Pavel Begunkov <asml.silence@xxxxxxxxx> writes:
> io_mem_alloc() returns a pointer on success and a pointer-encoded error
> otherwise. However, it can only fail with -ENOMEM, just return NULL on
> failure. PTR_ERR is usually pretty error prone.
>
> Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
> ---
> io_uring/io_uring.c | 14 +++++---------
> io_uring/kbuf.c | 4 ++--
> 2 files changed, 7 insertions(+), 11 deletions(-)
>
> diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
> index e7d7a456b489..1d0eac0cc8aa 100644
> --- a/io_uring/io_uring.c
> +++ b/io_uring/io_uring.c
> @@ -2802,12 +2802,8 @@ static void io_rings_free(struct io_ring_ctx *ctx)
> void *io_mem_alloc(size_t size)
> {
> gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP;
> - void *ret;
>
> - ret = (void *) __get_free_pages(gfp, get_order(size));
> - if (ret)
> - return ret;
> - return ERR_PTR(-ENOMEM);
> + return (void *) __get_free_pages(gfp, get_order(size));
> }
>
> static unsigned long rings_size(struct io_ring_ctx *ctx, unsigned int sq_entries,
> @@ -3762,8 +3758,8 @@ static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
> else
> rings = io_rings_map(ctx, p->cq_off.user_addr, size);
>
> - if (IS_ERR(rings))
> - return PTR_ERR(rings);
> + if (!rings)
> + return -ENOMEM;
>
Sorry, I started reviewing this, got excited about the error path quick
fix, and didn't finish the review before it got it.
I think this change is broken for the ctx->flags & IORING_SETUP_NO_MMAP
case, because io_rings_map returns ERR_PTR, and not NULL. In addition,
io_rings_map might fail for multiple reasons, and we want to propagate
the different error codes up here.
--
Gabriel Krisman Bertazi
