Commit d9065f44 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'vfio-v4.2-rc5' of git://github.com/awilliam/linux-vfio 

Pull VFIO fix from Alex Williamson:
 "Fix a lockdep reported deadlock in device open error path"

* tag 'vfio-v4.2-rc5' of git://github.com/awilliam/linux-vfio:
  vfio: Fix lockdep issue
parents 733db573 4bc94d5d

drivers/vfio/vfio.c

+54 −37
Original line number Diff line number Diff line
@@ -689,6 +689,23 @@ struct vfio_device *vfio_device_get_from_dev(struct device *dev) 
}

EXPORT_SYMBOL_GPL(vfio_device_get_from_dev);



static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group,

						     char *buf)

{

	struct vfio_device *device;



	mutex_lock(&group->device_lock);

	list_for_each_entry(device, &group->device_list, group_next) {

		if (!strcmp(dev_name(device->dev), buf)) {

			vfio_device_get(device);

			break;

		}

	}

	mutex_unlock(&group->device_lock);



	return device;

}



/*

 * Caller must hold a reference to the vfio_device

 */
@@ -1198,20 +1215,22 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) 
{

	struct vfio_device *device;

	struct file *filep;

	int ret = -ENODEV;

	int ret;



	if (0 == atomic_read(&group->container_users) ||

	    !group->container->iommu_driver || !vfio_group_viable(group))

		return -EINVAL;



	mutex_lock(&group->device_lock);

	list_for_each_entry(device, &group->device_list, group_next) {

		if (strcmp(dev_name(device->dev), buf))

			continue;

	device = vfio_device_get_from_name(group, buf);

	if (!device)

		return -ENODEV;



	ret = device->ops->open(device->device_data);

		if (ret)

			break;

	if (ret) {

		vfio_device_put(device);

		return ret;

	}



	/*

	 * We can't use anon_inode_getfd() because we need to modify

	 * the f_mode flags directly to allow more than just ioctls
@@ -1219,7 +1238,8 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) 
	ret = get_unused_fd_flags(O_CLOEXEC);

	if (ret < 0) {

		device->ops->release(device->device_data);

			break;

		vfio_device_put(device);

		return ret;

	}



	filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops,
@@ -1228,7 +1248,8 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) 
		put_unused_fd(ret);

		ret = PTR_ERR(filep);

		device->ops->release(device->device_data);

			break;

		vfio_device_put(device);

		return ret;

	}



	/*
@@ -1238,13 +1259,9 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) 
	 */

	filep->f_mode |= (FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);



		vfio_device_get(device);

	atomic_inc(&group->container_users);



	fd_install(ret, filep);

		break;

	}

	mutex_unlock(&group->device_lock);



	return ret;

}