Commit 294aaccb authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

vfio: Move vfio_device driver open/close code to a function 

This error unwind is getting complicated. Move all the code into two
pair'd function. The functions should be called when the open_count == 1
after incrementing/before decrementing.

Link: https://lore.kernel.org/r/1-v4-42cd2eb0e3eb+335a-vfio_iommufd_jgg@nvidia.com


Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Reviewed-by: default avatarYi Liu <yi.l.liu@intel.com>
Reviewed-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Tested-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Tested-by: default avatarYi Liu <yi.l.liu@intel.com>
Tested-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Tested-by: default avatarLixiao Yang <lixiao.yang@intel.com>
Tested-by: default avatarMatthew Rosato <mjrosato@linux.ibm.com>
Tested-by: default avatarYu He <yu.he@intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 2a54e347

drivers/vfio/vfio_main.c

+53 −42
Original line number Diff line number Diff line
@@ -734,40 +734,68 @@ bool vfio_assert_device_open(struct vfio_device *device) 
	return !WARN_ON_ONCE(!READ_ONCE(device->open_count));

}



static struct file *vfio_device_open(struct vfio_device *device)

static int vfio_device_first_open(struct vfio_device *device)

{

	struct file *filep;

	int ret;



	mutex_lock(&device->group->group_lock);

	ret = vfio_device_assign_container(device);

	mutex_unlock(&device->group->group_lock);

	if (ret)

		return ERR_PTR(ret);

	lockdep_assert_held(&device->dev_set->lock);



	if (!try_module_get(device->dev->driver->owner)) {

		ret = -ENODEV;

		goto err_unassign_container;

	}

	if (!try_module_get(device->dev->driver->owner))

		return -ENODEV;



	mutex_lock(&device->dev_set->lock);

	device->open_count++;

	if (device->open_count == 1) {

	/*

		 * Here we pass the KVM pointer with the group under the read

		 * lock.  If the device driver will use it, it must obtain a

		 * reference and release it during close_device.

	 * Here we pass the KVM pointer with the group under the lock.  If the

	 * device driver will use it, it must obtain a reference and release it

	 * during close_device.

	 */

	mutex_lock(&device->group->group_lock);

	device->kvm = device->group->kvm;



	if (device->ops->open_device) {

		ret = device->ops->open_device(device);

		if (ret)

				goto err_undo_count;

			goto err_module_put;

	}

	vfio_device_container_register(device);

	mutex_unlock(&device->group->group_lock);

	return 0;



err_module_put:

	device->kvm = NULL;

	mutex_unlock(&device->group->group_lock);

	module_put(device->dev->driver->owner);

	return ret;

}



static void vfio_device_last_close(struct vfio_device *device)

{

	lockdep_assert_held(&device->dev_set->lock);



	mutex_lock(&device->group->group_lock);

	vfio_device_container_unregister(device);

	if (device->ops->close_device)

		device->ops->close_device(device);

	device->kvm = NULL;

	mutex_unlock(&device->group->group_lock);

	module_put(device->dev->driver->owner);

}



static struct file *vfio_device_open(struct vfio_device *device)

{

	struct file *filep;

	int ret;



	mutex_lock(&device->group->group_lock);

	ret = vfio_device_assign_container(device);

	mutex_unlock(&device->group->group_lock);

	if (ret)

		return ERR_PTR(ret);



	mutex_lock(&device->dev_set->lock);

	device->open_count++;

	if (device->open_count == 1) {

		ret = vfio_device_first_open(device);

		if (ret)

			goto err_unassign_container;

	}

	mutex_unlock(&device->dev_set->lock);
@@ -800,20 +828,11 @@ static struct file *vfio_device_open(struct vfio_device *device) 


err_close_device:

	mutex_lock(&device->dev_set->lock);

	mutex_lock(&device->group->group_lock);

	if (device->open_count == 1 && device->ops->close_device) {

		device->ops->close_device(device);



		vfio_device_container_unregister(device);

	}

err_undo_count:

	mutex_unlock(&device->group->group_lock);

	if (device->open_count == 1)

		vfio_device_last_close(device);

err_unassign_container:

	device->open_count--;

	if (device->open_count == 0 && device->kvm)

		device->kvm = NULL;

	mutex_unlock(&device->dev_set->lock);

	module_put(device->dev->driver->owner);

err_unassign_container:

	vfio_device_unassign_container(device);

	return ERR_PTR(ret);

}
@@ -1016,19 +1035,11 @@ static int vfio_device_fops_release(struct inode *inode, struct file *filep) 


	mutex_lock(&device->dev_set->lock);

	vfio_assert_device_open(device);

	mutex_lock(&device->group->group_lock);

	if (device->open_count == 1 && device->ops->close_device)

		device->ops->close_device(device);



	vfio_device_container_unregister(device);

	mutex_unlock(&device->group->group_lock);

	if (device->open_count == 1)

		vfio_device_last_close(device);

	device->open_count--;

	if (device->open_count == 0)

		device->kvm = NULL;

	mutex_unlock(&device->dev_set->lock);



	module_put(device->dev->driver->owner);



	vfio_device_unassign_container(device);



	vfio_device_put_registration(device);