drm/i915/ttm: Fix illegal addition to shrinker list

There's a small window of opportunity during which the adjust_lru()
function can be called with a GEM refcount of zero from the TTM
eviction code. This results in a kernel BUG().

Ensure that we don't attempt to modify the GEM shrinker lists unless
we have a GEM refcount.

Fixes: ebd4a8ec7799 ("drm/i915/ttm: move shrinker management into adjust_lru")
Signed-off-by: Thomas Hellström <[email protected]>
Reviewed-by: Matthew Auld <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

0 files changed, 0 insertions, 0 deletions