cgroup/dmem: Introduce struct dmem_cgroup_init for region initialization

Replace the bare u64 size argument to dmem_cgroup_register_region() and
drmm_cgroup_register_region() with a const struct dmem_cgroup_init *
pointer. The struct currently carries only the size field, but using a
struct makes the API extensible: future callers can supply additional
initialization parameters without adding more positional arguments.

Update all in-tree callers (amdgpu, xe) to use a compound-literal
initializer.

v5:
- Commit introduced.

Assisted-by: GitHub_Copilot:claude-sonnet-4.6
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Tested-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Link: https://patch.msgid.link/20260725100036.2372-3-thomas.hellstrom@linux.intel.com
Acked-by: Dave Airlie <airlied@redhat.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>

4 files changed, 20 insertions, 6 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
index ac3f71d77140..08f05c3aed1d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
@@ -23,6 +23,7 @@
  */
 
 #include <linux/dma-mapping.h>
+#include <linux/cgroup_dmem.h>
 #include <drm/ttm/ttm_range_manager.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_buddy.h>
@@ -932,7 +933,10 @@ int amdgpu_vram_mgr_init(struct amdgpu_device *adev)
 	if (err)
 		return err;
 
-	man->cg = drmm_cgroup_register_region(adev_to_drm(adev), "vram", adev->gmc.real_vram_size);
+	man->cg = drmm_cgroup_register_region(adev_to_drm(adev), "vram",
+					      &(struct dmem_cgroup_init){
+						.size = adev->gmc.real_vram_size,
+					      });
 	if (IS_ERR(man->cg))
 		return PTR_ERR(man->cg);
 
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 1ff0bf7cba6a..3c570f9393b9 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -960,17 +960,19 @@ static void drmm_cg_unregister_region(struct drm_device *dev, void *arg)
  * drmm_cgroup_register_region - Register a region of a DRM device to cgroups
  * @dev: device for region
  * @region_name: Region name for registering
- * @size: Size of region in bytes
+ * @init: Initialization parameters for the region.
  *
  * This decreases the ref-count of @dev by one. The device is destroyed if the
  * ref-count drops to zero.
  */
-struct dmem_cgroup_region *drmm_cgroup_register_region(struct drm_device *dev, const char *region_name, u64 size)
+struct dmem_cgroup_region *
+drmm_cgroup_register_region(struct drm_device *dev, const char *region_name,
+			    const struct dmem_cgroup_init *init)
 {
 	struct dmem_cgroup_region *region;
 	int ret;
 
-	region = dmem_cgroup_register_region(size, "drm/%s/%s", dev->unique, region_name);
+	region = dmem_cgroup_register_region(init, "drm/%s/%s", dev->unique, region_name);
 	if (IS_ERR_OR_NULL(region))
 		return region;
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_ttm.c b/drivers/gpu/drm/nouveau/nouveau_ttm.c
index 860bca7e3ce2..cfc0868e2dd3 100644
--- a/drivers/gpu/drm/nouveau/nouveau_ttm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_ttm.c
@@ -23,6 +23,7 @@
  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
+#include <linux/cgroup_dmem.h>
 #include <linux/limits.h>
 
 #include <drm/ttm/ttm_range_manager.h>
@@ -189,7 +190,9 @@ nouveau_ttm_init_vram(struct nouveau_drm *drm)
 		man->func = &nouveau_vram_manager;
 
 		man->cg = drmm_cgroup_register_region(drm->dev, "vram",
-						      drm->gem.vram_available);
+						      &(struct dmem_cgroup_init){
+							      .size = drm->gem.vram_available
+						      });
 		if (IS_ERR(man->cg))
 			return PTR_ERR(man->cg);
 
diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
index b518f7dec680..308fda4248eb 100644
--- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
+++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
@@ -4,6 +4,8 @@
  * Copyright (C) 2021-2022 Red Hat
  */
 
+#include <linux/cgroup_dmem.h>
+
 #include <drm/drm_managed.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_buddy.h>
@@ -303,7 +305,10 @@ int __xe_ttm_vram_mgr_init(struct xe_device *xe, struct xe_ttm_vram_mgr *mgr,
 	int err;
 
 	name = mem_type == XE_PL_VRAM0 ? "vram0" : "vram1";
-	man->cg = drmm_cgroup_register_region(&xe->drm, name, size);
+	man->cg = drmm_cgroup_register_region(&xe->drm, name,
+					      &(struct dmem_cgroup_init){
+						.size = size,
+					      });
 	if (IS_ERR(man->cg))
 		return PTR_ERR(man->cg);