vfio: Don't leak a group reference if the group already exists

If vfio_create_group() searches the group list and returns an already
existing group it does not put back the iommu_group reference that the
caller passed in.

Change the semantic of vfio_create_group() to not move the reference in
from the caller, but instead obtain a new reference inside and leave the
caller's reference alone. The two callers must now call iommu_group_put().

This is an unlikely race as the only caller that could hit it has already
searched the group list before attempting to create the group.

Fixes: cba3345cc494 ("vfio: VFIO core")
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alex Williamson <[email protected]>

0 files changed, 0 insertions, 0 deletions