[PATCH] io_uring: async task poll trigger cleanup

[PATCH] io_uring: async task poll trigger cleanup

[Jens Axboe]

If the request is still hashed in io_async_task_func(), then it cannot
have been canceled and it's pointless to check. So save that check.
Likewise, for the poll state, if we're freeing apoll, don't bother
marking it as done.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/io_uring.c | 34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1317a4478994..4c73ed76cac7 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4354,7 +4354,7 @@ static void io_async_task_func(struct callback_head *cb)
 	struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
 	struct async_poll *apoll = req->apoll;
 	struct io_ring_ctx *ctx = req->ctx;
-	bool canceled;
+	bool canceled = false;
 
 	trace_io_uring_task_run(req->ctx, req->opcode, req->user_data);
 
@@ -4363,34 +4363,33 @@ static void io_async_task_func(struct callback_head *cb)
 		return;
 	}
 
-	if (hash_hashed(&req->hash_node))
+	/* If req is still hashed, it cannot have been canceled. Don't check. */
+	if (hash_hashed(&req->hash_node)) {
 		hash_del(&req->hash_node);
-
-	canceled = READ_ONCE(apoll->poll.canceled);
-	if (canceled) {
-		io_cqring_fill_event(req, -ECANCELED);
-		io_commit_cqring(ctx);
+	} else {
+		canceled = READ_ONCE(apoll->poll.canceled);
+		if (canceled) {
+			io_cqring_fill_event(req, -ECANCELED);
+			io_commit_cqring(ctx);
+		}
 	}
 
 	spin_unlock_irq(&ctx->completion_lock);
 
 	/* restore ->work in case we need to retry again */
 	memcpy(&req->work, &apoll->work, sizeof(req->work));
+	kfree(apoll);
 
-	if (canceled) {
-		kfree(apoll);
+	if (!canceled) {
+		__set_current_state(TASK_RUNNING);
+		mutex_lock(&ctx->uring_lock);
+		__io_queue_sqe(req, NULL);
+		mutex_unlock(&ctx->uring_lock);
+	} else {
 		io_cqring_ev_posted(ctx);
 		req_set_fail_links(req);
 		io_double_put_req(req);
-		return;
 	}
-
-	__set_current_state(TASK_RUNNING);
-	mutex_lock(&ctx->uring_lock);
-	__io_queue_sqe(req, NULL);
-	mutex_unlock(&ctx->uring_lock);
-
-	kfree(apoll);
 }
 
 static int io_async_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
@@ -4496,7 +4495,6 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
 					io_async_wake);
 	if (ret) {
 		ipt.error = 0;
-		apoll->poll.done = true;
 		/* only remove double add if we did it here */
 		if (!had_io)
 			io_poll_remove_double(req);
-- 
2.26.2

-- 
Jens Axboe