vhost: check owner before we overwrite ubuf_info

If device has an owner, we shouldn't touch ubuf_info
since it might be in use.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index b07d96b8c0d1cc2e3a28ae616837db8f8d8a561b..8cf5aece8c84d0a4ec68243f5fdfe2bc08c1ab45 100644 (file)
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -1054,6 +1054,10 @@ static long vhost_net_set_owner(struct vhost_net *n)
        int r;
 
        mutex_lock(&n->dev.mutex);
+       if (vhost_dev_has_owner(&n->dev)) {
+               r = -EBUSY;
+               goto out;
+       }
        r = vhost_net_set_ubuf_info(n);
        if (r)
                goto out;

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index beee7f5787e6c814b2420f745be2555ca6a71af5..60aa5ad09a2fdb74a457ecadf0130f056f114c8e 100644 (file)
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -343,6 +343,12 @@ static int vhost_attach_cgroups(struct vhost_dev *dev)
        return attach.ret;
 }
 
+/* Caller should have device mutex */
+bool vhost_dev_has_owner(struct vhost_dev *dev)
+{
+       return dev->mm;
+}
+
 /* Caller should have device mutex */
 long vhost_dev_set_owner(struct vhost_dev *dev)
 {
@@ -350,7 +356,7 @@ long vhost_dev_set_owner(struct vhost_dev *dev)
        int err;
 
        /* Is there an owner already? */
-       if (dev->mm) {
+       if (vhost_dev_has_owner(dev)) {
                err = -EBUSY;
                goto err_mm;
        }

diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index a7ad63592987f33ed4fd773691b7f5f604220d51..64adcf99ff33893f1eb71b4c181dba4df739a8f3 100644 (file)
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -133,6 +133,7 @@ struct vhost_dev {
 
 long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
 long vhost_dev_set_owner(struct vhost_dev *dev);
+bool vhost_dev_has_owner(struct vhost_dev *dev);
 long vhost_dev_check_owner(struct vhost_dev *);
 struct vhost_memory *vhost_dev_reset_owner_prepare(void);
 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_memory *);