[3.13.y.z extended stable] Patch "target: Use complete_all for se_cmd->t_transport_stop_comp" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    target: Use complete_all for se_cmd->t_transport_stop_comp

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.5.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 0d577e67bb58c63e5d36381b2dc59beae43f7212 Mon Sep 17 00:00:00 2001
From: Nicholas Bellinger <nab at linux-iscsi.org>
Date: Mon, 9 Jun 2014 23:36:51 +0000
Subject: target: Use complete_all for se_cmd->t_transport_stop_comp

commit a95d6511303b848da45ee27b35018bb58087bdc6 upstream.

This patch fixes a bug where multiple waiters on ->t_transport_stop_comp
occurs due to a concurrent ABORT_TASK and session reset both invoking
transport_wait_for_tasks(), while waiting for the associated se_cmd
descriptor backend processing to complete.

For this case, complete_all() should be invoked in order to wake up
both waiters in core_tmr_abort_task() + transport_generic_free_cmd()
process contexts.

Cc: Thomas Glanzmann <thomas at glanzmann.de>
Cc: Charalampos Pournaris <charpour at gmail.com>
Signed-off-by: Nicholas Bellinger <nab at linux-iscsi.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/target/target_core_transport.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 453690f..31adaac 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -534,7 +534,7 @@ static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists,

 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);

-		complete(&cmd->t_transport_stop_comp);
+		complete_all(&cmd->t_transport_stop_comp);
 		return 1;
 	}

@@ -653,7 +653,7 @@ void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
 	if (cmd->transport_state & CMD_T_ABORTED &&
 	    cmd->transport_state & CMD_T_STOP) {
 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
-		complete(&cmd->t_transport_stop_comp);
+		complete_all(&cmd->t_transport_stop_comp);
 		return;
 	} else if (cmd->transport_state & CMD_T_FAILED) {
 		INIT_WORK(&cmd->work, target_complete_failure_work);
@@ -1710,7 +1710,7 @@ void target_execute_cmd(struct se_cmd *cmd)
 			cmd->se_tfo->get_task_tag(cmd));

 		spin_unlock_irq(&cmd->t_state_lock);
-		complete(&cmd->t_transport_stop_comp);
+		complete_all(&cmd->t_transport_stop_comp);
 		return;
 	}

--
1.9.1