virtio: Add improved queue allocation API
This leaves vring_new_virtqueue alone for compatbility, but it
adds two new improved APIs:
vring_create_virtqueue: Creates a virtqueue backed by automatically
allocated coherent memory. (Some day it this could be extended to
support non-coherent memory, too, if there ends up being a platform
on which it's worthwhile.)
__vring_new_virtqueue: Creates a virtqueue with a manually-specified
layout. This should allow mic_virtio to work much more cleanly.
Signed-off-by: Andy Lutomirski <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
index a156e2b..e8d3693 100644
--- a/include/linux/virtio_ring.h
+++ b/include/linux/virtio_ring.h
@@ -59,6 +59,35 @@
struct virtio_device;
struct virtqueue;
+/*
+ * Creates a virtqueue and allocates the descriptor ring. If
+ * may_reduce_num is set, then this may allocate a smaller ring than
+ * expected. The caller should query virtqueue_get_ring_size to learn
+ * the actual size of the ring.
+ */
+struct virtqueue *vring_create_virtqueue(unsigned int index,
+ unsigned int num,
+ unsigned int vring_align,
+ struct virtio_device *vdev,
+ bool weak_barriers,
+ bool may_reduce_num,
+ bool (*notify)(struct virtqueue *vq),
+ void (*callback)(struct virtqueue *vq),
+ const char *name);
+
+/* Creates a virtqueue with a custom layout. */
+struct virtqueue *__vring_new_virtqueue(unsigned int index,
+ struct vring vring,
+ struct virtio_device *vdev,
+ bool weak_barriers,
+ bool (*notify)(struct virtqueue *),
+ void (*callback)(struct virtqueue *),
+ const char *name);
+
+/*
+ * Creates a virtqueue with a standard layout but a caller-allocated
+ * ring.
+ */
struct virtqueue *vring_new_virtqueue(unsigned int index,
unsigned int num,
unsigned int vring_align,
@@ -68,7 +97,13 @@
bool (*notify)(struct virtqueue *vq),
void (*callback)(struct virtqueue *vq),
const char *name);
+
+/*
+ * Destroys a virtqueue. If created with vring_create_virtqueue, this
+ * also frees the ring.
+ */
void vring_del_virtqueue(struct virtqueue *vq);
+
/* Filter out transport-specific feature bits. */
void vring_transport_features(struct virtio_device *vdev);
