This patch introduces a helper which will return true if we're sure that the available ring is empty for a specific vq. When we're not sure, e.g vq access failure, return false instead. This could be used for busy polling code to exit the busy loop.
Unified · Split
| @@ -1658,6 +1658,20 @@ void vhost_add_used_and_signal_n(struct vhost_dev *dev, · 1657 unmodified lines | |||
| 1658 | } | 1658 | } |
| 1659 | EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n); | 1659 | EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n); |
| 1660 | 1660 | ||
| 1661 | /* return true if we're sure that avaiable ring is empty */ | ||
| 1662 | bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq) | ||
| 1663 | { | ||
| 1664 | __virtio16 avail_idx; | ||
| 1665 | int r; | ||
| 1666 | |||
| 1667 | r = __get_user(avail_idx, &vq->avail->idx); | ||
| 1668 | if (r) | ||
| 1669 | return false; | ||
| 1670 | |||
| 1671 | return vhost16_to_cpu(vq, avail_idx) == vq->avail_idx; | ||
| 1672 | } | ||
| 1673 | EXPORT_SYMBOL_GPL(vhost_vq_avail_empty); | ||
| 1674 | |||
| 1661 | /* OK, now we need to know about added descriptors. */ | 1675 | /* OK, now we need to know about added descriptors. */ |
| 1662 | bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) | 1676 | bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
| 1663 | { | 1677 | { |
| @@ -159,6 +159,7 @@ void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *, · 158 unmodified lines | |||
| 159 | struct vring_used_elem *heads, unsigned count); | 159 | struct vring_used_elem *heads, unsigned count); |
| 160 | void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); | 160 | void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); |
| 161 | void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *); | 161 | void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *); |
| 162 | bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *); | ||
| 162 | bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *); | 163 | bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *); |
| 163 | 164 | ||
| 164 | int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, | 165 | int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, |