_core_pr.h"
int core_tmr_alloc_req(
struct se_cmd *se_cmd,
void *fabric_tmr_ptr,
u8 function,
gfp_t gfp_flags)
{
struct se_tmr_req *tmr;
tmr = kzalloc(sizeof(struct se_tmr_req), gfp_flags);
if (!tmr) {
pr_err("Unable to allocate struct se_tmr_req\n");
return -ENOMEM;
}
se_cmd->se_cmd_flags |= SCF_SCSI_TMR_CDB;
se_cmd->se_tmr_req = tmr;
tmr->task_cmd = se_cmd;
tmr->fabric_tmr_ptr = fabric_tmr_ptr;
tmr->function = function;
INIT_LIST_HEAD(&tmr->tmr_list);
return 0;
}
EXPORT_SYMBOL(core_tmr_alloc_req);
void core_tmr_release_req(struct se_tmr_req *tmr)
{
kfree(tmr);
}
static int target_check_cdb_and_preempt(struct list_head *list,
struct se_cmd *cmd)
{
struct t10_pr_registration *reg;
if (!list)
return 0;
list_for_each_entry(reg, list, pr_reg_abort_list) {
if (reg->pr_res_key == cmd->pr_res_key)
return 0;
}
return 1;
}
static bool __target_check_io_state(struct se_cmd *se_cmd,
struct se_session *tmr_sess, bool tas)
{
struct se_session *sess = se_cmd->se_sess;
lockdep_assert_held(&sess->sess_cmd_lock);
/*
* If command already reached CMD_T_COMPLETE state within
* target_complete_cmd() or CMD_T_FABRIC_STOP due to shutdown,
* this se_cmd has been passed to fabric driver and will
* not be aborted.
*
* Otherwise, obtain a local se_cmd->cmd_kref now for TMR
* ABORT_TASK + LUN_RESET for CMD_T_ABORTED processing as
* long as se_cmd->cmd_kref is still active unless zero.
*/
spin_lock(&se_cmd->t_state_lock);
if (se_cmd->transport_state & (CMD_T_COMPLETE | CMD_T_FABRIC_STOP)) {
pr_debug("Attempted to abort io tag: %llu already complete or"
" fabric stop, skipping\n", se_cmd->tag);
spin_unlock(&se_cmd->t_state_lock);
return false;
}
se_cmd->transport_state |= CMD_T_ABORTED;
if ((tmr_sess != se_cmd->se_sess) && tas)
se_cmd->transport_state |= CMD_T_TAS;
spin_unlock(&se_cmd->t_state_lock);
return kref_get_unless_zero(&se_cmd->cmd_kref);
}
void core_tmr_abort_task(
struct se_device *dev,
struct se_tmr_req *tmr,
struct se_session *se_sess)
{
LIST_HEAD(aborted_list);
struct se_cmd *se_cmd, *next;
unsigned long flags;
bool rc;
u64 ref_tag;
int i;
for (i = 0; i < dev->queue_cnt; i++) {
flush_work(&dev->queues[i].sq.work);
spin_lock_irqsave(&dev->queues[i].lock, flags);
list_for_each_entry_safe(se_cmd, next, &dev->queues[i].state_list,
state_list) {
if (se_sess != se_cmd->se_sess)
continue;
/*
* skip task management functions, including
* tmr->task_cmd
*/
if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
continue;
ref_tag = se_cmd->tag;
if (tmr->ref_task_tag != ref_tag)
continue;
pr_err("ABORT_TASK: Found referenced %s task_tag: %llu\n",
se_cmd->se_tfo->fabric_name, ref_tag);
spin_lock(&se_sess->sess_cmd_lock);
rc = __target_check_io_state(se_cmd, se_sess, 0);
spin_unlock(&se_sess->sess_cmd_lock);
if (!rc)
continue;
list_move_tail(&se_cmd->state_list, &aborted_list);
se_cmd->state_active = false;
spin_unlock_irqrestore(&dev->queues[i].lock, flags);
if (dev->transport->tmr_notify)
dev->transport->tmr_notify(dev, TMR_ABORT_TASK,
&aborted_list);
list_del_init(&se_cmd->state_list);
target_put_cmd_and_wait(se_cmd);
pr_err("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for ref_tag: %llu\n",
ref_tag);
tmr->response = TMR_FUNCTION_COMPLETE;
atomic_long_inc(&dev->aborts_complete);
return;
}
spin_unlock_irqrestore(&dev->queues[i].lock, flags);
}
if (dev->transport->tmr_notify)
dev->transport->tmr_notify(dev, TMR_ABORT_TASK, &aborted_list);
printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
tmr->ref_task_tag);
tmr->response = TMR_TASK_DOES_NOT_EXIST;
atomic_long_inc(&dev->aborts_no_task);
}
static void core_tmr_drain_tmr_list(
struct se_device *dev,
struct se_tmr_req *tmr,
struct list_head *preempt_and_abort_list)
{
LIST_HEAD(drain_tmr_list);
struct se_session *sess;
struct se_tmr_req *tmr_p, *tmr_pp;
struct se_cmd *cmd;
unsigned long flags;
bool rc;
/*
* Release all pending and outgoing TMRs aside from the received
* LUN_RESET tmr..
*/
spin_lock_irqsave(&dev->se_tmr_lock, flags);
list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
if (tmr_p == tmr)
continue;
cmd = tmr_p->task_cmd;
if (!cmd) {
pr_err("Unable to locate struct se_cmd for TMR\n");
continue;
}
/*
* We only execute one LUN_RESET at a time so we can't wait
* on them below.
*/
if (tmr_p->function == TMR_LUN_RESET)
continue;
/*
* If this function was called with a valid pr_res_key
* parameter (eg: for PROUT PREEMPT_AND_ABORT service action
* skip non registration key matching TMRs.
*/
if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
continue;
sess = cmd->se_sess;
if (WARN_ON_ONCE(!sess))
continue;
spin_lock(&sess->sess_cmd_lock);
rc = __target_check_io_state(cmd, sess, 0);
spin_unlock(&sess->sess_cmd_lock);
if (!rc) {
printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
continue;
}
list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
tmr_p->tmr_dev = NULL;
}
spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
list_del_init(&tmr_p->tmr_list);
cmd = tmr_p->task_cmd;
pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
" Response: 0x%02x, t_state: %d\n",
(preempt_and_abort_list) ? "Preempt" : "", tmr_p,
tmr_p->function, tmr_p->response, cmd->t_state);
target_put_cmd_and_wait(cmd);
}
}
/**
* core_tmr_drain_state_list() - abort SCSI commands associated with a device
*
* @dev: Device for which to abort outstanding SCSI commands.
* @prout_cmd: Pointer to the SCSI PREEMPT AND ABORT if this function is called
* to realize the PREEMPT AND ABORT functionality.
* @tmr_sess: Session through which the LUN RESET has been received.
* @tas: Task Aborted Status (TAS) bit from the SCSI control mode page.
* A quote from SPC-4, paragraph "7.5.10 Control mode page":
* "A task aborted status (TAS) bit set to zero specifies that
* aborted commands shall be terminated by the device server
* without any response to the application client. A TAS bit set
* to one specifies that commands aborted by the actions of an I_T
* nexus other than the I_T nexus on which the command was
* received shall be completed with TASK ABORTED status."
* @preempt_and_abort_list: For the PREEMPT AND ABORT functionality, a list
* with registrations that will be preempted.
*/
static void core_tmr_drain_state_list(
struct se_device *dev,
struct se_cmd *prout_cmd,
struct se_session *tmr_sess,
bool tas,
struct list_head *preempt_and_abort_list)
{
LIST_HEAD(drain_task_list);
struct se_session *sess;
struct se_cmd *cmd, *next;
unsigned long flags;
int rc, i;
/*
* Complete outstanding commands with TASK_ABORTED SAM status.
*
* This is following sam4r17, section 5.6 Aborting commands, Table 38
* for TMR LUN_RESET:
*
* a) "Yes" indicates that each command that is aborted on an I_T nexus
* other than the one that caused the SCSI device condition is
* completed with TASK ABORTED status, if the TAS bit is set to one in
* the Control mode page (see SPC-4). "No" indicates that no status is
* returned for aborted commands.
*
* d) If the logical unit reset is caused by a particular I_T nexus
* (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
* (TASK_ABORTED status) applies.
*
* Otherwise (e.g., if triggered by a hard reset), "no"
* (no TASK_ABORTED SAM status) applies.
*
* Note that this seems to be independent of TAS (Task Aborted Status)
* in the Control Mode Page.
*/
for (i = 0; i < dev->queue_cnt; i++) {
flush_work(&dev->queues[i].sq.work);
spin_lock_irqsave(&dev->queues[i].lock, flags);
list_for_each_entry_safe(cmd, next, &dev->queues[i].state_list,
state_list) {
/*
* For PREEMPT_AND_ABORT usage, only process commands
* with a matching reservation key.
*/
if (target_check_cdb_and_preempt(preempt_and_abort_list,
cmd))
continue;
/*
* Not aborting PROUT PREEMPT_AND_ABORT CDB..
*/
if (prout_cmd == cmd)
continue;
sess = cmd->se_sess;
if (WARN_ON_ONCE(!sess))
continue;
spin_lock(&sess->sess_cmd_lock);
rc = __target_check_io_state(cmd, tmr_sess, tas);
spin_unlock(&sess->sess_cmd_lock);
if (!rc)
continue;
list_move_tail(&cmd->state_list, &drain_task_list);
cmd->state_active = false;
}
spin_unlock_irqrestore(&dev->queues[i].lock, flags);
}
if (dev->transport->tmr_notify)
dev->transport->tmr_notify(dev, preempt_and_abort_list ?
TMR_LUN_RESET_PRO : TMR_LUN_RESET,
&drain_task_list);
while (!list_empty(&drain_task_list)) {
cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
list_del_init(&cmd->state_list);
target_show_cmd("LUN_RESET: ", cmd);
pr_debug("LUN_RESET: ITT[0x%08llx] - %s pr_res_key: 0x%016Lx\n",
cmd->tag, (preempt_and_abort_list) ? "preempt" : "",
cmd->pr_res_key);
target_put_cmd_and_wait(cmd);
}
}
int core_tmr_lun_reset(
struct se_device *dev,
struct se_tmr_req *tmr,
struct list_head *preempt_and_abort_list,
struct se_cmd *prout_cmd)
{
struct se_node_acl *tmr_nacl = NULL;
struct se_portal_group *tmr_tpg = NULL;
struct se_session *tmr_sess = NULL;
bool tas;
/*
* TASK_ABORTED status bit, this is configurable via ConfigFS
* struct se_device attributes. spc4r17 section 7.4.6 Control mode page
*
* A task aborted status (TAS) bit set to zero specifies that aborted
* tasks shall be terminated by the device server without any response
* to the application client. A TAS bit set to one specifies that tasks
* aborted by the actions of an I_T nexus other than the I_T nexus on
* which the command was received shall be completed with TASK ABORTED
* status (see SAM-4).
*/
tas = dev->dev_attrib.emulate_tas;
/*
* Determine if this se_tmr is coming from a $FABRIC_MOD
* or struct se_device passthrough..
*/
if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
tmr_sess = tmr->task_cmd->se_sess;
tmr_nacl = tmr_sess->se_node_acl;
tmr_tpg = tmr_sess->se_tpg;
if (tmr_nacl && tmr_tpg) {
pr_debug("LUN_RESET: TMR caller fabric: %s"
" initiator port %s\n",
tmr_tpg->se_tpg_tfo->fabric_name,
tmr_nacl->initiatorname);
}
}
/*
* We only allow one reset or preempt and abort to execute at a time
* to prevent one call from claiming all the cmds causing a second
* call from returning while cmds it should have waited on are still
* running.
*/
mutex_lock(&dev->lun_reset_mutex);
pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
(preempt_and_abort_list) ? "Preempt" : "TMR",
dev->transport->name, tas);
core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
preempt_and_abort_list);
mutex_unlock(&dev->lun_reset_mutex);
/*
* Clear any legacy SPC-2 reservation when called during
* LOGICAL UNIT RESET
*/
if (!preempt_and_abort_list &&
(dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
spin_lock(&dev->dev_reservation_lock);
dev->reservation_holder = NULL;
dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
spin_unlock(&dev->dev_reservation_lock);
pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
}
atomic_long_inc(&dev->num_resets);
pr_debug("LUN_RESET: %s for [%s] Complete\n",
(preempt_and_abort_list) ? "Preempt" : "TMR",
dev->transport->name);
return 0;
}
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