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