Michael S. Tsirkin
2022-Dec-26 23:36 UTC
[PATCH 2/4] virtio_ring: switch to use BAD_RING()
On Mon, Dec 26, 2022 at 03:49:06PM +0800, Jason Wang wrote:> Switch to reuse BAD_RING() to allow common logic to be implemented in > BAD_RING(). > > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > Changes since V1: > - switch to use BAD_RING in virtio_break_device() > --- > drivers/virtio/virtio_ring.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 2e7689bb933b..5cfb2fa8abee 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -58,7 +58,8 @@ > do { \ > dev_err(&_vq->vq.vdev->dev, \ > "%s:"fmt, (_vq)->vq.name, ##args); \ > - (_vq)->broken = true; \ > + /* Pairs with READ_ONCE() in virtqueue_is_broken(). */ \I don't think WRITE_ONCE/READ_ONCE pair as such. Can you point me at documentation of such pairing?> + WRITE_ONCE((_vq)->broken, true); \ > } while (0) > #define START_USE(vq) > #define END_USE(vq) > @@ -2237,7 +2238,7 @@ bool virtqueue_notify(struct virtqueue *_vq) > > /* Prod other side to tell it about changes. */ > if (!vq->notify(_vq)) { > - vq->broken = true; > + BAD_RING(vq, "vq %d is broken\n", vq->vq.index); > return false; > } > return true; > @@ -2786,8 +2787,7 @@ void virtio_break_device(struct virtio_device *dev) > list_for_each_entry(_vq, &dev->vqs, list) { > struct vring_virtqueue *vq = to_vvq(_vq); > > - /* Pairs with READ_ONCE() in virtqueue_is_broken(). */ > - WRITE_ONCE(vq->broken, true); > + BAD_RING(vq, "Device break vq %d", _vq->index); > } > spin_unlock(&dev->vqs_list_lock); > } > -- > 2.25.1
On Tue, Dec 27, 2022 at 7:36 AM Michael S. Tsirkin <mst at redhat.com> wrote:> > On Mon, Dec 26, 2022 at 03:49:06PM +0800, Jason Wang wrote: > > Switch to reuse BAD_RING() to allow common logic to be implemented in > > BAD_RING(). > > > > Signed-off-by: Jason Wang <jasowang at redhat.com> > > --- > > Changes since V1: > > - switch to use BAD_RING in virtio_break_device() > > --- > > drivers/virtio/virtio_ring.c | 8 ++++---- > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > > index 2e7689bb933b..5cfb2fa8abee 100644 > > --- a/drivers/virtio/virtio_ring.c > > +++ b/drivers/virtio/virtio_ring.c > > @@ -58,7 +58,8 @@ > > do { \ > > dev_err(&_vq->vq.vdev->dev, \ > > "%s:"fmt, (_vq)->vq.name, ##args); \ > > - (_vq)->broken = true; \ > > + /* Pairs with READ_ONCE() in virtqueue_is_broken(). */ \ > > I don't think WRITE_ONCE/READ_ONCE pair as such. Can you point > me at documentation of such pairing?Introduced by: commit 60f0779862e4ab943810187752c462e85f5fa371 Author: Parav Pandit <parav at nvidia.com> Date: Wed Jul 21 17:26:45 2021 +0300 virtio: Improve vq->broken access to avoid any compiler optimization I think it might still apply here since virtqueue_is_broken() is still put into a loop inside wait_event(). Thanks> > > + WRITE_ONCE((_vq)->broken, true); \ > > } while (0) > > #define START_USE(vq) > > #define END_USE(vq) > > @@ -2237,7 +2238,7 @@ bool virtqueue_notify(struct virtqueue *_vq) > > > > /* Prod other side to tell it about changes. */ > > if (!vq->notify(_vq)) { > > - vq->broken = true; > > + BAD_RING(vq, "vq %d is broken\n", vq->vq.index); > > return false; > > } > > return true; > > @@ -2786,8 +2787,7 @@ void virtio_break_device(struct virtio_device *dev) > > list_for_each_entry(_vq, &dev->vqs, list) { > > struct vring_virtqueue *vq = to_vvq(_vq); > > > > - /* Pairs with READ_ONCE() in virtqueue_is_broken(). */ > > - WRITE_ONCE(vq->broken, true); > > + BAD_RING(vq, "Device break vq %d", _vq->index); > > } > > spin_unlock(&dev->vqs_list_lock); > > } > > -- > > 2.25.1 >