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References: <20221021204126.927603-1-rafaelmendsr@gmail.com>
In-Reply-To: <20221021204126.927603-1-rafaelmendsr@gmail.com>
From:   Suwan Kim <suwan.kim027@gmail.com>
Date:   Mon, 24 Oct 2022 23:46:42 +0900
Message-ID: <CAFNWusaY7NyW1zEAki0mEGzuCPpOONXfo2bHPCdDG=5ktgAFuw@mail.gmail.com>
Subject: Re: [PATCH] virtio_blk: Fix signedness bug in virtblk_prep_rq()
To:     Rafael Mendonca <rafaelmendsr@gmail.com>
Cc:     "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Stefan Hajnoczi <stefanha@redhat.com>,
        Jens Axboe <axboe@kernel.dk>,
        Chaitanya Kulkarni <kch@nvidia.com>,
        virtualization@lists.linux-foundation.org,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
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Precedence: bulk

On Sat, Oct 22, 2022 at 5:42 AM Rafael Mendonca <rafaelmendsr@gmail.com> wrote:
>
> The virtblk_map_data() function returns negative error codes, however, the
> 'nents' field of vbr->sg_table is an unsigned int, which causes the error
> handling not to work correctly.
>
> Fixes: 0e9911fa768f ("virtio-blk: support mq_ops->queue_rqs()")
> Signed-off-by: Rafael Mendonca <rafaelmendsr@gmail.com>
> ---
>  drivers/block/virtio_blk.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 19da5defd734..291f705e61a8 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -321,16 +321,18 @@ static blk_status_t virtblk_prep_rq(struct blk_mq_hw_ctx *hctx,
>                                         struct virtblk_req *vbr)
>  {
>         blk_status_t status;
> +       int num;
>
>         status = virtblk_setup_cmd(vblk->vdev, req, vbr);
>         if (unlikely(status))
>                 return status;
>
> -       vbr->sg_table.nents = virtblk_map_data(hctx, req, vbr);
> -       if (unlikely(vbr->sg_table.nents < 0)) {
> +       num = virtblk_map_data(hctx, req, vbr);
> +       if (unlikely(num < 0)) {
>                 virtblk_cleanup_cmd(req);
>                 return BLK_STS_RESOURCE;
>         }
> +       vbr->sg_table.nents = num;
>
>         blk_mq_start_request(req);
>
> --
> 2.34.1
>

Looks good to me!

Reviewed-by: Suwan Kim <suwan.kim027@gmail.com>