[PATCH AUTOSEL 5.4 229/330] SUNRPC: Don't start a timer on an already queued rpc task

Sasha Levin
2020-09-18T02:59:39Z

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit 1fab7dc477241c12f977955aa6baea7938b6f08d ]

Move the test for whether a task is already queued to prevent
corruption of the timer list in __rpc_sleep_on_priority_timeout().

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/sunrpc/sched.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 9c79548c68474..53d8b82eda006 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -204,10 +204,6 @@ static void __rpc_add_wait_queue(struct rpc_wait_queue *queue,
struct rpc_task *task,
unsigned char queue_priority)
{
- WARN_ON_ONCE(RPC_IS_QUEUED(task));
- if (RPC_IS_QUEUED(task))
- return;
-
INIT_LIST_HEAD(&task->u.tk_wait.timer_list);
if (RPC_IS_PRIORITY(queue))
__rpc_add_wait_queue_priority(queue, task, queue_priority);
@@ -382,7 +378,7 @@ static void rpc_make_runnable(struct workqueue_struct *wq,
* NB: An RPC task will only receive interrupt-driven events as long
* as it's on a wait queue.
*/
-static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,
+static void __rpc_do_sleep_on_priority(struct rpc_wait_queue *q,
struct rpc_task *task,
unsigned char queue_priority)
{
@@ -395,12 +391,23 @@ static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,

}

+static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,
+ struct rpc_task *task,
+ unsigned char queue_priority)
+{
+ if (WARN_ON_ONCE(RPC_IS_QUEUED(task)))
+ return;
+ __rpc_do_sleep_on_priority(q, task, queue_priority);
+}
+
static void __rpc_sleep_on_priority_timeout(struct rpc_wait_queue *q,
struct rpc_task *task, unsigned long timeout,
unsigned char queue_priority)
{
+ if (WARN_ON_ONCE(RPC_IS_QUEUED(task)))
+ return;
if (time_is_after_jiffies(timeout)) {
- __rpc_sleep_on_priority(q, task, queue_priority);
+ __rpc_do_sleep_on_priority(q, task, queue_priority);
__rpc_add_timer(q, task, timeout);
} else
task->tk_status = -ETIMEDOUT;
--
2.25.1