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

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Message-ID: <1698040004.5365264-4-xuanzhuo@linux.alibaba.com>
Date:   Mon, 23 Oct 2023 13:46:44 +0800
From:   Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
To:     Su Hui <suhui@...china.com>
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org,
        "Michael S. Tsirkin" <mst@...hat.com>
Subject: Re: [PATCH] virtio_ring: add an error code check in virtqueue_resize

On Mon, 23 Oct 2023 11:06:48 +0800, Su Hui <suhui@...china.com> wrote:
>
> On 2023/10/23 10:53, Xuan Zhuo wrote:
> > On Mon, 23 Oct 2023 10:51:59 +0800, Su Hui <suhui@...china.com> wrote:
> >> On 2023/10/23 10:26, Xuan Zhuo wrote:
> >>>>>> Well, what are the cases where it can happen practically?
> >>>>> Device error. Such as vp_active_vq()
> >>>>>
> >>>>> Thanks.
> >>>> Hmm interesting. OK. But do callers know to recover?
> >>> No.
> >>>
> >>> So I think WARN + broken is suitable.
> >>>
> >>> Thanks.
> >> Sorry for the late, is the following code okay?
> >>
> >> @@ -2739,7 +2739,7 @@ int virtqueue_resize(struct virtqueue *_vq, u32 num,
> >>                        void (*recycle)(struct virtqueue *vq, void *buf))
> >>    {
> >>           struct vring_virtqueue *vq = to_vvq(_vq);
> >> -       int err;
> >> +       int err, err_reset;
> >>
> >>           if (num > vq->vq.num_max)
> >>                   return -E2BIG;
> >> @@ -2759,7 +2759,15 @@ int virtqueue_resize(struct virtqueue *_vq, u32 num,
> >>           else
> >>                   err = virtqueue_resize_split(_vq, num);
> >>
> >> -       return virtqueue_enable_after_reset(_vq);
> >> +       err_reset = virtqueue_enable_after_reset(_vq);
> >> +
> >> +       if (err) {
> > No err.
> >
> > err is not important.
> > You can remove that.
>
> Emm, I'm a little confused that which code should I remove ?


like this:
	if (vq->packed_ring)
		virtqueue_resize_packed(_vq, num);
	else
		virtqueue_resize_split(_vq, num);

And we should set broken and warn inside virtqueue_enable_after_reset()?

Thanks.




>
> > Thanks.
> >
> >
> >> +               vq->broken = true;
> >> +               WARN_ON(err_reset);
> >> +               return err;
> >> +       }
> >> +
> >> +       return err_reset;
> >>    }
> >>
> >> Thanks.
> >> Su Hui
> >>