vhost: fix error handling in RESET_OWNER ioctl
RESET_OWNER ioctl would leave the fd in a bad state if
memory allocation failed: device is stopped
but owner is not reset. Make state changes
after allocating memory, such that a failed
ioctl has no effect.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index e34e195..a3645bd 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -967,14 +967,20 @@
struct socket *tx_sock = NULL;
struct socket *rx_sock = NULL;
long err;
+ struct vhost_memory *memory;
mutex_lock(&n->dev.mutex);
err = vhost_dev_check_owner(&n->dev);
if (err)
goto done;
+ memory = vhost_dev_reset_owner_prepare();
+ if (!memory) {
+ err = -ENOMEM;
+ goto done;
+ }
vhost_net_stop(n, &tx_sock, &rx_sock);
vhost_net_flush(n);
- err = vhost_dev_reset_owner(&n->dev);
+ vhost_dev_reset_owner(&n->dev, memory);
vhost_net_vq_reset(n);
done:
mutex_unlock(&n->dev.mutex);
diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
index 91d6f06..be65414 100644
--- a/drivers/vhost/test.c
+++ b/drivers/vhost/test.c
@@ -219,13 +219,20 @@
{
void *priv = NULL;
long err;
+ struct vhost_memory *memory;
+
mutex_lock(&n->dev.mutex);
err = vhost_dev_check_owner(&n->dev);
if (err)
goto done;
+ memory = vhost_dev_reset_owner_prepare();
+ if (!memory) {
+ err = -ENOMEM;
+ goto done;
+ }
vhost_test_stop(n, &priv);
vhost_test_flush(n);
- err = vhost_dev_reset_owner(&n->dev);
+ vhost_dev_reset_owner(&n->dev, memory);
done:
mutex_unlock(&n->dev.mutex);
return err;
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 6dcd81c..749b5ab 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -386,21 +386,19 @@
return err;
}
-/* Caller should have device mutex */
-long vhost_dev_reset_owner(struct vhost_dev *dev)
+struct vhost_memory *vhost_dev_reset_owner_prepare(void)
{
- struct vhost_memory *memory;
+ return kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL);
+}
- /* Restore memory to default empty mapping. */
- memory = kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL);
- if (!memory)
- return -ENOMEM;
-
+/* Caller should have device mutex */
+void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_memory *memory)
+{
vhost_dev_cleanup(dev, true);
+ /* Restore memory to default empty mapping. */
memory->nregions = 0;
RCU_INIT_POINTER(dev->memory, memory);
- return 0;
}
void vhost_dev_stop(struct vhost_dev *dev)
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 1627eec..b58f4ae 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -136,7 +136,8 @@
long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
long vhost_dev_check_owner(struct vhost_dev *);
-long vhost_dev_reset_owner(struct vhost_dev *);
+struct vhost_memory *vhost_dev_reset_owner_prepare(void);
+void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_memory *);
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, void __user *argp);