[PATCH 5.15 13/73] io_uring: refactor poll update

Greg Kroah-Hartman
2022-09-02T13:52:05Z

From: Pavel Begunkov <asml.silence@gmail.com>

[ upstream commmit 2bbb146d96f4b45e17d6aeede300796bc1a96d68 ]

Clean up io_poll_update() and unify cancellation paths for remove and
update.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5937138b6265a1285220e2fab1b28132c1d73ce3.1639605189.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[pavel: backport]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/io_uring.c | 62 ++++++++++++++++++++++++----------------------------------
1 file changed, 26 insertions(+), 36 deletions(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5931,61 +5931,51 @@ static int io_poll_update(struct io_kioc
struct io_ring_ctx *ctx = req->ctx;
struct io_kiocb *preq;
bool completing;
- int ret;
+ int ret2, ret = 0;

spin_lock(&ctx->completion_lock);
preq = io_poll_find(ctx, req->poll_update.old_user_data, true);
if (!preq) {
ret = -ENOENT;
- goto err;
- }
-
- if (!req->poll_update.update_events && !req->poll_update.update_user_data) {
- completing = true;
- ret = io_poll_remove_one(preq) ? 0 : -EALREADY;
- goto err;
+fail:
+ spin_unlock(&ctx->completion_lock);
+ goto out;
}
-
+ io_poll_remove_double(preq);
/*
* Don't allow racy completion with singleshot, as we cannot safely
* update those. For multishot, if we're racing with completion, just
* let completion re-add it.
*/
- io_poll_remove_double(preq);
completing = !__io_poll_remove_one(preq, &preq->poll, false);
if (completing && (preq->poll.events & EPOLLONESHOT)) {
ret = -EALREADY;
- goto err;
- }
- /* we now have a detached poll request. reissue. */
- ret = 0;
-err:
- if (ret < 0) {
- spin_unlock(&ctx->completion_lock);
- req_set_fail(req);
- io_req_complete(req, ret);
- return 0;
- }
- /* only mask one event flags, keep behavior flags */
- if (req->poll_update.update_events) {
- preq->poll.events &= ~0xffff;
- preq->poll.events |= req->poll_update.events & 0xffff;
- preq->poll.events |= IO_POLL_UNMASK;
+ goto fail;
}
- if (req->poll_update.update_user_data)
- preq->user_data = req->poll_update.new_user_data;
spin_unlock(&ctx->completion_lock);

+ if (req->poll_update.update_events || req->poll_update.update_user_data) {
+ /* only mask one event flags, keep behavior flags */
+ if (req->poll_update.update_events) {
+ preq->poll.events &= ~0xffff;
+ preq->poll.events |= req->poll_update.events & 0xffff;
+ preq->poll.events |= IO_POLL_UNMASK;
+ }
+ if (req->poll_update.update_user_data)
+ preq->user_data = req->poll_update.new_user_data;
+
+ ret2 = io_poll_add(preq, issue_flags);
+ /* successfully updated, don't complete poll request */
+ if (!ret2)
+ goto out;
+ }
+ req_set_fail(preq);
+ io_req_complete(preq, -ECANCELED);
+out:
+ if (ret < 0)
+ req_set_fail(req);
/* complete update request, we're done with it */
io_req_complete(req, ret);
-
- if (!completing) {
- ret = io_poll_add(preq, issue_flags);
- if (ret < 0) {
- req_set_fail(preq);
- io_req_complete(preq, ret);
- }
- }
return 0;
}