drm/xe: Don't transfer shrinker pages for pinned bos on purgeable state change

Pinned bos have their pages removed from the shrinker's shrinkable /
purgeable counts on pin, and added back on unpin according to the
bo's purgeable state at that time.

However, xe_bo_set_purgeable_shrinker() unconditionally transfers
pages between the shrinkable and purgeable counts. If the purgeable
state of a pinned bo changes, for example by userspace madvising
DONTNEED on a VMA of a bo that is also pinned as a scanout buffer,
this underflows one count and, after unpin, leaves the other one
permanently inflated.

Only update the purgeable flag for pinned bos, and leave the page
accounting to unpin.

Fixes: 536a2ead3a8f ("drm/xe/bo: Add purgeable shrinker state helpers")
Cc: Arvind Yadav <arvind.yadav@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: intel-xe@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v7.1+
Assisted-by: LLM
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patch.msgid.link/20261009070053.7790-1-thomas.hellstrom@linux.intel.com
(cherry picked from commit afe6bc012034123fd838328668e609bf57e46bd3)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

0 files changed, 0 insertions, 0 deletions