Commit 114eccdf authored by Dylan Yudaken's avatar Dylan Yudaken Committed by Jens Axboe
Browse files

io_uring: add IOU_STOP_MULTISHOT return code 



For multishot we want a way to signal the caller that multishot has ended
but also this might not be an error return.

For example sockets return 0 when closed, which should end a multishot
recv, but still have a CQE with result 0

Introduce IOU_STOP_MULTISHOT which does this and indicates that the return
code is stored inside req->cqe

Signed-off-by: default avatarDylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220630091231.1456789-7-dylany@fb.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 2ba69707

io_uring/io_uring.h

+7 −0
Original line number Diff line number Diff line
@@ -15,6 +15,13 @@ 
enum {

	IOU_OK			= 0,

	IOU_ISSUE_SKIP_COMPLETE	= -EIOCBQUEUED,



	/*

	 * Intended only when both REQ_F_POLLED and REQ_F_APOLL_MULTISHOT

	 * are set to indicate to the poll runner that multishot should be

	 * removed and the result is set on req->cqe.res.

	 */

	IOU_STOP_MULTISHOT	= -ECANCELED,

};



struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx);

io_uring/poll.c

+9 −2
Original line number Diff line number Diff line
@@ -195,6 +195,7 @@ static void io_poll_remove_entries(struct io_kiocb *req) 
enum {

	IOU_POLL_DONE = 0,

	IOU_POLL_NO_ACTION = 1,

	IOU_POLL_REMOVE_POLL_USE_RES = 2,

};



/*
@@ -204,6 +205,8 @@ enum { 
 * Returns a negative error on failure. IOU_POLL_NO_ACTION when no action require,

 * which is either spurious wakeup or multishot CQE is served.

 * IOU_POLL_DONE when it's done with the request, then the mask is stored in req->cqe.res.

 * IOU_POLL_REMOVE_POLL_USE_RES indicates to remove multishot poll and that the result

 * is stored in req->cqe.

 */

static int io_poll_check_events(struct io_kiocb *req, bool *locked)

{
@@ -244,6 +247,8 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked) 
				return -ECANCELED;

		} else {

			ret = io_poll_issue(req, locked);

			if (ret == IOU_STOP_MULTISHOT)

				return IOU_POLL_REMOVE_POLL_USE_RES;

			if (ret < 0)

				return ret;

		}
@@ -268,7 +273,7 @@ static void io_poll_task_func(struct io_kiocb *req, bool *locked) 
	if (ret == IOU_POLL_DONE) {

		struct io_poll *poll = io_kiocb_to_cmd(req);

		req->cqe.res = mangle_poll(req->cqe.res & poll->events);

	} else {

	} else if (ret != IOU_POLL_REMOVE_POLL_USE_RES) {

		req->cqe.res = ret;

		req_set_fail(req);

	}
@@ -291,7 +296,9 @@ static void io_apoll_task_func(struct io_kiocb *req, bool *locked) 
	io_poll_remove_entries(req);

	io_poll_tw_hash_eject(req, locked);



	if (!ret)

	if (ret == IOU_POLL_REMOVE_POLL_USE_RES)

		io_req_complete_post(req);

	else if (ret == IOU_POLL_DONE)

		io_req_task_submit(req, locked);

	else

		io_req_complete_failed(req, ret);