From 00d909a10710a3416272d4179adf3837b9a9f3c2 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 22 Jun 2018 14:52:53 -0700 Subject: scsi: target: Make the session shutdown code also wait for commands that are being aborted Target drivers must call target_sess_cmd_list_set_waiting() and target_wait_for_sess_cmds() before freeing a session. Since freeing a session is only safe after all commands that are associated with a session have finished, make target_wait_for_sess_cmds() also wait for commands that are being aborted. Instead of setting a flag in each pending command from target_sess_cmd_list_set_waiting() and waiting in target_wait_for_sess_cmds() 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 change is safe because once a SCSI initiator system has submitted a command a target system is always allowed to execute it to completion. See also commit 0f4a943168f3 ("target: Fix remote-port TMR ABORT + se_cmd fabric stop"). 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 Reviewed-by: Mike Christie Cc: Hannes Reinecke Cc: Christoph Hellwig Cc: Sagi Grimberg Signed-off-by: Martin K. Petersen --- drivers/target/target_core_tmr.c | 5 +-- drivers/target/target_core_transport.c | 77 ++++++++++------------------------ include/target/target_core_base.h | 3 +- 3 files changed, 24 insertions(+), 61 deletions(-) diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c index 9c7bc1ca341a..da8125dd3a4c 100644 --- a/drivers/target/target_core_tmr.c +++ b/drivers/target/target_core_tmr.c @@ -142,7 +142,7 @@ static bool __target_check_io_state(struct se_cmd *se_cmd, return false; } } - if (sess->sess_tearing_down || se_cmd->cmd_wait_set) { + if (sess->sess_tearing_down) { pr_debug("Attempted to abort io tag: %llu already shutdown," " skipping\n", se_cmd->tag); spin_unlock(&se_cmd->t_state_lock); @@ -187,7 +187,6 @@ void core_tmr_abort_task( if (!__target_check_io_state(se_cmd, se_sess, 0)) continue; - list_del_init(&se_cmd->se_cmd_list); spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); cancel_work_sync(&se_cmd->work); @@ -259,7 +258,7 @@ static void core_tmr_drain_tmr_list( spin_unlock(&sess->sess_cmd_lock); continue; } - if (sess->sess_tearing_down || cmd->cmd_wait_set) { + if (sess->sess_tearing_down) { spin_unlock(&cmd->t_state_lock); spin_unlock(&sess->sess_cmd_lock); continue; diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 595b2f12ca6a..087dddfc5c35 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -235,8 +235,8 @@ void transport_init_session(struct se_session *se_sess) 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); } EXPORT_SYMBOL(transport_init_session); @@ -2728,13 +2728,15 @@ static void target_release_cmd_kref(struct kref *kref) if (se_sess) { spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); list_del_init(&se_cmd->se_cmd_list); + if (list_empty(&se_sess->sess_cmd_list)) + wake_up(&se_sess->cmd_list_wq); spin_lock(&se_cmd->t_state_lock); fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP) && (se_cmd->transport_state & CMD_T_ABORTED); spin_unlock(&se_cmd->t_state_lock); - if (se_cmd->cmd_wait_set || fabric_stop) { + if (fabric_stop) { spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); target_free_cmd_mem(se_cmd); complete(&se_cmd->cmd_wait_comp); @@ -2863,78 +2865,41 @@ void target_show_cmd(const char *pfx, struct se_cmd *cmd) EXPORT_SYMBOL(target_show_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 - Set sess_tearing_down so no new commands are queued. * @se_sess: session to flag */ void target_sess_cmd_list_set_waiting(struct se_session *se_sess) { - struct se_cmd *se_cmd, *tmp_cmd; unsigned long flags; - int rc; 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_safe(se_cmd, tmp_cmd, - &se_sess->sess_wait_list, se_cmd_list) { - rc = kref_get_unless_zero(&se_cmd->cmd_kref); - if (rc) { - se_cmd->cmd_wait_set = 1; - spin_lock(&se_cmd->t_state_lock); - se_cmd->transport_state |= CMD_T_FABRIC_STOP; - spin_unlock(&se_cmd->t_state_lock); - } else - list_del_init(&se_cmd->se_cmd_list); - } - 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; - bool tas; - - list_for_each_entry_safe(se_cmd, tmp_cmd, - &se_sess->sess_wait_list, 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)); - - spin_lock_irqsave(&se_cmd->t_state_lock, flags); - tas = (se_cmd->transport_state & CMD_T_TAS); - spin_unlock_irqrestore(&se_cmd->t_state_lock, flags); - - if (!target_put_sess_cmd(se_cmd)) { - if (tas) - target_put_sess_cmd(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) + target_show_cmd("session shutdown: still waiting for ", + cmd); + } 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 448f291125c2..906c1fc485e4 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -443,7 +443,6 @@ 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; u64 tag; /* SAM command identifier aka task tag */ @@ -606,8 +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; void *sess_cmd_map; struct sbitmap_queue sess_tag_pool; }; -- cgit v1.2.3-59-g8ed1b