io_uring: ease timeout flush locking requirements

We don't need completion_lock for timeout flushing, don't take it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1e3dc657975ac445b80e7bdc40050db783a5935a.1670002973.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/io_uring.c

@@ -572,11 +572,10 @@ static void io_eventfd_flush_signal(struct io_ring_ctx *ctx)
 
 void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
 {
-	if (ctx->off_timeout_used || ctx->drain_active) {
-		spin_lock(&ctx->completion_lock);
 	if (ctx->off_timeout_used)
 		io_flush_timeouts(ctx);
-		if (ctx->drain_active)
+	if (ctx->drain_active) {
+		spin_lock(&ctx->completion_lock);
 		io_queue_deferred(ctx);
 		spin_unlock(&ctx->completion_lock);
 	}

io_uring/timeout.c

@@ -50,7 +50,6 @@ static inline void io_put_req(struct io_kiocb *req)
 }
 
 static bool io_kill_timeout(struct io_kiocb *req, int status)
-	__must_hold(&req->ctx->completion_lock)
 	__must_hold(&req->ctx->timeout_lock)
 {
 	struct io_timeout_data *io = req->async_data;
@@ -70,7 +69,6 @@ static bool io_kill_timeout(struct io_kiocb *req, int status)
 }
 
 __cold void io_flush_timeouts(struct io_ring_ctx *ctx)
-	__must_hold(&ctx->completion_lock)
 {
 	u32 seq;
 	struct io_timeout *timeout, *tmp;