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>

2 files changed, 16 insertions, 4 deletions

diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index e09559495c5b..b23830494ed4 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -34,6 +34,7 @@
 
 #include <drm/drm_device.h>
 
+struct dmem_cgroup_init;
 struct dmem_cgroup_region;
 struct drm_fb_helper;
 struct drm_fb_helper_surface_size;
@@ -433,7 +434,8 @@ void *__devm_drm_dev_alloc(struct device *parent,
 
 struct dmem_cgroup_region *
 drmm_cgroup_register_region(struct drm_device *dev,
-			    const char *region_name, u64 size);
+			    const char *region_name,
+			    const struct dmem_cgroup_init *init);
 
 /**
  * devm_drm_dev_alloc - Resource managed allocation of a &drm_device instance
diff --git a/include/linux/cgroup_dmem.h b/include/linux/cgroup_dmem.h
index 9d72457c4cb9..0575bab38d24 100644
--- a/include/linux/cgroup_dmem.h
+++ b/include/linux/cgroup_dmem.h
@@ -14,8 +14,18 @@ struct dmem_cgroup_pool_state;
 /* Opaque definition of a cgroup region, used internally */
 struct dmem_cgroup_region;
 
+/**
+ * struct dmem_cgroup_init - Initialization parameters for a dmem cgroup region.
+ * @size: Size of the region in bytes.
+ */
+struct dmem_cgroup_init {
+	u64 size;
+};
+
 #if IS_ENABLED(CONFIG_CGROUP_DMEM)
-struct dmem_cgroup_region *dmem_cgroup_register_region(u64 size, const char *name_fmt, ...) __printf(2,3);
+struct dmem_cgroup_region *
+dmem_cgroup_register_region(const struct dmem_cgroup_init *init,
+			    const char *name_fmt, ...) __printf(2, 3);
 void dmem_cgroup_unregister_region(struct dmem_cgroup_region *region);
 int dmem_cgroup_try_charge(struct dmem_cgroup_region *region, u64 size,
 			   struct dmem_cgroup_pool_state **ret_pool,
@@ -33,8 +43,8 @@ struct dmem_cgroup_pool_state *dmem_cgroup_get_common_ancestor(struct dmem_cgrou
 
 void dmem_cgroup_pool_state_put(struct dmem_cgroup_pool_state *pool);
 #else
-static inline __printf(2,3) struct dmem_cgroup_region *
-dmem_cgroup_register_region(u64 size, const char *name_fmt, ...)
+static inline __printf(2, 3) struct dmem_cgroup_region *
+dmem_cgroup_register_region(const struct dmem_cgroup_init *init, const char *name_fmt, ...)
 {
 	return NULL;
 }