2020-05-30 11:23:03

by Pavel Begunkov

Subject: [PATCH v2] io_uring: fix overflowed reqs cancellation

Overflowed requests in io_uring_cancel_files() should be shed only of
inflight and overflowed refs. All other left references are owned by
someone else.

If refcount_sub_and_test() fails, it will go further and put put extra
ref, don't do that. Also, don't need to do io_wq_cancel_work()
for overflowed reqs, they will be let go shortly anyway.

Signed-off-by: Pavel Begunkov <[email protected]>
---

v2: don't schedule() if requests is already freed

fs/io_uring.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index bc5117ee6ce3..b1c30284efbf 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7447,10 +7447,11 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx,
finish_wait(&ctx->inflight_wait, &wait);
continue;
}
+ } else {
+ io_wq_cancel_work(ctx->io_wq, &cancel_req->work);
+ io_put_req(cancel_req);
}

- io_wq_cancel_work(ctx->io_wq, &cancel_req->work);
- io_put_req(cancel_req);
schedule();
finish_wait(&ctx->inflight_wait, &wait);
}
--
2.24.0

2020-05-30 13:52:53

by Jens Axboe

Subject: Re: [PATCH v2] io_uring: fix overflowed reqs cancellation

On 5/30/20 5:19 AM, Pavel Begunkov wrote:
> Overflowed requests in io_uring_cancel_files() should be shed only of
> inflight and overflowed refs. All other left references are owned by
> someone else.
>
> If refcount_sub_and_test() fails, it will go further and put put extra
> ref, don't do that. Also, don't need to do io_wq_cancel_work()
> for overflowed reqs, they will be let go shortly anyway.

Applied, thanks.

--
Jens Axboe