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![Alex Leung](/assets/img/avatar_default.png)
This patch addresses an issue that occurs when an ABTS is received for an se_cmd that completes just before the sess_cmd_list is searched in core_tmr_abort_task(). When the sess_cmd_list is searched, since the ABTS and the FCP_CMND being aborted (that just completed) both have the same OXID, TFO->get_task_tag(TMR) returns a value that matches tmr->ref_task_tag (from TFO->get_task_tag(FCP_CMND)), and the Abort Task tries to abort itself. When this occurs, transport_wait_for_tasks() hangs forever since the TMR is waiting for itself to finish. This patch adds a check to core_tmr_abort_task() to make sure the TMR does not attempt to abort itself. Signed-off-by: Alex Leung <alex.leung@emulex.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
395 lines
11 KiB
C
395 lines
11 KiB
C
/*******************************************************************************
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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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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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 <scsi/scsi.h>
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#include <scsi/scsi_cmnd.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/target_core_configfs.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(
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struct se_tmr_req *tmr)
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{
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struct se_device *dev = tmr->tmr_dev;
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unsigned long flags;
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if (!dev) {
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kfree(tmr);
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return;
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}
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spin_lock_irqsave(&dev->se_tmr_lock, flags);
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list_del(&tmr->tmr_list);
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spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
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kfree(tmr);
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}
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static void core_tmr_handle_tas_abort(
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struct se_node_acl *tmr_nacl,
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struct se_cmd *cmd,
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int tas)
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{
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bool remove = true;
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/*
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* TASK ABORTED status (TAS) bit support
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*/
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if ((tmr_nacl &&
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(tmr_nacl != cmd->se_sess->se_node_acl)) && tas) {
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remove = false;
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transport_send_task_abort(cmd);
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}
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transport_cmd_finish_abort(cmd, remove);
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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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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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struct se_cmd *se_cmd, *tmp_cmd;
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unsigned long flags;
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int ref_tag;
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spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
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list_for_each_entry_safe(se_cmd, tmp_cmd,
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&se_sess->sess_cmd_list, se_cmd_list) {
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if (dev != se_cmd->se_dev)
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continue;
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/* skip se_cmd associated with tmr */
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if (tmr->task_cmd == se_cmd)
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continue;
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ref_tag = se_cmd->se_tfo->get_task_tag(se_cmd);
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if (tmr->ref_task_tag != ref_tag)
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continue;
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printk("ABORT_TASK: Found referenced %s task_tag: %u\n",
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se_cmd->se_tfo->get_fabric_name(), ref_tag);
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spin_lock(&se_cmd->t_state_lock);
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if (se_cmd->transport_state & CMD_T_COMPLETE) {
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printk("ABORT_TASK: ref_tag: %u already complete, skipping\n", ref_tag);
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spin_unlock(&se_cmd->t_state_lock);
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spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
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goto out;
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}
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se_cmd->transport_state |= CMD_T_ABORTED;
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spin_unlock(&se_cmd->t_state_lock);
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list_del_init(&se_cmd->se_cmd_list);
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kref_get(&se_cmd->cmd_kref);
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spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
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cancel_work_sync(&se_cmd->work);
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transport_wait_for_tasks(se_cmd);
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target_put_sess_cmd(se_sess, se_cmd);
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transport_cmd_finish_abort(se_cmd, true);
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printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
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" ref_tag: %d\n", ref_tag);
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tmr->response = TMR_FUNCTION_COMPLETE;
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return;
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}
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spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
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out:
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printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %d\n",
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tmr->ref_task_tag);
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tmr->response = TMR_TASK_DOES_NOT_EXIST;
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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_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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/*
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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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/*
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* Allow the received TMR to return with FUNCTION_COMPLETE.
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*/
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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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* 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 regisration 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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spin_lock(&cmd->t_state_lock);
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if (!(cmd->transport_state & CMD_T_ACTIVE)) {
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spin_unlock(&cmd->t_state_lock);
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continue;
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}
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if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
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spin_unlock(&cmd->t_state_lock);
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continue;
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}
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spin_unlock(&cmd->t_state_lock);
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list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
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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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transport_cmd_finish_abort(cmd, 1);
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}
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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_node_acl *tmr_nacl,
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int 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_cmd *cmd, *next;
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unsigned long flags;
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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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spin_lock_irqsave(&dev->execute_task_lock, flags);
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list_for_each_entry_safe(cmd, next, &dev->state_list, 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, 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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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->execute_task_lock, flags);
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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(&cmd->state_list);
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pr_debug("LUN_RESET: %s cmd: %p"
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" ITT/CmdSN: 0x%08x/0x%08x, i_state: %d, t_state: %d"
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"cdb: 0x%02x\n",
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(preempt_and_abort_list) ? "Preempt" : "", cmd,
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cmd->se_tfo->get_task_tag(cmd), 0,
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cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
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cmd->t_task_cdb[0]);
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pr_debug("LUN_RESET: ITT[0x%08x] - pr_res_key: 0x%016Lx"
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" -- CMD_T_ACTIVE: %d"
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" CMD_T_STOP: %d CMD_T_SENT: %d\n",
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cmd->se_tfo->get_task_tag(cmd), cmd->pr_res_key,
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(cmd->transport_state & CMD_T_ACTIVE) != 0,
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(cmd->transport_state & CMD_T_STOP) != 0,
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(cmd->transport_state & CMD_T_SENT) != 0);
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/*
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* If the command may be queued onto a workqueue cancel it now.
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*
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* This is equivalent to removal from the execute queue in the
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* loop above, but we do it down here given that
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* cancel_work_sync may block.
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*/
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if (cmd->t_state == TRANSPORT_COMPLETE)
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cancel_work_sync(&cmd->work);
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spin_lock_irqsave(&cmd->t_state_lock, flags);
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target_stop_cmd(cmd, &flags);
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cmd->transport_state |= CMD_T_ABORTED;
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spin_unlock_irqrestore(&cmd->t_state_lock, flags);
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core_tmr_handle_tas_abort(tmr_nacl, cmd, tas);
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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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int 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_nacl = tmr->task_cmd->se_sess->se_node_acl;
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tmr_tpg = tmr->task_cmd->se_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->get_fabric_name(),
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tmr_nacl->initiatorname);
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}
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}
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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_nacl, tas,
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preempt_and_abort_list);
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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->dev_reserved_node_acl = 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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