Re: [PATCH 3/5] io_uring: make io_alloc_ocqe() take a struct io_cqe pointer

[Caleb Sander Mateos <csander@purestorage.com>]

On Fri, May 16, 2025 at 1:10 PM Jens Axboe <axboe@kernel.dk> wrote:
>
> The number of arguments to io_alloc_ocqe() is a bit unwieldy. Make it
> take a struct io_cqe pointer rather than three sepearate CQE args. One

typo: "separate"

> path already has that readily available, add an io_init_cqe() helper for
> the remainding two.

typo: "remaining"

>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
>  io_uring/io_uring.c | 24 ++++++++++++++----------
>  1 file changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
> index b564a1bdc068..b50c2d434e74 100644
> --- a/io_uring/io_uring.c
> +++ b/io_uring/io_uring.c
> @@ -724,8 +724,8 @@ static bool io_cqring_add_overflow(struct io_ring_ctx *ctx,
>  }
>
>  static struct io_overflow_cqe *io_alloc_ocqe(struct io_ring_ctx *ctx,
> -                                            u64 user_data, s32 res, u32 cflags,
> -                                            u64 extra1, u64 extra2, gfp_t gfp)
> +                                            struct io_cqe *cqe, u64 extra1,
> +                                            u64 extra2, gfp_t gfp)
>  {
>         struct io_overflow_cqe *ocqe;
>         size_t ocq_size = sizeof(struct io_overflow_cqe);
> @@ -735,11 +735,11 @@ static struct io_overflow_cqe *io_alloc_ocqe(struct io_ring_ctx *ctx,
>                 ocq_size += sizeof(struct io_uring_cqe);
>
>         ocqe = kmalloc(ocq_size, gfp | __GFP_ACCOUNT);
> -       trace_io_uring_cqe_overflow(ctx, user_data, res, cflags, ocqe);
> +       trace_io_uring_cqe_overflow(ctx, cqe->user_data, cqe->res, cqe->flags, ocqe);
>         if (ocqe) {
> -               ocqe->cqe.user_data = user_data;
> -               ocqe->cqe.res = res;
> -               ocqe->cqe.flags = cflags;
> +               ocqe->cqe.user_data = cqe->user_data;
> +               ocqe->cqe.res = cqe->res;
> +               ocqe->cqe.flags = cqe->flags;
>                 if (is_cqe32) {
>                         ocqe->cqe.big_cqe[0] = extra1;
>                         ocqe->cqe.big_cqe[1] = extra2;
> @@ -806,6 +806,9 @@ static bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res,
>         return false;
>  }
>
> +#define io_init_cqe(user_data, res, cflags)    \
> +       (struct io_cqe) { .user_data = user_data, .res = res, .flags = cflags }

The arguments and result should be parenthesized to prevent unexpected
groupings. Better yet, make this a static inline function.

> +
>  bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags)
>  {
>         bool filled;
> @@ -814,8 +817,9 @@ bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags
>         filled = io_fill_cqe_aux(ctx, user_data, res, cflags);
>         if (unlikely(!filled)) {
>                 struct io_overflow_cqe *ocqe;
> +               struct io_cqe cqe = io_init_cqe(user_data, res, cflags);
>
> -               ocqe = io_alloc_ocqe(ctx, user_data, res, cflags, 0, 0, GFP_ATOMIC);
> +               ocqe = io_alloc_ocqe(ctx, &cqe, 0, 0, GFP_ATOMIC);
>                 filled = io_cqring_add_overflow(ctx, ocqe);
>         }
>         io_cq_unlock_post(ctx);
> @@ -833,8 +837,9 @@ void io_add_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags)
>
>         if (!io_fill_cqe_aux(ctx, user_data, res, cflags)) {
>                 struct io_overflow_cqe *ocqe;
> +               struct io_cqe cqe = io_init_cqe(user_data, res, cflags);
>
> -               ocqe = io_alloc_ocqe(ctx, user_data, res, cflags, 0, 0, GFP_KERNEL);
> +               ocqe = io_alloc_ocqe(ctx, &cqe, 0, 0, GFP_KERNEL);
>                 spin_lock(&ctx->completion_lock);
>                 io_cqring_add_overflow(ctx, ocqe);
>                 spin_unlock(&ctx->completion_lock);
> @@ -1444,8 +1449,7 @@ void __io_submit_flush_completions(struct io_ring_ctx *ctx)
>                         gfp_t gfp = ctx->lockless_cq ? GFP_KERNEL : GFP_ATOMIC;
>                         struct io_overflow_cqe *ocqe;
>
> -                       ocqe = io_alloc_ocqe(ctx, req->cqe.user_data, req->cqe.res,
> -                                            req->cqe.flags, req->big_cqe.extra1,
> +                       ocqe = io_alloc_ocqe(ctx, &req->cqe, req->big_cqe.extra1,
>                                              req->big_cqe.extra2, gfp);

If the req->big_cqe type were named, these 2 arguments could be
combined into just &req->big_cqe.

Best,
Caleb

>                         if (ctx->lockless_cq) {
>                                 spin_lock(&ctx->completion_lock);
> --
> 2.49.0
>