Commit 805bb6c1 authored by Jason Gunthorpe's avatar Jason Gunthorpe Committed by Alex Williamson
Browse files

vfio: Split up vfio_group_get_device_fd() 



The split follows the pairing with the destroy functions:

 - vfio_group_get_device_fd() destroyed by close()

 - vfio_device_open() destroyed by vfio_device_fops_release()

 - vfio_device_assign_container() destroyed by
   vfio_group_try_dissolve_container()

The next patch will put a lock around vfio_device_assign_container().

Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Tested-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Tested-by: default avatarMatthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/3-v2-d035a1842d81+1bf-vfio_group_locking_jgg@nvidia.com


Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent c6f4860e

drivers/vfio/vfio.c

+56 −23
Original line number Diff line number Diff line
@@ -1064,12 +1064,9 @@ static bool vfio_assert_device_open(struct vfio_device *device) 
	return !WARN_ON_ONCE(!READ_ONCE(device->open_count));

}



static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)

static int vfio_device_assign_container(struct vfio_device *device)

{

	struct vfio_device *device;

	struct file *filep;

	int fdno;

	int ret = 0;

	struct vfio_group *group = device->group;



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

	    !group->container->iommu_driver)
@@ -1078,13 +1075,22 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) 
	if (group->type == VFIO_NO_IOMMU && !capable(CAP_SYS_RAWIO))

		return -EPERM;



	device = vfio_device_get_from_name(group, buf);

	if (IS_ERR(device))

		return PTR_ERR(device);

	atomic_inc(&group->container_users);

	return 0;

}



static struct file *vfio_device_open(struct vfio_device *device)

{

	struct file *filep;

	int ret;



	ret = vfio_device_assign_container(device);

	if (ret)

		return ERR_PTR(ret);



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

		ret = -ENODEV;

		goto err_device_put;

		goto err_unassign_container;

	}



	mutex_lock(&device->dev_set->lock);
@@ -1100,15 +1106,11 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) 
	 * We can't use anon_inode_getfd() because we need to modify

	 * the f_mode flags directly to allow more than just ioctls

	 */

	fdno = ret = get_unused_fd_flags(O_CLOEXEC);

	if (ret < 0)

		goto err_close_device;



	filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops,

				   device, O_RDWR);

	if (IS_ERR(filep)) {

		ret = PTR_ERR(filep);

		goto err_fd;

		goto err_close_device;

	}



	/*
@@ -1118,17 +1120,15 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) 
	 */

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



	atomic_inc(&group->container_users);



	fd_install(fdno, filep);



	if (group->type == VFIO_NO_IOMMU)

	if (device->group->type == VFIO_NO_IOMMU)

		dev_warn(device->dev, "vfio-noiommu device opened by user "

			 "(%s:%d)\n", current->comm, task_pid_nr(current));

	return fdno;

	/*

	 * On success the ref of device is moved to the file and

	 * put in vfio_device_fops_release()

	 */

	return filep;



err_fd:

	put_unused_fd(fdno);

err_close_device:

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

	if (device->open_count == 1 && device->ops->close_device)
@@ -1137,7 +1137,40 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) 
	device->open_count--;

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

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

err_device_put:

err_unassign_container:

	vfio_group_try_dissolve_container(device->group);

	return ERR_PTR(ret);

}



static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)

{

	struct vfio_device *device;

	struct file *filep;

	int fdno;

	int ret;



	device = vfio_device_get_from_name(group, buf);

	if (IS_ERR(device))

		return PTR_ERR(device);



	fdno = get_unused_fd_flags(O_CLOEXEC);

	if (fdno < 0) {

		ret = fdno;

		goto err_put_device;

	}



	filep = vfio_device_open(device);

	if (IS_ERR(filep)) {

		ret = PTR_ERR(filep);

		goto err_put_fdno;

	}



	fd_install(fdno, filep);

	return fdno;



err_put_fdno:

	put_unused_fd(fdno);

err_put_device:

	vfio_device_put(device);

	return ret;

}