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-rw-r--r--net/sunrpc/sched.c33
1 files changed, 20 insertions, 13 deletions
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 385f427..ff50a05 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -293,11 +293,6 @@ static void rpc_make_runnable(struct rpc_task *task)
rpc_clear_queued(task);
if (rpc_test_and_set_running(task))
return;
- /* We might have raced */
- if (RPC_IS_QUEUED(task)) {
- rpc_clear_running(task);
- return;
- }
if (RPC_IS_ASYNC(task)) {
int status;
@@ -607,7 +602,9 @@ void rpc_release_calldata(const struct rpc_call_ops *ops, void *calldata)
*/
static void __rpc_execute(struct rpc_task *task)
{
- int status = 0;
+ struct rpc_wait_queue *queue;
+ int task_is_async = RPC_IS_ASYNC(task);
+ int status = 0;
dprintk("RPC: %5u __rpc_execute flags=0x%x\n",
task->tk_pid, task->tk_flags);
@@ -647,15 +644,25 @@ static void __rpc_execute(struct rpc_task *task)
*/
if (!RPC_IS_QUEUED(task))
continue;
- rpc_clear_running(task);
- if (RPC_IS_ASYNC(task)) {
- /* Careful! we may have raced... */
- if (RPC_IS_QUEUED(task))
- return;
- if (rpc_test_and_set_running(task))
- return;
+ /*
+ * The queue->lock protects against races with
+ * rpc_make_runnable().
+ *
+ * Note that once we clear RPC_TASK_RUNNING on an asynchronous
+ * rpc_task, rpc_make_runnable() can assign it to a
+ * different workqueue. We therefore cannot assume that the
+ * rpc_task pointer may still be dereferenced.
+ */
+ queue = task->tk_waitqueue;
+ spin_lock_bh(&queue->lock);
+ if (!RPC_IS_QUEUED(task)) {
+ spin_unlock_bh(&queue->lock);
continue;
}
+ rpc_clear_running(task);
+ spin_unlock_bh(&queue->lock);
+ if (task_is_async)
+ return;
/* sync task: sleep here */
dprintk("RPC: %5u sync task going to sleep\n", task->tk_pid);
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