SUNRPC: Fix potential races in xprt_lock_write_next()

We have to ensure that the wake up from the waitqueue and the assignment
of xprt->snd_task are atomic. We can do this by assigning the snd_task
while under the waitqueue spinlock.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index b16243a35f0b..bd337f990a41 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -235,6 +235,9 @@ void		rpc_wake_up_queued_task(struct rpc_wait_queue *,
                                         struct rpc_task *);
 void            rpc_wake_up(struct rpc_wait_queue *);
 struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *);
+struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *,
+                                        bool (*)(struct rpc_task *, void *),
+                                        void *);
 void            rpc_wake_up_status(struct rpc_wait_queue *, int);
 int             rpc_queue_empty(struct rpc_wait_queue *);
 void            rpc_delay(struct rpc_task *, unsigned long);