vhost: avoid backend flush on vring ops
vring changes already do a flush internally where appropriate, so we do
not need a second flush.
It's currently not very expensive but a follow-up patch makes flush more
heavy-weight, so remove the extra flush here to avoid regressing
performance if call or kick fds are changed on data path.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index ff6c919..1802ab6 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -942,8 +942,11 @@
return vhost_net_reset_owner(n);
default:
mutex_lock(&n->dev.mutex);
- r = vhost_dev_ioctl(&n->dev, ioctl, arg);
- vhost_net_flush(n);
+ r = vhost_dev_ioctl(&n->dev, ioctl, argp);
+ if (r == -ENOIOCTLCMD)
+ r = vhost_vring_ioctl(&n->dev, ioctl, argp);
+ else
+ vhost_net_flush(n);
mutex_unlock(&n->dev.mutex);
return r;
}
diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index ef88844..33e5f90 100644
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -970,7 +970,10 @@
return vhost_scsi_set_features(vs, features);
default:
mutex_lock(&vs->dev.mutex);
- r = vhost_dev_ioctl(&vs->dev, ioctl, arg);
+ r = vhost_dev_ioctl(&vs->dev, ioctl, argp);
+ /* TODO: flush backend after dev ioctl. */
+ if (r == -ENOIOCTLCMD)
+ r = vhost_vring_ioctl(&vs->dev, ioctl, argp);
mutex_unlock(&vs->dev.mutex);
return r;
}
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 5a3d0f1..34389f7 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -607,7 +607,7 @@
return 0;
}
-static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp)
+long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
{
struct file *eventfp, *filep = NULL;
bool pollstart = false, pollstop = false;
@@ -802,9 +802,8 @@
}
/* Caller must have device mutex */
-long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg)
+long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
{
- void __user *argp = (void __user *)arg;
struct file *eventfp, *filep = NULL;
struct eventfd_ctx *ctx = NULL;
u64 p;
@@ -875,7 +874,7 @@
fput(filep);
break;
default:
- r = vhost_set_vring(d, ioctl, argp);
+ r = -ENOIOCTLCMD;
break;
}
done:
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 5e19e3d..2639c58 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -164,7 +164,8 @@
long vhost_dev_reset_owner(struct vhost_dev *);
void vhost_dev_cleanup(struct vhost_dev *, bool locked);
void vhost_dev_stop(struct vhost_dev *);
-long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);
+long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
+long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
int vhost_vq_access_ok(struct vhost_virtqueue *vq);
int vhost_log_access_ok(struct vhost_dev *);
