rfkill: fix rfkill_fop_read wait_event usage

[pandora-kernel.git] / net / sunrpc / sched.c

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 56c3f85..206c61e 100644 (file)
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -139,6 +139,8 @@ static void __rpc_add_wait_queue(struct rpc_wait_queue *queue,
                list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
        task->tk_waitqueue = queue;
        queue->qlen++;
+       /* barrier matches the read in rpc_wake_up_task_queue_locked() */
+       smp_wmb();
        rpc_set_queued(task);
 
        dprintk("RPC: %5u added to queue %p \"%s\"\n",
@@ -294,13 +296,20 @@ EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task);
 /*
  * Make an RPC task runnable.
  *
- * Note: If the task is ASYNC, this must be called with
- * the spinlock held to protect the wait queue operation.
+ * Note: If the task is ASYNC, and is being made runnable after sitting on an
+ * rpc_wait_queue, this must be called with the queue spinlock held to protect
+ * the wait queue operation.
+ * Note the ordering of rpc_test_and_set_running() and rpc_clear_queued(),
+ * which is needed to ensure that __rpc_execute() doesn't loop (due to the
+ * lockless RPC_IS_QUEUED() test) before we've had a chance to test
+ * the RPC_TASK_RUNNING flag.
  */
 static void rpc_make_runnable(struct rpc_task *task)
 {
+       bool need_wakeup = !rpc_test_and_set_running(task);
+
        rpc_clear_queued(task);
-       if (rpc_test_and_set_running(task))
+       if (!need_wakeup)
                return;
        if (RPC_IS_ASYNC(task)) {
                INIT_WORK(&task->u.tk_work, rpc_async_schedule);
@@ -389,8 +398,11 @@ static void __rpc_do_wake_up_task(struct rpc_wait_queue *queue, struct rpc_task
  */
 static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct rpc_task *task)
 {
-       if (RPC_IS_QUEUED(task) && task->tk_waitqueue == queue)
-               __rpc_do_wake_up_task(queue, task);
+       if (RPC_IS_QUEUED(task)) {
+               smp_rmb();
+               if (task->tk_waitqueue == queue)
+                       __rpc_do_wake_up_task(queue, task);
+       }
 }
 
 /*
@@ -918,8 +930,7 @@ static void rpc_async_release(struct work_struct *work)
 
 static void rpc_release_resources_task(struct rpc_task *task)
 {
-       if (task->tk_rqstp)
-               xprt_release(task);
+       xprt_release(task);
        if (task->tk_msg.rpc_cred) {
                put_rpccred(task->tk_msg.rpc_cred);
                task->tk_msg.rpc_cred = NULL;