drm/xe/uapi: Be more specific about the vm_bind prefetch region

Let's bring a bit of clarity on this 'region' field that is
part of vm_bind operation struct. Rename and document to make
it more than obvious that it is a region instance and not a
mask and also that it should only be used with the prefetch
operation itself.
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Francois Dugast <francois.dugast@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>

drivers/gpu/drm/xe/xe_vm.c

@@ -2160,7 +2160,8 @@ static void print_op(struct xe_device *xe, struct drm_gpuva_op *op)
 static struct drm_gpuva_ops *
 vm_bind_ioctl_ops_create(struct xe_vm *vm, struct xe_bo *bo,
 			 u64 bo_offset_or_userptr, u64 addr, u64 range,
-			 u32 operation, u32 flags, u8 tile_mask, u32 region)
+			 u32 operation, u32 flags, u8 tile_mask,
+			 u32 prefetch_region)
 {
 	struct drm_gem_object *obj = bo ? &bo->ttm.base : NULL;
 	struct drm_gpuva_ops *ops;
@@ -2215,7 +2216,7 @@ vm_bind_ioctl_ops_create(struct xe_vm *vm, struct xe_bo *bo,
 			struct xe_vma_op *op = gpuva_op_to_vma_op(__op);
 
 			op->tile_mask = tile_mask;
-			op->prefetch.region = region;
+			op->prefetch.region = prefetch_region;
 		}
 		break;
 	case DRM_XE_VM_BIND_OP_UNMAP_ALL:
@@ -2881,7 +2882,7 @@ static int vm_bind_ioctl_check_args(struct xe_device *xe,
 		u32 flags = (*bind_ops)[i].flags;
 		u32 obj = (*bind_ops)[i].obj;
 		u64 obj_offset = (*bind_ops)[i].obj_offset;
-		u32 region = (*bind_ops)[i].region;
+		u32 prefetch_region = (*bind_ops)[i].prefetch_mem_region_instance;
 		bool is_null = flags & DRM_XE_VM_BIND_FLAG_NULL;
 
 		if (i == 0) {
@@ -2915,9 +2916,9 @@ static int vm_bind_ioctl_check_args(struct xe_device *xe,
 				 op == DRM_XE_VM_BIND_OP_MAP_USERPTR) ||
 		    XE_IOCTL_DBG(xe, obj &&
 				 op == DRM_XE_VM_BIND_OP_PREFETCH) ||
-		    XE_IOCTL_DBG(xe, region &&
+		    XE_IOCTL_DBG(xe, prefetch_region &&
 				 op != DRM_XE_VM_BIND_OP_PREFETCH) ||
-		    XE_IOCTL_DBG(xe, !(BIT(region) &
+		    XE_IOCTL_DBG(xe, !(BIT(prefetch_region) &
 				       xe->info.mem_region_mask)) ||
 		    XE_IOCTL_DBG(xe, obj &&
 				 op == DRM_XE_VM_BIND_OP_UNMAP)) {
@@ -3099,11 +3100,11 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 		u32 flags = bind_ops[i].flags;
 		u64 obj_offset = bind_ops[i].obj_offset;
 		u8 tile_mask = bind_ops[i].tile_mask;
-		u32 region = bind_ops[i].region;
+		u32 prefetch_region = bind_ops[i].prefetch_mem_region_instance;
 
 		ops[i] = vm_bind_ioctl_ops_create(vm, bos[i], obj_offset,
 						  addr, range, op, flags,
-						  tile_mask, region);
+						  tile_mask, prefetch_region);
 		if (IS_ERR(ops[i])) {
 			err = PTR_ERR(ops[i]);
 			ops[i] = NULL;

include/uapi/drm/xe_drm.h

@@ -673,8 +673,12 @@ struct drm_xe_vm_bind_op {
 	/** @flags: Bind flags */
 	__u32 flags;
 
-	/** @mem_region: Memory region to prefetch VMA to, instance not a mask */
-	__u32 region;
+	/**
+	 * @prefetch_mem_region_instance: Memory region to prefetch VMA to.
+	 * It is a region instance, not a mask.
+	 * To be used only with %DRM_XE_VM_BIND_OP_PREFETCH operation.
+	 */
+	__u32 prefetch_mem_region_instance;
 
 	/** @reserved: Reserved */
 	__u64 reserved[2];