Commit e0eb71dc authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: don't return from io_drain_req() 



Never return from io_drain_req() but punt to tw if we've got there but
it's a false positive and we shouldn't actually drain.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/93583cee51b8783706b76c73196c155b28d9e762.1633107393.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 22b2ca31

fs/io_uring.c

+14 −22
Original line number Diff line number Diff line
@@ -6428,46 +6428,39 @@ static u32 io_get_sequence(struct io_kiocb *req) 
	return seq;

}



static bool io_drain_req(struct io_kiocb *req)

static void io_drain_req(struct io_kiocb *req)

{

	struct io_ring_ctx *ctx = req->ctx;

	struct io_defer_entry *de;

	int ret;

	u32 seq;

	u32 seq = io_get_sequence(req);



	/* Still need defer if there is pending req in defer list. */

	if (likely(list_empty_careful(&ctx->defer_list) &&

		!(req->flags & REQ_F_IO_DRAIN))) {

		ctx->drain_active = false;

		return false;

	}



	seq = io_get_sequence(req);

	/* Still a chance to pass the sequence check */

	if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list)) {

queue:

		ctx->drain_active = false;

		return false;

		io_req_task_queue(req);

		return;

	}



	ret = io_req_prep_async(req);

	if (ret)

		goto fail;

	if (ret) {

fail:

		io_req_complete_failed(req, ret);

		return;

	}

	io_prep_async_link(req);

	de = kmalloc(sizeof(*de), GFP_KERNEL);

	if (!de) {

		ret = -ENOMEM;

fail:

		io_req_complete_failed(req, ret);

		return true;

		goto fail;

	}



	spin_lock(&ctx->completion_lock);

	if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {

		spin_unlock(&ctx->completion_lock);

		kfree(de);

		io_queue_async_work(req, NULL);

		ctx->drain_active = false;

		return true;

		goto queue;

	}



	trace_io_uring_defer(ctx, req, req->user_data);
@@ -6475,7 +6468,6 @@ static bool io_drain_req(struct io_kiocb *req) 
	de->seq = seq;

	list_add_tail(&de->list, &ctx->defer_list);

	spin_unlock(&ctx->completion_lock);

	return true;

}



static void io_clean_op(struct io_kiocb *req)
@@ -6931,8 +6923,8 @@ static void io_queue_sqe_fallback(struct io_kiocb *req) 
{

	if (req->flags & REQ_F_FAIL) {

		io_req_complete_fail_submit(req);

	} else if (unlikely(req->ctx->drain_active) && io_drain_req(req)) {

		return;

	} else if (unlikely(req->ctx->drain_active)) {

		io_drain_req(req);

	} else {

		int ret = io_req_prep_async(req);