[PATCH net-next 2/3] vhost: introduce vhost_vq_more_avail()

Jason Wang
2015-11-25T07:12:59Z

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/vhost.c | 26 +++++++++++++++++---------
drivers/vhost/vhost.h | 1 +
2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 163b365..b86c5aa 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1633,10 +1633,25 @@ void vhost_add_used_and_signal_n(struct vhost_dev *dev,
}
EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);

+bool vhost_vq_more_avail(struct vhost_dev *dev, struct vhost_virtqueue *vq)
+{
+ __virtio16 avail_idx;
+ int r;
+
+ r = __get_user(avail_idx, &vq->avail->idx);
+ if (r) {
+ vq_err(vq, "Failed to check avail idx at %p: %d\n",
+ &vq->avail->idx, r);
+ return false;
+ }
+
+ return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
+}
+EXPORT_SYMBOL_GPL(vhost_vq_more_avail);
+
/* OK, now we need to know about added descriptors. */
bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
- __virtio16 avail_idx;
int r;

if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
@@ -1660,14 +1675,7 @@ bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
/* They could have slipped one in as we were doing that: make
* sure it's written, then check again. */
smp_mb();
- r = __get_user(avail_idx, &vq->avail->idx);
- if (r) {
- vq_err(vq, "Failed to check avail idx at %p: %d\n",
- &vq->avail->idx, r);
- return false;
- }
-
- return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
+ return vhost_vq_more_avail(dev, vq);
}
EXPORT_SYMBOL_GPL(vhost_enable_notify);

diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 43284ad..2f3c57c 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -159,6 +159,7 @@ void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
struct vring_used_elem *heads, unsigned count);
void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
+bool vhost_vq_more_avail(struct vhost_dev *, struct vhost_virtqueue *);
bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);

int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
--
2.5.0