diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/target/target_core_transport.c | 40 |
1 files changed, 24 insertions, 16 deletions
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 7c2def7e2593..46e25118ab25 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -68,7 +68,7 @@ struct kmem_cache *t10_alua_tg_pt_gp_mem_cache; static int transport_generic_write_pending(struct se_cmd *); static int transport_processing_thread(void *param); -static int __transport_execute_tasks(struct se_device *dev); +static int __transport_execute_tasks(struct se_device *dev, struct se_cmd *); static void transport_complete_task_attr(struct se_cmd *cmd); static void transport_handle_queue_full(struct se_cmd *cmd, struct se_device *dev); @@ -851,13 +851,11 @@ static void transport_add_tasks_to_state_queue(struct se_cmd *cmd) spin_unlock_irqrestore(&cmd->t_state_lock, flags); } -static void transport_add_tasks_from_cmd(struct se_cmd *cmd) +static void __transport_add_tasks_from_cmd(struct se_cmd *cmd) { struct se_device *dev = cmd->se_dev; struct se_task *task, *task_prev = NULL; - unsigned long flags; - spin_lock_irqsave(&dev->execute_task_lock, flags); list_for_each_entry(task, &cmd->t_task_list, t_list) { if (!list_empty(&task->t_execute_list)) continue; @@ -868,6 +866,15 @@ static void transport_add_tasks_from_cmd(struct se_cmd *cmd) __transport_add_task_to_execute_queue(task, task_prev, dev); task_prev = task; } +} + +static void transport_add_tasks_from_cmd(struct se_cmd *cmd) +{ + unsigned long flags; + struct se_device *dev = cmd->se_dev; + + spin_lock_irqsave(&dev->execute_task_lock, flags); + __transport_add_tasks_from_cmd(cmd); spin_unlock_irqrestore(&dev->execute_task_lock, flags); } @@ -2075,19 +2082,16 @@ static int transport_execute_tasks(struct se_cmd *cmd) if (!add_tasks) goto execute_tasks; /* - * This calls transport_add_tasks_from_cmd() to handle - * HEAD_OF_QUEUE ordering for SAM Task Attribute emulation - * (if enabled) in __transport_add_task_to_execute_queue() and - * transport_add_task_check_sam_attr(). + * __transport_execute_tasks() -> __transport_add_tasks_from_cmd() + * adds associated se_tasks while holding dev->execute_task_lock + * before I/O dispath to avoid a double spinlock access. */ - transport_add_tasks_from_cmd(cmd); + __transport_execute_tasks(se_dev, cmd); + return 0; } - /* - * Kick the execution queue for the cmd associated struct se_device - * storage object. - */ + execute_tasks: - __transport_execute_tasks(se_dev); + __transport_execute_tasks(se_dev, NULL); return 0; } @@ -2097,7 +2101,7 @@ execute_tasks: * * Called from transport_processing_thread() */ -static int __transport_execute_tasks(struct se_device *dev) +static int __transport_execute_tasks(struct se_device *dev, struct se_cmd *new_cmd) { int error; struct se_cmd *cmd = NULL; @@ -2106,6 +2110,9 @@ static int __transport_execute_tasks(struct se_device *dev) check_depth: spin_lock_irq(&dev->execute_task_lock); + if (new_cmd != NULL) + __transport_add_tasks_from_cmd(new_cmd); + if (list_empty(&dev->execute_task_list)) { spin_unlock_irq(&dev->execute_task_lock); return 0; @@ -2139,6 +2146,7 @@ check_depth: transport_generic_request_failure(cmd); } + new_cmd = NULL; goto check_depth; return 0; @@ -4647,7 +4655,7 @@ static int transport_processing_thread(void *param) goto out; get_cmd: - __transport_execute_tasks(dev); + __transport_execute_tasks(dev, NULL); cmd = transport_get_cmd_from_queue(&dev->dev_queue_obj); if (!cmd) |