diff options
Diffstat (limited to 'drivers/vhost/vhost.c')
| -rw-r--r-- | drivers/vhost/vhost.c | 28 |
1 files changed, 6 insertions, 22 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index e4613a3c362d..9cb3f722dce1 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -308,7 +308,6 @@ static void vhost_vq_reset(struct vhost_dev *dev, vq->avail = NULL; vq->used = NULL; vq->last_avail_idx = 0; - vq->last_used_event = 0; vq->avail_idx = 0; vq->last_used_idx = 0; vq->signalled_used = 0; @@ -1402,7 +1401,7 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) r = -EINVAL; break; } - vq->last_avail_idx = vq->last_used_event = s.num; + vq->last_avail_idx = s.num; /* Forget the cached index value. */ vq->avail_idx = vq->last_avail_idx; break; @@ -2241,6 +2240,10 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) __u16 old, new; __virtio16 event; bool v; + /* Flush out used index updates. This is paired + * with the barrier that the Guest executes when enabling + * interrupts. */ + smp_mb(); if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) && unlikely(vq->avail_idx == vq->last_avail_idx)) @@ -2248,10 +2251,6 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) { __virtio16 flags; - /* Flush out used index updates. This is paired - * with the barrier that the Guest executes when enabling - * interrupts. */ - smp_mb(); if (vhost_get_avail(vq, flags, &vq->avail->flags)) { vq_err(vq, "Failed to get flags"); return true; @@ -2266,26 +2265,11 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) if (unlikely(!v)) return true; - /* We're sure if the following conditions are met, there's no - * need to notify guest: - * 1) cached used event is ahead of new - * 2) old to new updating does not cross cached used event. */ - if (vring_need_event(vq->last_used_event, new + vq->num, new) && - !vring_need_event(vq->last_used_event, new, old)) - return false; - - /* Flush out used index updates. This is paired - * with the barrier that the Guest executes when enabling - * interrupts. */ - smp_mb(); - if (vhost_get_avail(vq, event, vhost_used_event(vq))) { vq_err(vq, "Failed to get used event idx"); return true; } - vq->last_used_event = vhost16_to_cpu(vq, event); - - return vring_need_event(vq->last_used_event, new, old); + return vring_need_event(vhost16_to_cpu(vq, event), new, old); } /* This actually signals the guest, using eventfd. */ |