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@xxxxxx>
---
drivers/target/target_core_device.c | 2
drivers/target/target_core_tmr.c | 54 ----------
drivers/target/target_core_transport.c | 174 +++------------------------------
include/target/target_core_base.h | 13 --
4 files changed, 20 insertions(+), 223 deletions(-)
Index: lio-core/drivers/target/target_core_transport.c
===================================================================
--- lio-core.orig/drivers/target/target_core_transport.c 2012-07-01 14:35:15.774259794 +0200
+++ lio-core/drivers/target/target_core_transport.c 2012-07-01 19:26:09.937488860 +0200
@@ -66,13 +66,11 @@ struct kmem_cache *t10_alua_lu_gp_mem_ca
struct kmem_cache *t10_alua_tg_pt_gp_cache;
struct kmem_cache *t10_alua_tg_pt_gp_mem_cache;
-static int transport_processing_thread(void *param);
static void transport_complete_task_attr(struct se_cmd *cmd);
static void transport_handle_queue_full(struct se_cmd *cmd,
struct se_device *dev);
static int transport_generic_get_mem(struct se_cmd *cmd);
static void transport_put_cmd(struct se_cmd *cmd);
-static void transport_remove_cmd_from_queue(struct se_cmd *cmd);
static int transport_set_sense_codes(struct se_cmd *cmd, u8 asc, u8 ascq);
static void target_complete_ok_work(struct work_struct *work);
@@ -193,14 +191,6 @@ u32 scsi_get_new_index(scsi_index_t type
return new_index;
}
-static void transport_init_queue_obj(struct se_queue_obj *qobj)
-{
- atomic_set(&qobj->queue_cnt, 0);
- INIT_LIST_HEAD(&qobj->qobj_list);
- init_waitqueue_head(&qobj->thread_wq);
- spin_lock_init(&qobj->cmd_queue_lock);
-}
-
void transport_subsystem_check_init(void)
{
int ret;
@@ -560,79 +550,8 @@ void transport_cmd_finish_abort(struct s
if (transport_cmd_check_stop_to_fabric(cmd))
return;
- if (remove) {
- transport_remove_cmd_from_queue(cmd);
+ if (remove)
transport_put_cmd(cmd);
- }
-}
-
-static void transport_add_cmd_to_queue(struct se_cmd *cmd, int t_state,
- bool at_head)
-{
- struct se_device *dev = cmd->se_dev;
- struct se_queue_obj *qobj = &dev->dev_queue_obj;
- unsigned long flags;
-
- if (t_state) {
- spin_lock_irqsave(&cmd->t_state_lock, flags);
- cmd->t_state = t_state;
- cmd->transport_state |= CMD_T_ACTIVE;
- spin_unlock_irqrestore(&cmd->t_state_lock, flags);
- }
-
- spin_lock_irqsave(&qobj->cmd_queue_lock, flags);
-
- /* If the cmd is already on the list, remove it before we add it */
- if (!list_empty(&cmd->se_queue_node))
- list_del(&cmd->se_queue_node);
- else
- atomic_inc(&qobj->queue_cnt);
-
- if (at_head)
- list_add(&cmd->se_queue_node, &qobj->qobj_list);
- else
- list_add_tail(&cmd->se_queue_node, &qobj->qobj_list);
- cmd->transport_state |= CMD_T_QUEUED;
- spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
-
- wake_up_interruptible(&qobj->thread_wq);
-}
-
-static struct se_cmd *
-transport_get_cmd_from_queue(struct se_queue_obj *qobj)
-{
- struct se_cmd *cmd;
- unsigned long flags;
-
- spin_lock_irqsave(&qobj->cmd_queue_lock, flags);
- if (list_empty(&qobj->qobj_list)) {
- spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
- return NULL;
- }
- cmd = list_first_entry(&qobj->qobj_list, struct se_cmd, se_queue_node);
-
- cmd->transport_state &= ~CMD_T_QUEUED;
- list_del_init(&cmd->se_queue_node);
- atomic_dec(&qobj->queue_cnt);
- spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
-
- return cmd;
-}
-
-static void transport_remove_cmd_from_queue(struct se_cmd *cmd)
-{
- struct se_queue_obj *qobj = &cmd->se_dev->dev_queue_obj;
- unsigned long flags;
-
- spin_lock_irqsave(&qobj->cmd_queue_lock, flags);
- if (!(cmd->transport_state & CMD_T_QUEUED)) {
- spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
- return;
- }
- cmd->transport_state &= ~CMD_T_QUEUED;
- atomic_dec(&qobj->queue_cnt);
- list_del_init(&cmd->se_queue_node);
- spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
}
static void target_complete_failure_work(struct work_struct *work)
@@ -1126,7 +1045,6 @@ struct se_device *transport_add_device_t
return NULL;
}
- transport_init_queue_obj(&dev->dev_queue_obj);
dev->dev_flags = device_flags;
dev->dev_status |= TRANSPORT_DEVICE_DEACTIVATED;
dev->dev_ptr = transport_dev;
@@ -1179,10 +1097,10 @@ struct se_device *transport_add_device_t
/*
* Startup the struct se_device processing thread
*/
- dev->process_thread = kthread_run(transport_processing_thread, dev,
- "LIO_%s", dev->transport->name);
- if (IS_ERR(dev->process_thread)) {
- pr_err("Unable to create kthread: LIO_%s\n",
+ dev->tmr_wq = alloc_workqueue("tmr-%s", WQ_MEM_RECLAIM | WQ_UNBOUND, 1,
+ dev->transport->name);
+ if (!dev->tmr_wq) {
+ pr_err("Unable to create tmr workqueue for %s\n",
dev->transport->name);
goto out;
}
@@ -1213,7 +1131,7 @@ struct se_device *transport_add_device_t
return dev;
out:
- kthread_stop(dev->process_thread);
+ destroy_workqueue(dev->tmr_wq);
spin_lock(&hba->device_lock);
list_del(&dev->dev_list);
@@ -1293,7 +1211,6 @@ void transport_init_se_cmd(
INIT_LIST_HEAD(&cmd->se_lun_node);
INIT_LIST_HEAD(&cmd->se_delayed_node);
INIT_LIST_HEAD(&cmd->se_qf_node);
- INIT_LIST_HEAD(&cmd->se_queue_node);
INIT_LIST_HEAD(&cmd->se_cmd_list);
INIT_LIST_HEAD(&cmd->state_list);
init_completion(&cmd->transport_lun_fe_stop_comp);
@@ -1488,10 +1405,9 @@ int transport_handle_cdb_direct(
return -EINVAL;
}
/*
- * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE following
- * transport_generic_handle_cdb*() -> transport_add_cmd_to_queue()
- * in existing usage to ensure that outstanding descriptors are handled
- * correctly during shutdown via transport_wait_for_tasks()
+ * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
+ * outstanding descriptors are handled correctly during shutdown via
+ * transport_wait_for_tasks()
*
* Also, we don't take cmd->t_state_lock here as we only expect
* this to be called for initial descriptor submission.
@@ -1655,18 +1571,6 @@ int target_submit_tmr(struct se_cmd *se_
}
EXPORT_SYMBOL(target_submit_tmr);
-/* transport_generic_handle_tmr():
- *
- *
- */
-int transport_generic_handle_tmr(
- struct se_cmd *cmd)
-{
- transport_add_cmd_to_queue(cmd, TRANSPORT_PROCESS_TMR, false);
- return 0;
-}
-EXPORT_SYMBOL(transport_generic_handle_tmr);
-
/*
* If the cmd is active, request it to be stopped and sleep until it
* has completed.
@@ -2647,8 +2551,6 @@ static int transport_lun_wait_for_tasks(
cmd->transport_state |= CMD_T_LUN_FE_STOP;
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
- wake_up_interruptible(&cmd->se_dev->dev_queue_obj.thread_wq);
-
// XXX: audit task_flags checks.
spin_lock_irqsave(&cmd->t_state_lock, flags);
if ((cmd->transport_state & CMD_T_BUSY) &&
@@ -2667,7 +2569,6 @@ static int transport_lun_wait_for_tasks(
pr_debug("ConfigFS: ITT[0x%08x] - stopped cmd....\n",
cmd->se_tfo->get_task_tag(cmd));
}
- transport_remove_cmd_from_queue(cmd);
return 0;
}
@@ -2866,8 +2767,6 @@ bool transport_wait_for_tasks(struct se_
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
- wake_up_interruptible(&cmd->se_dev->dev_queue_obj.thread_wq);
-
wait_for_completion(&cmd->t_transport_stop_comp);
spin_lock_irqsave(&cmd->t_state_lock, flags);
@@ -3150,8 +3049,9 @@ void transport_send_task_abort(struct se
cmd->se_tfo->queue_status(cmd);
}
-static int transport_generic_do_tmr(struct se_cmd *cmd)
+static void target_tmr_work(struct work_struct *work)
{
+ struct se_cmd *cmd = container_of(work, struct se_cmd, work);
struct se_device *dev = cmd->se_dev;
struct se_tmr_req *tmr = cmd->se_tmr_req;
int ret;
@@ -3187,54 +3087,13 @@ static int transport_generic_do_tmr(stru
cmd->se_tfo->queue_tm_rsp(cmd);
transport_cmd_check_stop_to_fabric(cmd);
- return 0;
}
-/* transport_processing_thread():
- *
- *
- */
-static int transport_processing_thread(void *param)
+int transport_generic_handle_tmr(
+ struct se_cmd *cmd)
{
- int ret;
- struct se_cmd *cmd;
- struct se_device *dev = param;
-
- while (!kthread_should_stop()) {
- ret = wait_event_interruptible(dev->dev_queue_obj.thread_wq,
- atomic_read(&dev->dev_queue_obj.queue_cnt) ||
- kthread_should_stop());
- if (ret < 0)
- goto out;
-
-get_cmd:
- cmd = transport_get_cmd_from_queue(&dev->dev_queue_obj);
- if (!cmd)
- continue;
-
- switch (cmd->t_state) {
- case TRANSPORT_NEW_CMD:
- BUG();
- break;
- case TRANSPORT_PROCESS_TMR:
- transport_generic_do_tmr(cmd);
- break;
- default:
- pr_err("Unknown t_state: %d for ITT: 0x%08x "
- "i_state: %d on SE LUN: %u\n",
- cmd->t_state,
- cmd->se_tfo->get_task_tag(cmd),
- cmd->se_tfo->get_cmd_state(cmd),
- cmd->se_lun->unpacked_lun);
- BUG();
- }
-
- goto get_cmd;
- }
-
-out:
- WARN_ON(!list_empty(&dev->state_list));
- WARN_ON(!list_empty(&dev->dev_queue_obj.qobj_list));
- dev->process_thread = NULL;
+ INIT_WORK(&cmd->work, target_tmr_work);
+ queue_work(cmd->se_dev->tmr_wq, &cmd->work);
return 0;
}
+EXPORT_SYMBOL(transport_generic_handle_tmr);
Index: lio-core/include/target/target_core_base.h
===================================================================
--- lio-core.orig/include/target/target_core_base.h 2012-07-01 14:35:15.777593127 +0200
+++ lio-core/include/target/target_core_base.h 2012-07-01 14:36:41.544259281 +0200
@@ -147,7 +147,6 @@ enum transport_state_table {
TRANSPORT_WRITE_PENDING = 3,
TRANSPORT_PROCESSING = 5,
TRANSPORT_COMPLETE = 6,
- TRANSPORT_PROCESS_TMR = 9,
TRANSPORT_ISTATE_PROCESSING = 11,
TRANSPORT_COMPLETE_QF_WP = 18,
TRANSPORT_COMPLETE_QF_OK = 19,
@@ -464,13 +463,6 @@ struct t10_reservation {
struct t10_reservation_ops pr_ops;
};
-struct se_queue_obj {
- atomic_t queue_cnt;
- spinlock_t cmd_queue_lock;
- struct list_head qobj_list;
- wait_queue_head_t thread_wq;
-};
-
struct se_tmr_req {
/* Task Management function to be performed */
u8 function;
@@ -527,7 +519,6 @@ struct se_cmd {
/* Only used for internal passthrough and legacy TCM fabric modules */
struct se_session *se_sess;
struct se_tmr_req *se_tmr_req;
- struct list_head se_queue_node;
struct list_head se_cmd_list;
struct completion cmd_wait_comp;
struct kref cmd_kref;
@@ -774,7 +765,6 @@ struct se_device {
struct se_obj dev_obj;
struct se_obj dev_access_obj;
struct se_obj dev_export_obj;
- struct se_queue_obj dev_queue_obj;
spinlock_t delayed_cmd_lock;
spinlock_t execute_task_lock;
spinlock_t dev_reservation_lock;
@@ -790,8 +780,7 @@ struct se_device {
struct t10_pr_registration *dev_pr_res_holder;
struct list_head dev_sep_list;
struct list_head dev_tmr_list;
- /* Pointer to descriptor for processing thread */
- struct task_struct *process_thread;
+ struct workqueue_struct *tmr_wq;
struct work_struct qf_work_queue;
struct list_head delayed_cmd_list;
struct list_head state_list;
Index: lio-core/drivers/target/target_core_tmr.c
===================================================================
--- lio-core.orig/drivers/target/target_core_tmr.c 2012-07-01 14:28:56.930928723 +0200
+++ lio-core/drivers/target/target_core_tmr.c 2012-07-01 14:36:41.000000000 +0200
@@ -351,57 +351,6 @@ static void core_tmr_drain_state_list(
}
}
-static void core_tmr_drain_cmd_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_cmd_list);
- struct se_queue_obj *qobj = &dev->dev_queue_obj;
- struct se_cmd *cmd, *tcmd;
- unsigned long flags;
-
- /*
- * Release all commands remaining in the per-device command queue.
- *
- * This follows the same logic as above for the state list.
- */
- spin_lock_irqsave(&qobj->cmd_queue_lock, flags);
- list_for_each_entry_safe(cmd, tcmd, &qobj->qobj_list, se_queue_node) {
- /*
- * 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;
-
- cmd->transport_state &= ~CMD_T_QUEUED;
- atomic_dec(&qobj->queue_cnt);
- list_move_tail(&cmd->se_queue_node, &drain_cmd_list);
- }
- spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
-
- while (!list_empty(&drain_cmd_list)) {
- cmd = list_entry(drain_cmd_list.next, struct se_cmd, se_queue_node);
- list_del_init(&cmd->se_queue_node);
-
- pr_debug("LUN_RESET: %s from Device Queue: cmd: %p t_state:"
- " %d t_fe_count: %d\n", (preempt_and_abort_list) ?
- "Preempt" : "", cmd, cmd->t_state,
- atomic_read(&cmd->t_fe_count));
-
- core_tmr_handle_tas_abort(tmr_nacl, cmd, tas,
- atomic_read(&cmd->t_fe_count));
- }
-}
-
int core_tmr_lun_reset(
struct se_device *dev,
struct se_tmr_req *tmr,
@@ -444,8 +393,7 @@ int core_tmr_lun_reset(
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);
- core_tmr_drain_cmd_list(dev, prout_cmd, tmr_nacl, tas,
- preempt_and_abort_list);
+
/*
* Clear any legacy SPC-2 reservation when called during
* LOGICAL UNIT RESET
Index: lio-core/drivers/target/target_core_device.c
===================================================================
--- lio-core.orig/drivers/target/target_core_device.c 2012-07-01 14:28:56.930928723 +0200
+++ lio-core/drivers/target/target_core_device.c 2012-07-01 14:36:41.544259281 +0200
@@ -715,7 +715,7 @@ void se_release_device_for_hba(struct se
se_dev_stop(dev);
if (dev->dev_ptr) {
- kthread_stop(dev->process_thread);
+ destroy_workqueue(dev->tmr_wq);
if (dev->transport->free_device)
dev->transport->free_device(dev->dev_ptr);
}
--
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