drm/nouveau/core/memory: add reference counting

We need to be able to prevent memory from being freed while it's still
mapped in a GPU's address-space.

Will be used by upcoming MMU changes.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
This commit is contained in:
Ben Skeggs 2017-11-01 03:56:19 +10:00
commit 997a89003c
19 changed files with 57 additions and 37 deletions