SUNRPC: Tighten up the task locking rules in __rpc_execute() (eb9b55ab) · Commits · 戴 / test

net/sunrpc/sched.c

+20 −13

Original line number	Diff line number	Diff line
		@@ -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;

		@@ -607,6 +602,8 @@ void rpc_release_calldata(const struct rpc_call_ops ops, void calldata)
		*/
		static void __rpc_execute(struct rpc_task *task)
		{
		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",
		@@ -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);