This one changes behaviour a bit. If we haven't been able to allocate
req before, it would post an completion event with -EAGAIN. Now it will
break imidiately without consuming sqe. So the user will see, that 0
sqes was submitted/consumed.
Is that ok or we need to do something about it?
On 07/11/2019 01:00, Pavel Begunkov wrote:
> Let io_submit_sqes() to allocate io_kiocb before fetching an sqe.
>
> Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
> ---
> fs/io_uring.c | 25 ++++++++++++-------------
> 1 file changed, 12 insertions(+), 13 deletions(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 6524898831e0..0289bb3cc697 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -2551,30 +2551,23 @@ static int io_queue_link_head(struct io_ring_ctx *ctx, struct io_kiocb *req,
>
> #define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK)
>
> -static void io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s,
> - struct io_submit_state *state, struct io_kiocb **link)
> +static void io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
> + struct sqe_submit *s, struct io_submit_state *state,
> + struct io_kiocb **link)
> {
> struct io_uring_sqe *sqe_copy;
> - struct io_kiocb *req;
> int ret;
>
> /* enforce forwards compatibility on users */
> if (unlikely(s->sqe->flags & ~SQE_VALID_FLAGS)) {
> ret = -EINVAL;
> - goto err;
> - }
> -
> - req = io_get_req(ctx, state);
> - if (unlikely(!req)) {
> - ret = -EAGAIN;
> - goto err;
> + goto err_req;
> }
>
> ret = io_req_set_file(ctx, s, state, req);
> if (unlikely(ret)) {
> err_req:
> io_free_req(req, NULL);
> -err:
> io_cqring_add_event(ctx, s->sqe->user_data, ret);
> return;
> }
> @@ -2710,9 +2703,15 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
>
> for (i = 0; i < nr; i++) {
> struct sqe_submit s;
> + struct io_kiocb *req;
>
> - if (!io_get_sqring(ctx, &s))
> + req = io_get_req(ctx, statep);
> + if (unlikely(!req))
> break;
> + if (!io_get_sqring(ctx, &s)) {
> + __io_free_req(req);
> + break;
> + }
>
> if (io_sqe_needs_user(s.sqe) && !*mm) {
> mm_fault = mm_fault || !mmget_not_zero(ctx->sqo_mm);
> @@ -2740,7 +2739,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
> s.in_async = async;
> s.needs_fixed_file = async;
> trace_io_uring_submit_sqe(ctx, s.sqe->user_data, true, async);
> - io_submit_sqe(ctx, &s, statep, &link);
> + io_submit_sqe(ctx, req, &s, statep, &link);
> submitted++;
>
> /*
>
--
Pavel Begunkov
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