Commit 581f9810 authored by Bijan Mottahedeh's avatar Bijan Mottahedeh Committed by Jens Axboe
Browse files

io_uring: process requests completed with -EAGAIN on poll list 



A request that completes with an -EAGAIN result after it has been added
to the poll list, will not be removed from that list in io_do_iopoll()
because the f_op->iopoll() will not succeed for that request.

Maintain a retryable local list similar to the done list, and explicity
reissue requests with an -EAGAIN result.

Signed-off-by: default avatarBijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent c336e992

fs/io_uring.c

+26 −3
Original line number Diff line number Diff line
@@ -1744,11 +1744,24 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, 
	io_free_req_many(ctx, &rb);

}



static void io_iopoll_queue(struct list_head *again)

{

	struct io_kiocb *req;



	do {

		req = list_first_entry(again, struct io_kiocb, list);

		list_del(&req->list);

		refcount_inc(&req->refs);

		io_queue_async_work(req);

	} while (!list_empty(again));

}



static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,

			long min)

{

	struct io_kiocb *req, *tmp;

	LIST_HEAD(done);

	LIST_HEAD(again);

	bool spin;

	int ret;
@@ -1763,9 +1776,9 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events, 
		struct kiocb *kiocb = &req->rw.kiocb;



		/*

		 * Move completed entries to our local list. If we find a

		 * request that requires polling, break out and complete

		 * the done list first, if we have entries there.

		 * Move completed and retryable entries to our local lists.

		 * If we find a request that requires polling, break out

		 * and complete those lists first, if we have entries there.

		 */

		if (req->flags & REQ_F_IOPOLL_COMPLETED) {

			list_move_tail(&req->list, &done);
@@ -1774,6 +1787,13 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events, 
		if (!list_empty(&done))

			break;



		if (req->result == -EAGAIN) {

			list_move_tail(&req->list, &again);

			continue;

		}

		if (!list_empty(&again))

			break;



		ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin);

		if (ret < 0)

			break;
@@ -1786,6 +1806,9 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events, 
	if (!list_empty(&done))

		io_iopoll_complete(ctx, nr_events, &done);



	if (!list_empty(&again))

		io_iopoll_queue(&again);



	return ret;

}

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