Introduce virtqueue_get_capacity() to help bail out of transmit
path early. Also remove notification when we run out of space (I
am not sure if this should be under a feature bit).
Signed-off-by: Krishna Kumar <krkum...@in.ibm.com>
---
drivers/virtio/virtio_ring.c | 13 ++++++++-----
include/linux/virtio.h | 5 +++++
2 files changed, 13 insertions(+), 5 deletions(-)
diff -ruNp org/include/linux/virtio.h new/include/linux/virtio.h
--- org/include/linux/virtio.h 2011-05-04 18:57:06.000000000 +0530
+++ new/include/linux/virtio.h 2011-05-04 18:57:09.000000000 +0530
@@ -27,6 +27,9 @@ struct virtqueue {
/**
* operations for virtqueue
+ * virtqueue_get_capacity: Get vq capacity
+ * vq: the struct virtqueue we're talking about.
+ * Returns remaining capacity of queue
* virtqueue_add_buf: expose buffer to other end
* vq: the struct virtqueue we're talking about.
* sg: the description of the buffer(s).
@@ -62,6 +65,8 @@ struct virtqueue {
* All operations can be called in any context.
*/
+int virtqueue_get_capacity(struct virtqueue *vq);
+
int virtqueue_add_buf_gfp(struct virtqueue *vq,
struct scatterlist sg[],
unsigned int out_num,
diff -ruNp org/drivers/virtio/virtio_ring.c new/drivers/virtio/virtio_ring.c
--- org/drivers/virtio/virtio_ring.c 2011-05-04 18:57:06.000000000 +0530
+++ new/drivers/virtio/virtio_ring.c 2011-05-04 18:57:09.000000000 +0530
@@ -156,6 +156,14 @@ static int vring_add_indirect(struct vri
return head;
}
+int virtqueue_get_capacity(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ return vq->num_free;
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_capacity);
+
int virtqueue_add_buf_gfp(struct virtqueue *_vq,
struct scatterlist sg[],
unsigned int out,
@@ -185,11 +193,6 @@ int virtqueue_add_buf_gfp(struct virtque
if (vq->num_free < out + in) {
pr_debug("Can't add buf len %i - avail = %i\n",
out + in, vq->num_free);
- /* FIXME: for historical reasons, we force a notify here if
- * there are outgoing parts to the buffer. Presumably the
- * host should service the ring ASAP. */
- if (out)
- vq->notify(&vq->vq);
END_USE(vq);
return -ENOSPC;
}
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