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io_uring: refactor poll update

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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>
This commit is contained in:
Pavel Begunkov 2021-12-15 22:08:45 +00:00 committed by Jens Axboe
parent e840b4baf3
commit 2bbb146d96
1 changed files with 26 additions and 36 deletions
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62
fs/io_uring.c
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@ -5960,61 +5960,51 @@ static int io_poll_update(struct io_kiocb *req, unsigned int issue_flags)
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;
fail:
spin_unlock(&ctx->completion_lock);
goto out;
}
if (!req->poll_update.update_events && !req->poll_update.update_user_data) {
completing = true;
ret = io_poll_remove_one(preq) ? 0 : -EALREADY;
goto err;
}
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;
goto fail;
}
/* 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;
}
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;
}