[PATCH v6 11/12] drm/xe/madvise: Enable purgeable buffer object IOCTL support

[Arvind Yadav <arvind.yadav@intel.com>]

Hook the madvise_purgeable() handler into the madvise IOCTL now that all
supporting infrastructure is complete:

 - Core purge implementation (patch 3)
 - BO state tracking and helpers (patches 1-2)
 - Per-VMA purgeable state tracking (patch 6)
 - Shrinker integration for memory reclamation (patch 10)

This final patch enables userspace to use the DRM_XE_VMA_ATTR_PURGEABLE_STATE
madvise type to mark buffers as WILLNEED/DONTNEED and receive the retained
status indicating whether buffers were purged.

The feature was kept disabled in earlier patches to maintain bisectability
and ensure all components are in place before exposing to userspace.

Userspace can detect kernel support for purgeable BOs by checking the
DRM_XE_QUERY_CONFIG_FLAG_HAS_PURGING_SUPPORT flag in the query_config
response.

v6:
  - Add DRM_XE_QUERY_CONFIG_FLAG_HAS_PURGING_SUPPORT for userspace
    feature detection. (Jose)

Suggested-by: Matthew Brost <matthew.brost@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Signed-off-by: Arvind Yadav <arvind.yadav@intel.com>
---
 drivers/gpu/drm/xe/xe_query.c      |  2 ++
 drivers/gpu/drm/xe/xe_vm_madvise.c | 22 +++++-----------------
 2 files changed, 7 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_query.c b/drivers/gpu/drm/xe/xe_query.c
index 34db266b723f..e535c77405b9 100644
--- a/drivers/gpu/drm/xe/xe_query.c
+++ b/drivers/gpu/drm/xe/xe_query.c
@@ -340,6 +340,8 @@ static int query_config(struct xe_device *xe, struct drm_xe_device_query *query)
 			DRM_XE_QUERY_CONFIG_FLAG_HAS_NO_COMPRESSION_HINT;
 	config->info[DRM_XE_QUERY_CONFIG_FLAGS] |=
 			DRM_XE_QUERY_CONFIG_FLAG_HAS_LOW_LATENCY;
+	config->info[DRM_XE_QUERY_CONFIG_FLAGS] |=
+			DRM_XE_QUERY_CONFIG_FLAG_HAS_PURGING_SUPPORT;
 	config->info[DRM_XE_QUERY_CONFIG_MIN_ALIGNMENT] =
 		xe->info.vram_flags & XE_VRAM_FLAGS_NEED64K ? SZ_64K : SZ_4K;
 	config->info[DRM_XE_QUERY_CONFIG_VA_BITS] = xe->info.va_bits;
diff --git a/drivers/gpu/drm/xe/xe_vm_madvise.c b/drivers/gpu/drm/xe/xe_vm_madvise.c
index ab83e94980e4..746e9b7b47bb 100644
--- a/drivers/gpu/drm/xe/xe_vm_madvise.c
+++ b/drivers/gpu/drm/xe/xe_vm_madvise.c
@@ -337,18 +337,11 @@ void xe_bo_recompute_purgeable_state(struct xe_bo *bo)
  *
  * Handles DONTNEED/WILLNEED/PURGED states. Tracks if any BO was purged
  * in details->has_purged_bo for later copy to userspace.
- *
- * Note: Marked __maybe_unused until hooked into madvise_funcs[] in the
- * final patch to maintain bisectability. The NULL placeholder in the
- * array ensures proper -EINVAL return for userspace until all supporting
- * infrastructure (shrinker, per-VMA tracking) is complete.
  */
-static void __maybe_unused madvise_purgeable(struct xe_device *xe,
-					     struct xe_vm *vm,
-					     struct xe_vma **vmas,
-					     int num_vmas,
-					     struct drm_xe_madvise *op,
-					     struct xe_madvise_details *details)
+static void madvise_purgeable(struct xe_device *xe, struct xe_vm *vm,
+			      struct xe_vma **vmas, int num_vmas,
+			      struct drm_xe_madvise *op,
+			      struct xe_madvise_details *details)
 {
 	int i;
 
@@ -412,12 +405,7 @@ static const madvise_func madvise_funcs[] = {
 	[DRM_XE_MEM_RANGE_ATTR_PREFERRED_LOC] = madvise_preferred_mem_loc,
 	[DRM_XE_MEM_RANGE_ATTR_ATOMIC] = madvise_atomic,
 	[DRM_XE_MEM_RANGE_ATTR_PAT] = madvise_pat_index,
-	/*
-	 * Purgeable support implemented but not enabled yet to maintain
-	 * bisectability. Will be set to madvise_purgeable() in final patch
-	 * when all infrastructure (shrinker, VMA tracking) is complete.
-	 */
-	[DRM_XE_VMA_ATTR_PURGEABLE_STATE] = NULL,
+	[DRM_XE_VMA_ATTR_PURGEABLE_STATE] = madvise_purgeable,
 };
 
 static u8 xe_zap_ptes_in_madvise_range(struct xe_vm *vm, u64 start, u64 end)
-- 
2.43.0