Add API to check ring capacity. Because of the option
to use indirect buffers, this returns the worst
case, not the normal case capacity.
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
drivers/virtio/virtio_ring.c | 8 ++++++++
include/linux/virtio.h | 5 +++++
2 files changed, 13 insertions(+), 0 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 68b9136..23422f1 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -344,6 +344,14 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
}
EXPORT_SYMBOL_GPL(virtqueue_get_buf);
+int virtqueue_min_capacity(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ return vq->num_free;
+}
+EXPORT_SYMBOL_GPL(virtqueue_min_capacity);
+
void virtqueue_disable_cb(struct virtqueue *_vq)
{
struct vring_virtqueue *vq = to_vvq(_vq);
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 7108857..209220d 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -42,6 +42,9 @@ struct virtqueue {
* vq: the struct virtqueue we're talking about.
* len: the length written into the buffer
* Returns NULL or the "data" token handed to add_buf.
+ * virtqueue_min_capacity: get the current capacity of the queue
+ * vq: the struct virtqueue we're talking about.
+ * Returns the current worst case capacity of the queue.
* virtqueue_disable_cb: disable callbacks
* vq: the struct virtqueue we're talking about.
* Note that this is not necessarily synchronous, hence unreliable and only
@@ -89,6 +92,8 @@ void virtqueue_kick(struct virtqueue *vq);
void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
+int virtqueue_min_capacity(struct virtqueue *vq);
+
void virtqueue_disable_cb(struct virtqueue *vq);
bool virtqueue_enable_cb(struct virtqueue *vq);
--
1.7.5.53.gc233e
--
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