Target drivers must call target_sess_cmd_list_set_waiting() and target_wait_for_sess_cmds() before freeing a session. Instead of setting a flag in each pending command from the former function and waiting in the latter function on a per-command completion, only set a per-session flag in the former function and wait on a per-session completion in the latter function. This patch is based on the following two patches: * Bart Van Assche, target: Simplify session shutdown code, February 19, 2015 (https://github.com/bvanassche/linux/commit/8df5463d7d7619f2f1b70cfe5172eaef0aa52815). * Christoph Hellwig, target: Rework session shutdown code, December 7, 2015 (http://thread.gmane.org/gmane.linux.scsi.target.devel/10695). Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> --- drivers/target/target_core_transport.c | 74 ++++++++++++---------------------- include/target/target_core_base.h | 4 +- 2 files changed, 27 insertions(+), 51 deletions(-) diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 07598fb..331ca6a 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -237,8 +237,8 @@ struct se_session *transport_init_session(enum target_prot_op sup_prot_ops) INIT_LIST_HEAD(&se_sess->sess_list); INIT_LIST_HEAD(&se_sess->sess_acl_list); INIT_LIST_HEAD(&se_sess->sess_cmd_list); - INIT_LIST_HEAD(&se_sess->sess_wait_list); spin_lock_init(&se_sess->sess_cmd_lock); + init_waitqueue_head(&se_sess->cmd_list_wq); kref_init(&se_sess->sess_kref); kref_init(&se_sess->kref2); kref_get(&se_sess->kref2); @@ -1201,7 +1201,6 @@ void transport_init_se_cmd( INIT_LIST_HEAD(&cmd->se_qf_node); INIT_LIST_HEAD(&cmd->se_cmd_list); INIT_LIST_HEAD(&cmd->state_list); - init_completion(&cmd->cmd_wait_comp); init_completion(&cmd->finished); spin_lock_init(&cmd->t_state_lock); kref_init(&cmd->cmd_kref); @@ -2501,17 +2500,11 @@ static void target_release_cmd_kref(struct kref *kref) se_cmd->tag); spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); - if (list_empty(&se_cmd->se_cmd_list)) { - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); - se_cmd->se_tfo->release_cmd(se_cmd); - return; - } - if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) { - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); - complete(&se_cmd->cmd_wait_comp); - return; + if (likely(!list_empty(&se_cmd->se_cmd_list))) { + list_del(&se_cmd->se_cmd_list); + if (list_empty(&se_sess->sess_cmd_list)) + wake_up(&se_sess->cmd_list_wq); } - list_del(&se_cmd->se_cmd_list); spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); se_cmd->se_tfo->release_cmd(se_cmd); @@ -2532,59 +2525,44 @@ int target_put_sess_cmd(struct se_cmd *se_cmd) } EXPORT_SYMBOL(target_put_sess_cmd); -/* target_sess_cmd_list_set_waiting - Flag all commands in - * sess_cmd_list to complete cmd_wait_comp. Set - * sess_tearing_down so no more commands are queued. +/** + * target_sess_cmd_list_set_waiting - Prevent new commands to be queued * @se_sess: session to flag */ void target_sess_cmd_list_set_waiting(struct se_session *se_sess) { - struct se_cmd *se_cmd; unsigned long flags; spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); - if (se_sess->sess_tearing_down) { - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); - return; - } se_sess->sess_tearing_down = 1; - list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list); - - list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list) - se_cmd->cmd_wait_set = 1; - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); } EXPORT_SYMBOL(target_sess_cmd_list_set_waiting); -/* target_wait_for_sess_cmds - Wait for outstanding descriptors +/** + * target_wait_for_sess_cmds - Wait for outstanding commands * @se_sess: session to wait for active I/O */ void target_wait_for_sess_cmds(struct se_session *se_sess) { - struct se_cmd *se_cmd, *tmp_cmd; - unsigned long flags; - - list_for_each_entry_safe(se_cmd, tmp_cmd, - &se_sess->sess_wait_list, se_cmd_list) { - list_del(&se_cmd->se_cmd_list); - - pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:" - " %d\n", se_cmd, se_cmd->t_state, - se_cmd->se_tfo->get_cmd_state(se_cmd)); - - wait_for_completion(&se_cmd->cmd_wait_comp); - pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d" - " fabric state: %d\n", se_cmd, se_cmd->t_state, - se_cmd->se_tfo->get_cmd_state(se_cmd)); - - se_cmd->se_tfo->release_cmd(se_cmd); - } - - spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); - WARN_ON(!list_empty(&se_sess->sess_cmd_list)); - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + struct se_cmd *cmd; + int ret; + WARN_ON_ONCE(!se_sess->sess_tearing_down); + + spin_lock_irq(&se_sess->sess_cmd_lock); + do { + ret = wait_event_interruptible_lock_irq_timeout( + se_sess->cmd_list_wq, + list_empty(&se_sess->sess_cmd_list), + se_sess->sess_cmd_lock, 180 * HZ); + list_for_each_entry(cmd, &se_sess->sess_cmd_list, se_cmd_list) + pr_debug("%s: ITT %#llx dir %d i_state %d t_state %d len %d\n", + __func__, cmd->tag, cmd->data_direction, + cmd->se_tfo->get_cmd_state(cmd), cmd->t_state, + cmd->data_length); + } while (ret <= 0); + spin_unlock_irq(&se_sess->sess_cmd_lock); } EXPORT_SYMBOL(target_wait_for_sess_cmds); diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index 4e22424..80c4cbe 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -442,7 +442,6 @@ struct se_cmd { u8 scsi_asc; u8 scsi_ascq; u16 scsi_sense_length; - unsigned cmd_wait_set:1; unsigned unknown_data_length:1; bool state_active:1; bool send_abort_response:1; @@ -475,7 +474,6 @@ struct se_cmd { struct se_session *se_sess; struct se_tmr_req *se_tmr_req; struct list_head se_cmd_list; - struct completion cmd_wait_comp; const struct target_core_fabric_ops *se_tfo; sense_reason_t (*execute_cmd)(struct se_cmd *); sense_reason_t (*transport_complete_callback)(struct se_cmd *, bool, int *); @@ -607,8 +605,8 @@ struct se_session { struct list_head sess_list; struct list_head sess_acl_list; struct list_head sess_cmd_list; - struct list_head sess_wait_list; spinlock_t sess_cmd_lock; + wait_queue_head_t cmd_list_wq; struct kref sess_kref; struct kref kref2; void *sess_cmd_map; -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe target-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
