diff options
| author | Tiwei Bie <tiwei.bie@intel.com> | 2018-11-21 11:03:23 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-11-27 07:17:39 +0100 |
| commit | 2f18c2d153fb6fc889665688f266c780353002ec (patch) | |
| tree | 0dd9867be76f47db8de3eb1a9f5005988a36a812 /drivers/virtio | |
| parent | virtio_ring: introduce debug helpers (diff) | |
| download | linux-2f18c2d153fb6fc889665688f266c780353002ec.tar.xz linux-2f18c2d153fb6fc889665688f266c780353002ec.zip | |
virtio_ring: introduce helper for indirect feature
Introduce a helper to check whether we will use indirect
feature. It will be used by packed ring too.
Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/virtio')
| -rw-r--r-- | drivers/virtio/virtio_ring.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 10d407910aa2..d1076f28c7e9 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -145,6 +145,18 @@ struct vring_virtqueue { #define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq) +static inline bool virtqueue_use_indirect(struct virtqueue *_vq, + unsigned int total_sg) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + + /* + * If the host supports indirect descriptor tables, and we have multiple + * buffers, then go indirect. FIXME: tune this threshold + */ + return (vq->indirect && total_sg > 1 && vq->vq.num_free); +} + /* * Modern virtio devices have feature bits to specify whether they need a * quirk and bypass the IOMMU. If not there, just use the DMA API. @@ -324,9 +336,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, head = vq->free_head; - /* If the host supports indirect descriptor tables, and we have multiple - * buffers, then go indirect. FIXME: tune this threshold */ - if (vq->indirect && total_sg > 1 && vq->vq.num_free) + if (virtqueue_use_indirect(_vq, total_sg)) desc = alloc_indirect_split(_vq, total_sg, gfp); else { desc = NULL; |