On 08/04/2021 01:54, Pavel Begunkov wrote:
> poll->canceled may be set from different contexts, even async, so
> io_poll_rewait() should be prepared that it can change and not read it
> twice.
Please disregard this one, apparently it's not a bug and will get in
my way letter. Other 3 are fine.
>
> Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
> ---
> 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 de5822350345..376d9c875dc2 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -4897,15 +4897,16 @@ static bool io_poll_rewait(struct io_kiocb *req, struct io_poll_iocb *poll)
> __acquires(&req->ctx->completion_lock)
> {
> struct io_ring_ctx *ctx = req->ctx;
> + bool canceled = READ_ONCE(poll->canceled);
>
> - if (!req->result && !READ_ONCE(poll->canceled)) {
> + if (!req->result && !canceled) {
> struct poll_table_struct pt = { ._key = poll->events };
>
> req->result = vfs_poll(req->file, &pt) & poll->events;
> }
>
> spin_lock_irq(&ctx->completion_lock);
> - if (!req->result && !READ_ONCE(poll->canceled)) {
> + if (!req->result && !canceled) {
> add_wait_queue(poll->head, &poll->wait);
> return true;
> }
>
--
Pavel Begunkov
