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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 88dcd2dab5
    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: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger 2015-07-23 22:30:31 +00:00
parent e54198657b
commit 007d038bdf
1 changed files with 16 additions and 2 deletions
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18
drivers/target/iscsi/iscsi_target.c
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@ -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);