virtio: modify vring_init and vring_size to take account of the layout containing *_event_idx
Based on the layout description in the comments, take account of
the *_event_idx in functions vring_init and vring_size.
Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
index 4a32cb6..36be0f6 100644
--- a/include/linux/virtio_ring.h
+++ b/include/linux/virtio_ring.h
@@ -135,13 +135,13 @@
vr->num = num;
vr->desc = p;
vr->avail = p + num*sizeof(struct vring_desc);
- vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + align-1)
- & ~(align - 1));
+ vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + sizeof(__u16)
+ + align-1) & ~(align - 1));
}
static inline unsigned vring_size(unsigned int num, unsigned long align)
{
- return ((sizeof(struct vring_desc) * num + sizeof(__u16) * (2 + num)
+ return ((sizeof(struct vring_desc) * num + sizeof(__u16) * (3 + num)
+ align - 1) & ~(align - 1))
+ sizeof(__u16) * 3 + sizeof(struct vring_used_elem) * num;
}