Re: [PATCH 2/4] io_uring: return error pointer from io_mem_alloc()

[Dmitry Kadashev <dkadashev@gmail.com>]

Hi Jens,

On Sat, May 13, 2023 at 9:19 PM Jens Axboe <axboe@kernel.dk> wrote:
>
> In preparation for having more than one time of ring allocator, make the
> existing one return valid/error-pointer rather than just NULL.
>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
>  io_uring/io_uring.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
> index 3695c5e6fbf0..6266a870c89f 100644
> --- a/io_uring/io_uring.c
> +++ b/io_uring/io_uring.c
> @@ -2712,8 +2712,12 @@ static void io_mem_free(void *ptr)
>  static void *io_mem_alloc(size_t size)
>  {
>         gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP;
> +       void *ret;
>
> -       return (void *) __get_free_pages(gfp, get_order(size));
> +       ret = (void *) __get_free_pages(gfp, get_order(size));
> +       if (ret)
> +               return ret;
> +       return ERR_PTR(-ENOMEM);
>  }
>
>  static unsigned long rings_size(struct io_ring_ctx *ctx, unsigned int sq_entries,
> @@ -3673,6 +3677,7 @@ static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
>  {
>         struct io_rings *rings;
>         size_t size, sq_array_offset;
> +       void *ptr;
>
>         /* make sure these are sane, as we already accounted them */
>         ctx->sq_entries = p->sq_entries;
> @@ -3683,8 +3688,8 @@ static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
>                 return -EOVERFLOW;
>
>         rings = io_mem_alloc(size);
> -       if (!rings)
> -               return -ENOMEM;
> +       if (IS_ERR(rings))
> +               return PTR_ERR(rings);
>
>         ctx->rings = rings;
>         ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
> @@ -3703,13 +3708,14 @@ static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
>                 return -EOVERFLOW;
>         }
>
> -       ctx->sq_sqes = io_mem_alloc(size);
> -       if (!ctx->sq_sqes) {
> +       ptr = io_mem_alloc(size);
> +       if (IS_ERR(ptr)) {
>                 io_mem_free(ctx->rings);
>                 ctx->rings = NULL;
> -               return -ENOMEM;
> +               return PTR_ERR(ptr);
>         }
>
> +       ctx->sq_sqes = io_mem_alloc(size);

Should be 'ptr' rather than 'io_mem_alloc(size)' here.


-- 
Dmitry Kadashev