Re: [PATCH v1 01/11] io_uring: support CQE32 in io_uring_cqe

Kanchan Joshi
2022-04-22T01:51:43Z

On Thu, Apr 21, 2022 at 12:02 PM Stefan Roesch <shr@fb.com> wrote:
>
> This adds the struct io_uring_cqe_extra in the structure io_uring_cqe to
> support large CQE's.
>
> Co-developed-by: Jens Axboe <axboe@kernel.dk>
> Signed-off-by: Stefan Roesch <shr@fb.com>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
> include/uapi/linux/io_uring.h | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
> index ee677dbd6a6d..6f9f9b6a9d15 100644
> --- a/include/uapi/linux/io_uring.h
> +++ b/include/uapi/linux/io_uring.h
> @@ -111,6 +111,7 @@ enum {
> #define IORING_SETUP_R_DISABLED (1U << 6) /* start with ring disabled */
> #define IORING_SETUP_SUBMIT_ALL (1U << 7) /* continue submit on error */
> #define IORING_SETUP_SQE128 (1U << 8) /* SQEs are 128b */
> +#define IORING_SETUP_CQE32 (1U << 9) /* CQEs are 32b */
>
> enum {
> IORING_OP_NOP,
> @@ -201,6 +202,11 @@ enum {
> #define IORING_POLL_UPDATE_EVENTS (1U << 1)
> #define IORING_POLL_UPDATE_USER_DATA (1U << 2)
>
> +struct io_uring_cqe_extra {
> + __u64 extra1;
> + __u64 extra2;
> +};
> +
> /*
> * IO completion data structure (Completion Queue Entry)
> */
> @@ -208,6 +214,12 @@ struct io_uring_cqe {
> __u64 user_data; /* sqe->data submission passed back */
> __s32 res; /* result code for this event */
> __u32 flags;
> +
> + /*
> + * If the ring is initialized with IORING_SETUP_CQE32, then this field
> + * contains 16-bytes of padding, doubling the size of the CQE.
> + */
> + struct io_uring_cqe_extra b[0];
> };
Will it be any better to replace struct b[0] with "u64 extra[ ]" ?
With that new fields will be referred as cqe->extra[0] and cqe->extra[1].

And if we go that route, maybe "aux" sounds better than "extra".