Michael S. Tsirkin
2022-May-27 10:24 UTC
[PATCH] virtio_balloon: check virtqueue_add_outbuf() return value
On Thu, May 26, 2022 at 09:34:01PM -0400, Bo Liu wrote:> virtqueue_add_outbuf() can fail, when it fails, there is no need > to call the funciont virtqueue_kick(). > Signed-off-by: Bo Liu <liubo03 at inspur.com>Sorry don't get it. What's the point of this patch really?> --- > drivers/virtio/virtio_balloon.c | 18 +++++++++++------- > 1 file changed, 11 insertions(+), 7 deletions(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index b9737da6c4dd..0d7da4d95e1e 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -153,16 +153,18 @@ static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq) > { > struct scatterlist sg; > unsigned int len; > + int err; > > sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns); > > /* We should always be able to add one buffer to an empty queue. */ > - virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); > - virtqueue_kick(vq); > - > - /* When host has read buffer, this completes via balloon_ack */ > - wait_event(vb->acked, virtqueue_get_buf(vq, &len)); > + err = virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); > + if (!err) { > + virtqueue_kick(vq); > > + /* When host has read buffer, this completes via balloon_ack */ > + wait_event(vb->acked, virtqueue_get_buf(vq, &len)); > + } > } > > static int virtballoon_free_page_report(struct page_reporting_dev_info *pr_dev_info, > @@ -382,6 +384,7 @@ static void stats_handle_request(struct virtio_balloon *vb) > struct virtqueue *vq; > struct scatterlist sg; > unsigned int len, num_stats; > + int err; > > num_stats = update_balloon_stats(vb); > > @@ -389,8 +392,9 @@ static void stats_handle_request(struct virtio_balloon *vb) > if (!virtqueue_get_buf(vq, &len)) > return; > sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats); > - virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); > - virtqueue_kick(vq); > + err = virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); > + if (!err) > + virtqueue_kick(vq); > } > > static inline s64 towards_target(struct virtio_balloon *vb) > -- > 2.27.0