virtio: introduce virtqueue_unmap_sg()

Factor out sg unmapping logic. This will be reused by the patch that
can discard descriptor.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Andrew James <andrew.james@hpe.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jason Wang 2015-09-25 13:21:28 +08:00 committed by Michael S. Tsirkin
parent fa500928ad
commit ce31746157

View File

@ -244,14 +244,12 @@ int virtio_queue_empty(VirtQueue *vq)
return vring_avail_idx(vq) == vq->last_avail_idx;
}
void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
unsigned int len, unsigned int idx)
static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem,
unsigned int len)
{
unsigned int offset;
int i;
trace_virtqueue_fill(vq, elem, len, idx);
offset = 0;
for (i = 0; i < elem->in_num; i++) {
size_t size = MIN(len - offset, elem->in_sg[i].iov_len);
@ -267,6 +265,14 @@ void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
cpu_physical_memory_unmap(elem->out_sg[i].iov_base,
elem->out_sg[i].iov_len,
0, elem->out_sg[i].iov_len);
}
void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
unsigned int len, unsigned int idx)
{
trace_virtqueue_fill(vq, elem, len, idx);
virtqueue_unmap_sg(vq, elem, len);
idx = (idx + vring_used_idx(vq)) % vq->vring.num;