linux/drivers/target/target_core_tmr.c
Christoph Hellwig af8772926f target: replace the processing thread with a TMR work queue
The last functionality of the target processing thread is offloading possibly
long running task management requests from the submitter context.  To keep
TMR semantics the same we need a single threaded ordered queue, which can
be provided by a per-device workqueue with the right flags.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-07-16 17:35:21 -07:00

420 lines
12 KiB
C

/*******************************************************************************
* Filename: target_core_tmr.c
*
* This file contains SPC-3 task management infrastructure
*
* Copyright (c) 2009,2010 Rising Tide Systems
* Copyright (c) 2009,2010 Linux-iSCSI.org
*
* Nicholas A. Bellinger <nab@kernel.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
******************************************************************************/
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/export.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <target/target_core_base.h>
#include <target/target_core_backend.h>
#include <target/target_core_fabric.h>
#include <target/target_core_configfs.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)
{
struct se_device *dev = tmr->tmr_dev;
unsigned long flags;
if (!dev) {
kfree(tmr);
return;
}
spin_lock_irqsave(&dev->se_tmr_lock, flags);
list_del(&tmr->tmr_list);
spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
kfree(tmr);
}
static void core_tmr_handle_tas_abort(
struct se_node_acl *tmr_nacl,
struct se_cmd *cmd,
int tas,
int fe_count)
{
if (!fe_count) {
transport_cmd_finish_abort(cmd, 1);
return;
}
/*
* TASK ABORTED status (TAS) bit support
*/
if ((tmr_nacl &&
(tmr_nacl == cmd->se_sess->se_node_acl)) || tas)
transport_send_task_abort(cmd);
transport_cmd_finish_abort(cmd, 0);
}
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;
}
void core_tmr_abort_task(
struct se_device *dev,
struct se_tmr_req *tmr,
struct se_session *se_sess)
{
struct se_cmd *se_cmd, *tmp_cmd;
unsigned long flags;
int ref_tag;
spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
list_for_each_entry_safe(se_cmd, tmp_cmd,
&se_sess->sess_cmd_list, se_cmd_list) {
if (dev != se_cmd->se_dev)
continue;
ref_tag = se_cmd->se_tfo->get_task_tag(se_cmd);
if (tmr->ref_task_tag != ref_tag)
continue;
printk("ABORT_TASK: Found referenced %s task_tag: %u\n",
se_cmd->se_tfo->get_fabric_name(), ref_tag);
spin_lock_irq(&se_cmd->t_state_lock);
if (se_cmd->transport_state & CMD_T_COMPLETE) {
printk("ABORT_TASK: ref_tag: %u already complete, skipping\n", ref_tag);
spin_unlock_irq(&se_cmd->t_state_lock);
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
goto out;
}
se_cmd->transport_state |= CMD_T_ABORTED;
spin_unlock_irq(&se_cmd->t_state_lock);
list_del_init(&se_cmd->se_cmd_list);
kref_get(&se_cmd->cmd_kref);
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
cancel_work_sync(&se_cmd->work);
transport_wait_for_tasks(se_cmd);
/*
* Now send SAM_STAT_TASK_ABORTED status for the referenced
* se_cmd descriptor..
*/
transport_send_task_abort(se_cmd);
/*
* Also deal with possible extra acknowledge reference..
*/
if (se_cmd->se_cmd_flags & SCF_ACK_KREF)
target_put_sess_cmd(se_sess, se_cmd);
target_put_sess_cmd(se_sess, se_cmd);
printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
" ref_tag: %d\n", ref_tag);
tmr->response = TMR_FUNCTION_COMPLETE;
return;
}
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
out:
printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %d\n",
tmr->ref_task_tag);
tmr->response = TMR_TASK_DOES_NOT_EXIST;
}
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_tmr_req *tmr_p, *tmr_pp;
struct se_cmd *cmd;
unsigned long flags;
/*
* 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) {
/*
* Allow the received TMR to return with FUNCTION_COMPLETE.
*/
if (tmr_p == tmr)
continue;
cmd = tmr_p->task_cmd;
if (!cmd) {
pr_err("Unable to locate struct se_cmd for TMR\n");
continue;
}
/*
* If this function was called with a valid pr_res_key
* parameter (eg: for PROUT PREEMPT_AND_ABORT service action
* skip non regisration key matching TMRs.
*/
if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
continue;
spin_lock(&cmd->t_state_lock);
if (!(cmd->transport_state & CMD_T_ACTIVE)) {
spin_unlock(&cmd->t_state_lock);
continue;
}
if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
spin_unlock(&cmd->t_state_lock);
continue;
}
spin_unlock(&cmd->t_state_lock);
list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
}
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);
transport_cmd_finish_abort(cmd, 1);
}
}
static void core_tmr_drain_state_list(
struct se_device *dev,
struct se_cmd *prout_cmd,
struct se_node_acl *tmr_nacl,
int tas,
struct list_head *preempt_and_abort_list)
{
LIST_HEAD(drain_task_list);
struct se_cmd *cmd, *next;
unsigned long flags;
int fe_count;
/*
* 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.
*/
spin_lock_irqsave(&dev->execute_task_lock, flags);
list_for_each_entry_safe(cmd, next, &dev->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;
list_move_tail(&cmd->state_list, &drain_task_list);
cmd->state_active = false;
}
spin_unlock_irqrestore(&dev->execute_task_lock, flags);
while (!list_empty(&drain_task_list)) {
cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
list_del(&cmd->state_list);
pr_debug("LUN_RESET: %s cmd: %p"
" ITT/CmdSN: 0x%08x/0x%08x, i_state: %d, t_state: %d"
"cdb: 0x%02x\n",
(preempt_and_abort_list) ? "Preempt" : "", cmd,
cmd->se_tfo->get_task_tag(cmd), 0,
cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
cmd->t_task_cdb[0]);
pr_debug("LUN_RESET: ITT[0x%08x] - pr_res_key: 0x%016Lx"
" -- CMD_T_ACTIVE: %d"
" CMD_T_STOP: %d CMD_T_SENT: %d\n",
cmd->se_tfo->get_task_tag(cmd), cmd->pr_res_key,
(cmd->transport_state & CMD_T_ACTIVE) != 0,
(cmd->transport_state & CMD_T_STOP) != 0,
(cmd->transport_state & CMD_T_SENT) != 0);
/*
* If the command may be queued onto a workqueue cancel it now.
*
* This is equivalent to removal from the execute queue in the
* loop above, but we do it down here given that
* cancel_work_sync may block.
*/
if (cmd->t_state == TRANSPORT_COMPLETE)
cancel_work_sync(&cmd->work);
spin_lock_irqsave(&cmd->t_state_lock, flags);
target_stop_cmd(cmd, &flags);
fe_count = atomic_read(&cmd->t_fe_count);
if (!(cmd->transport_state & CMD_T_ACTIVE)) {
pr_debug("LUN_RESET: got CMD_T_ACTIVE for"
" cdb: %p, t_fe_count: %d dev: %p\n", cmd,
fe_count, dev);
cmd->transport_state |= CMD_T_ABORTED;
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
core_tmr_handle_tas_abort(tmr_nacl, cmd, tas, fe_count);
continue;
}
pr_debug("LUN_RESET: Got !CMD_T_ACTIVE for cdb: %p,"
" t_fe_count: %d dev: %p\n", cmd, fe_count, dev);
cmd->transport_state |= CMD_T_ABORTED;
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
core_tmr_handle_tas_abort(tmr_nacl, cmd, tas, fe_count);
}
}
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;
int 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->se_sub_dev->se_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_nacl = tmr->task_cmd->se_sess->se_node_acl;
tmr_tpg = tmr->task_cmd->se_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->get_fabric_name(),
tmr_nacl->initiatorname);
}
}
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_nacl, tas,
preempt_and_abort_list);
/*
* Clear any legacy SPC-2 reservation when called during
* LOGICAL UNIT RESET
*/
if (!preempt_and_abort_list &&
(dev->dev_flags & DF_SPC2_RESERVATIONS)) {
spin_lock(&dev->dev_reservation_lock);
dev->dev_reserved_node_acl = NULL;
dev->dev_flags &= ~DF_SPC2_RESERVATIONS;
spin_unlock(&dev->dev_reservation_lock);
pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
}
spin_lock_irq(&dev->stats_lock);
dev->num_resets++;
spin_unlock_irq(&dev->stats_lock);
pr_debug("LUN_RESET: %s for [%s] Complete\n",
(preempt_and_abort_list) ? "Preempt" : "TMR",
dev->transport->name);
return 0;
}