virtio: Force use of power-of-two for descriptor ring sizes

[linux-2.6-omap-h63xx.git] / drivers / virtio / virtio_ring.c

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 0e1bf053d8cd623c9e8246b118deb8e3fba12a62..1dc04b6684e6a3ce03451923d09164480932eebd 100644 (file)
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -277,11 +277,17 @@ struct virtqueue *vring_new_virtqueue(unsigned int num,
        struct vring_virtqueue *vq;
        unsigned int i;
 
+       /* We assume num is a power of 2. */
+       if (num & (num - 1)) {
+               dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num);
+               return NULL;
+       }
+
        vq = kmalloc(sizeof(*vq) + sizeof(void *)*num, GFP_KERNEL);
        if (!vq)
                return NULL;
 
-       vring_init(&vq->vring, num, pages);
+       vring_init(&vq->vring, num, pages, PAGE_SIZE);
        vq->vq.callback = callback;
        vq->vq.vdev = vdev;
        vq->vq.vq_ops = &vring_vq_ops;