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Commit 007d038b authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

iscsi-target: Fix iser explicit logout TX kthread leak 



This patch fixes a regression introduced with the following commit
in v4.0-rc1 code, where an explicit iser-target logout would result
in ->tx_thread_active being incorrectly cleared by the logout post
handler, and subsequent TX kthread leak:

    commit 88dcd2da
    Author: Nicholas Bellinger <nab@linux-iscsi.org>
    Date:   Thu Feb 26 22:19:15 2015 -0800

        iscsi-target: Convert iscsi_thread_set usage to kthread.h

To address this bug, change iscsit_logout_post_handler_closesession()
and iscsit_logout_post_handler_samecid() to only cmpxchg() on
->tx_thread_active for traditional iscsi/tcp connections.

This is required because iscsi/tcp connections are invoking logout
post handler logic directly from TX kthread context, while iser
connections are invoking logout post handler logic from a seperate
workqueue context.

Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent e5419865

drivers/target/iscsi/iscsi_target.c

+16 −2
Original line number Diff line number Diff line
@@ -4544,7 +4544,18 @@ static void iscsit_logout_post_handler_closesession( 
	struct iscsi_conn *conn)

{

	struct iscsi_session *sess = conn->sess;

	int sleep = cmpxchg(&conn->tx_thread_active, true, false);

	int sleep = 1;

	/*

	 * Traditional iscsi/tcp will invoke this logic from TX thread

	 * context during session logout, so clear tx_thread_active and

	 * sleep if iscsit_close_connection() has not already occured.

	 *

	 * Since iser-target invokes this logic from it's own workqueue,

	 * always sleep waiting for RX/TX thread shutdown to complete

	 * within iscsit_close_connection().

	 */

	if (conn->conn_transport->transport_type == ISCSI_TCP)

		sleep = cmpxchg(&conn->tx_thread_active, true, false);



	atomic_set(&conn->conn_logout_remove, 0);

	complete(&conn->conn_logout_comp);
@@ -4558,7 +4569,10 @@ static void iscsit_logout_post_handler_closesession( 
static void iscsit_logout_post_handler_samecid(

	struct iscsi_conn *conn)

{

	int sleep = cmpxchg(&conn->tx_thread_active, true, false);

	int sleep = 1;



	if (conn->conn_transport->transport_type == ISCSI_TCP)

		sleep = cmpxchg(&conn->tx_thread_active, true, false);



	atomic_set(&conn->conn_logout_remove, 0);

	complete(&conn->conn_logout_comp);