linux-kernel - Re: [PATCH] virtio_ring: add an error code check in virtqueue

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Message-ID: <20231020053047-mutt-send-email-mst@kernel.org>
Date:   Fri, 20 Oct 2023 05:34:32 -0400
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     Su Hui <suhui@...china.com>
Cc:     jasowang@...hat.com, xuanzhuo@...ux.alibaba.com,
        virtualization@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] virtio_ring: add an error code check in virtqueue_resize

On Fri, Oct 20, 2023 at 05:23:21PM +0800, Su Hui wrote:
> virtqueue_resize_packed() or virtqueue_resize_split() can return
> error code if failed, so add a check for this.
> 
> Signed-off-by: Su Hui <suhui@...china.com>
> ---
> 
> I'm not sure that return directly is right or not,
> maybe there are some process should do before return.

yes - presizely what virtqueue_enable_after_reset does.

Error handling in virtqueue_enable_after_reset is really weird BTW.
For some reason it overrides the error code returned.





>  drivers/virtio/virtio_ring.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 51d8f3299c10..cf662c3a755b 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -2759,6 +2759,9 @@ int virtqueue_resize(struct virtqueue *_vq, u32 num,
>  	else
>  		err = virtqueue_resize_split(_vq, num);
>  
> +	if (err)
> +		return err;
> +
>  	return virtqueue_enable_after_reset(_vq);

So I think it should be something like:

	int err_reset = virtqueue_enable_after_reset(_vq);
	BUG_ON(err_reset);

	return err;



>  }
>  EXPORT_SYMBOL_GPL(virtqueue_resize);
> -- 
> 2.30.2