On Wed, 22 Oct 2014 17:02:26 +0300
"Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:
> On Tue, Oct 07, 2014 at 04:39:45PM +0200, Cornelia Huck wrote:
> > From: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> >
> > [Cornelia Huck: we don't need the vq->vring.num -> vq->ring_mask change]
> > Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> > Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
> > ---
> > drivers/virtio/virtio_ring.c | 195 ++++++++++++++++++++++++++++++------------
> > 1 file changed, 138 insertions(+), 57 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > index 1cfb5ba..350c39b 100644
> > --- a/drivers/virtio/virtio_ring.c
> > +++ b/drivers/virtio/virtio_ring.c
> > @@ -145,42 +145,54 @@ static inline int vring_add_indirect(struct vring_virtqueue *vq,
> > i = 0;
> > for (n = 0; n < out_sgs; n++) {
> > for (sg = sgs[n]; sg; sg = next(sg, &total_out)) {
> > - desc[i].flags = VRING_DESC_F_NEXT;
> > - desc[i].addr = sg_phys(sg);
> > - desc[i].len = sg->length;
> > - desc[i].next = i+1;
> > + desc[i].flags = cpu_to_virtio16(vq->vq.vdev,
> > + VRING_DESC_F_NEXT);
> > + desc[i].addr = cpu_to_virtio64(vq->vq.vdev,
> > + sg_phys(sg));
> > + desc[i].len = cpu_to_virtio32(vq->vq.vdev,
> > + sg->length);
> > + desc[i].next = cpu_to_virtio16(vq->vq.vdev,
> > + i+1);
> > i++;
> > }
> > }
> > for (; n < (out_sgs + in_sgs); n++) {
> > for (sg = sgs[n]; sg; sg = next(sg, &total_in)) {
> > - desc[i].flags = VRING_DESC_F_NEXT|VRING_DESC_F_WRITE;
> > - desc[i].addr = sg_phys(sg);
> > - desc[i].len = sg->length;
> > - desc[i].next = i+1;
> > + desc[i].flags = cpu_to_virtio16(vq->vq.vdev,
> > + VRING_DESC_F_NEXT|
> > + VRING_DESC_F_WRITE);
> > + desc[i].addr = cpu_to_virtio64(vq->vq.vdev,
> > + sg_phys(sg));
> > + desc[i].len = cpu_to_virtio32(vq->vq.vdev,
> > + sg->length);
> > + desc[i].next = cpu_to_virtio16(vq->vq.vdev, i+1);
> > i++;
> > }
> > }
> > - BUG_ON(i != total_sg);
> >
> > /* Last one doesn't continue. */
> > - desc[i-1].flags &= ~VRING_DESC_F_NEXT;
> > + desc[i-1].flags &= ~cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);
> > desc[i-1].next = 0;
> >
> > - /* We're about to use a buffer */
> > - vq->vq.num_free--;
> > -
> > /* Use a single buffer which doesn't continue */
> > head = vq->free_head;
> > - vq->vring.desc[head].flags = VRING_DESC_F_INDIRECT;
> > - vq->vring.desc[head].addr = virt_to_phys(desc);
> > + vq->vring.desc[head].flags =
> > + cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT);
> > + vq->vring.desc[head].addr =
> > + cpu_to_virtio64(vq->vq.vdev, virt_to_phys(desc));
> > /* kmemleak gives a false positive, as it's hidden by virt_to_phys */
> > kmemleak_ignore(desc);
> > - vq->vring.desc[head].len = i * sizeof(struct vring_desc);
> > + vq->vring.desc[head].len =
> > + cpu_to_virtio32(vq->vq.vdev, i * sizeof(struct vring_desc));
> >
> > - /* Update free pointer */
> > + BUG_ON(i != total_sg);
> > +
>
> Why move the BUG_ON here?
> I think I'll move it back ...
IIRC this was in the original patch I applied - but you're right, the
statement can stay in the old place.
>
> > + /* Update free pointer (we store this in native endian) */
> > vq->free_head = vq->vring.desc[head].next;
> >
> > + /* We've just used a buffer */
> > + vq->vq.num_free--;
> > +
> > return head;
> > }
> >
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