From: Gabriel Krisman Bertazi <[email protected]>
To: Pavel Begunkov <[email protected]>
Cc: [email protected], Jens Axboe <[email protected]>
Subject: Re: [PATCH 1/3] io_uring: simplify io_mem_alloc return values
Date: Wed, 13 Mar 2024 18:32:42 -0400 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <ba1f5a30be45eec6cf73cfdbf4b4e1679a03cef8.1710343154.git.asml.silence@gmail.com> (Pavel Begunkov's message of "Wed, 13 Mar 2024 15:52:39 +0000")
Pavel Begunkov <[email protected]> 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 <[email protected]>
> ---
> 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
next prev parent reply other threads:[~2024-03-13 22:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-13 15:52 [PATCH 0/3] small rings clean up Pavel Begunkov
2024-03-13 15:52 ` [PATCH 1/3] io_uring: simplify io_mem_alloc return values Pavel Begunkov
2024-03-13 20:50 ` Jens Axboe
2024-03-13 20:43 ` Pavel Begunkov
2024-03-13 21:02 ` Jens Axboe
2024-03-13 22:32 ` Gabriel Krisman Bertazi [this message]
2024-03-13 23:24 ` Jens Axboe
2024-03-13 23:43 ` Gabriel Krisman Bertazi
2024-03-13 23:44 ` Jens Axboe
2024-03-13 15:52 ` [PATCH 2/3] io_uring: simplify io_pages_free Pavel Begunkov
2024-03-13 15:52 ` [PATCH 3/3] io_uring/kbuf: rename is_mapped Pavel Begunkov
2024-03-13 20:27 ` [PATCH 0/3] small rings clean up Jens Axboe
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