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

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Message-ID: <1697794601.5857713-2-xuanzhuo@linux.alibaba.com>
Date:   Fri, 20 Oct 2023 17:36:41 +0800
From:   Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>
Cc:     jasowang@...hat.com, virtualization@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Su Hui <suhui@...china.com>
Subject: Re: [PATCH] virtio_ring: add an error code check in virtqueue_resize

On Fri, 20 Oct 2023 05:34:32 -0400, "Michael S. Tsirkin" <mst@...hat.com> wrote:
> 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;
>

How about WARN and vq->broken?

Thanks.


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