On 3/13/2021 2:55 AM, Jason Gunthorpe wrote:
The vfio_device->group value has a get obtained during vfio_add_group_dev() which gets moved from the stack to vfio_device->group in vfio_group_create_device(). The reference remains until we reach the end of vfio_del_group_dev() when it is put back. Thus anything that already has a kref on the vfio_device is guaranteed a valid group pointer. Remove all the extra reference traffic. It is tricky to see, but the get at the start of vfio_del_group_dev() is actually pairing with the put hidden inside vfio_device_put() a few lines below. A later patch merges vfio_group_create_device() into vfio_add_group_dev() which makes the ownership and error flow on the create side easier to follow. Reviewed-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx> --- drivers/vfio/vfio.c | 21 ++------------------- 1 file changed, 2 insertions(+), 19 deletions(-)
Looks good, Reviewed-by: Max Gurtovoy <mgurtovoy@xxxxxxxxxx>
