virtio,vhost: fixes

More small fixes. Most notably this fixes a messed up ioctl #,
 and a regression in shmem affecting drm users.
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio/vhost fixes from Michael Tsirkin:
 "More small fixes. Most notably this fixes a messed up ioctl number,
  and a regression in shmem affecting drm users"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio_net: adjust the execution order of function `virtnet_close` during freeze
  virtio_input: Improve freeze handling
  vhost: Fix ioctl # for VHOST_[GS]ET_FORK_FROM_OWNER
  Revert "virtio: reject shm region if length is zero"
  vhost/net: Protect ubufs with rcu read lock in vhost_net_ubuf_put()
  virtio_pci: Fix misleading comment for queue vector

drivers/net/virtio_net.c

@@ -5758,14 +5758,15 @@ static void virtnet_freeze_down(struct virtio_device *vdev)
 	disable_rx_mode_work(vi);
 	flush_work(&vi->rx_mode_work);
 
-	netif_tx_lock_bh(vi->dev);
-	netif_device_detach(vi->dev);
-	netif_tx_unlock_bh(vi->dev);
 	if (netif_running(vi->dev)) {
 		rtnl_lock();
 		virtnet_close(vi->dev);
 		rtnl_unlock();
 	}
+
+	netif_tx_lock_bh(vi->dev);
+	netif_device_detach(vi->dev);
+	netif_tx_unlock_bh(vi->dev);
 }
 
 static int init_vqs(struct virtnet_info *vi);

drivers/vhost/net.c

@@ -99,6 +99,7 @@ struct vhost_net_ubuf_ref {
 	atomic_t refcount;
 	wait_queue_head_t wait;
 	struct vhost_virtqueue *vq;
+	struct rcu_head rcu;
 };
 
 #define VHOST_NET_BATCH 64
@@ -250,9 +251,13 @@ vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy)
 
 static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs)
 {
-	int r = atomic_sub_return(1, &ubufs->refcount);
+	int r;
+
+	rcu_read_lock();
+	r = atomic_sub_return(1, &ubufs->refcount);
 	if (unlikely(!r))
 		wake_up(&ubufs->wait);
+	rcu_read_unlock();
 	return r;
 }
 
@@ -265,7 +270,7 @@ static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs)
 static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs)
 {
 	vhost_net_ubuf_put_and_wait(ubufs);
-	kfree(ubufs);
+	kfree_rcu(ubufs, rcu);
 }
 
 static void vhost_net_clear_ubuf_info(struct vhost_net *n)

drivers/virtio/virtio_input.c

@@ -360,11 +360,15 @@ static int virtinput_freeze(struct virtio_device *vdev)
 {
 	struct virtio_input *vi = vdev->priv;
 	unsigned long flags;
+	void *buf;
 
 	spin_lock_irqsave(&vi->lock, flags);
 	vi->ready = false;
 	spin_unlock_irqrestore(&vi->lock, flags);
 
+	virtio_reset_device(vdev);
+	while ((buf = virtqueue_detach_unused_buf(vi->sts)) != NULL)
+		kfree(buf);
 	vdev->config->del_vqs(vdev);
 	return 0;
 }

drivers/virtio/virtio_pci_legacy_dev.c

@@ -140,9 +140,9 @@ EXPORT_SYMBOL_GPL(vp_legacy_set_status);
  * vp_legacy_queue_vector - set the MSIX vector for a specific virtqueue
  * @ldev: the legacy virtio-pci device
  * @index: queue index
- * @vector: the config vector
+ * @vector: the queue vector
  *
- * Returns the config vector read from the device
+ * Returns the queue vector read from the device
  */
 u16 vp_legacy_queue_vector(struct virtio_pci_legacy_device *ldev,
 			   u16 index, u16 vector)

drivers/virtio/virtio_pci_modern_dev.c

@@ -546,9 +546,9 @@ EXPORT_SYMBOL_GPL(vp_modern_set_queue_reset);
  * vp_modern_queue_vector - set the MSIX vector for a specific virtqueue
  * @mdev: the modern virtio-pci device
  * @index: queue index
- * @vector: the config vector
+ * @vector: the queue vector
  *
- * Returns the config vector read from the device
+ * Returns the queue vector read from the device
  */
 u16 vp_modern_queue_vector(struct virtio_pci_modern_device *mdev,
 			   u16 index, u16 vector)

include/linux/virtio_config.h

@@ -328,8 +328,6 @@ static inline
 bool virtio_get_shm_region(struct virtio_device *vdev,
 			   struct virtio_shm_region *region, u8 id)
 {
-	if (!region->len)
-		return false;
 	if (!vdev->config->get_shm_region)
 		return false;
 	return vdev->config->get_shm_region(vdev, region, id);

include/uapi/linux/vhost.h

@@ -260,7 +260,7 @@
  * When fork_owner is set to VHOST_FORK_OWNER_KTHREAD:
  *   - Vhost will create vhost workers as kernel threads.
  */
-#define VHOST_SET_FORK_FROM_OWNER _IOW(VHOST_VIRTIO, 0x83, __u8)
+#define VHOST_SET_FORK_FROM_OWNER _IOW(VHOST_VIRTIO, 0x84, __u8)
 
 /**
  * VHOST_GET_FORK_OWNER - Get the current fork_owner flag for the vhost device.
@@ -268,6 +268,6 @@
  *
  * @return: An 8-bit value indicating the current thread mode.
  */
-#define VHOST_GET_FORK_FROM_OWNER _IOR(VHOST_VIRTIO, 0x84, __u8)
+#define VHOST_GET_FORK_FROM_OWNER _IOR(VHOST_VIRTIO, 0x85, __u8)
 
 #endif