io_uring: clear IORING_SQ_NEED_WAKEUP after executing task works

In io_sq_thread(), if there are task works to handle, current codes
will skip schedule() and go on polling sq again, but forget to clear
IORING_SQ_NEED_WAKEUP flag, fix this issue. Also add two helpers to
set and clear IORING_SQ_NEED_WAKEUP flag,
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -6344,6 +6344,21 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
 	return submitted;
 }
 
+static inline void io_ring_set_wakeup_flag(struct io_ring_ctx *ctx)
+{
+	/* Tell userspace we may need a wakeup call */
+	spin_lock_irq(&ctx->completion_lock);
+	ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
+	spin_unlock_irq(&ctx->completion_lock);
+}
+
+static inline void io_ring_clear_wakeup_flag(struct io_ring_ctx *ctx)
+{
+	spin_lock_irq(&ctx->completion_lock);
+	ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
+	spin_unlock_irq(&ctx->completion_lock);
+}
+
 static int io_sq_thread(void *data)
 {
 	struct io_ring_ctx *ctx = data;
@@ -6417,10 +6432,7 @@ static int io_sq_thread(void *data)
 				continue;
 			}
 
-			/* Tell userspace we may need a wakeup call */
-			spin_lock_irq(&ctx->completion_lock);
-			ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
-			spin_unlock_irq(&ctx->completion_lock);
+			io_ring_set_wakeup_flag(ctx);
 
 			to_submit = io_sqring_entries(ctx);
 			if (!to_submit || ret == -EBUSY) {
@@ -6430,6 +6442,7 @@ static int io_sq_thread(void *data)
 				}
 				if (io_run_task_work()) {
 					finish_wait(&ctx->sqo_wait, &wait);
+					io_ring_clear_wakeup_flag(ctx);
 					continue;
 				}
 				if (signal_pending(current))
@@ -6437,17 +6450,13 @@ static int io_sq_thread(void *data)
 				schedule();
 				finish_wait(&ctx->sqo_wait, &wait);
 
-				spin_lock_irq(&ctx->completion_lock);
-				ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
-				spin_unlock_irq(&ctx->completion_lock);
+				io_ring_clear_wakeup_flag(ctx);
 				ret = 0;
 				continue;
 			}
 			finish_wait(&ctx->sqo_wait, &wait);
 
-			spin_lock_irq(&ctx->completion_lock);
-			ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
-			spin_unlock_irq(&ctx->completion_lock);
+			io_ring_clear_wakeup_flag(ctx);
 		}
 
 		mutex_lock(&ctx->uring_lock);