drm/nouveau: Remove support for legacy contexts/buffers

Remove nouveau's support for legacy contexts and buffers. It was
required by libdrm earlier than 2.4.33, released in March 2012. A
previous attempt in 2013 to remove the functionality [1] had to be
reverted [2] as there were still users left. Libdrm 2.4.33 is now
almost 11 years old and it is time for userspace to move on.

With the nouveau code gone, we can also remove the driver-feature
bit DRIVER_KMS_LEGACY_CONTEXT.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c510133d93dd6f15ca040733ba7b2891ed61fd1 # 1
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c21eb21cb50d58e7cbdcb8b9e7ff68b85cfa5095 # 2
Link: https://patchwork.freedesktop.org/patch/msgid/20230112133858.17087-1-tzimmermann@suse.de

drivers/gpu/drm/drm_bufs.c

@@ -423,8 +423,7 @@ int drm_legacy_addmap_ioctl(struct drm_device *dev, void *data,
 	if (!(capable(CAP_SYS_ADMIN) || map->type == _DRM_AGP || map->type == _DRM_SHM))
 		return -EPERM;
 
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return -EOPNOTSUPP;
 
 	err = drm_addmap_core(dev, map->offset, map->size, map->type,
@@ -469,8 +468,7 @@ int drm_legacy_getmap_ioctl(struct drm_device *dev, void *data,
 	int idx;
 	int i;
 
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return -EOPNOTSUPP;
 
 	idx = map->offset;
@@ -570,8 +568,7 @@ EXPORT_SYMBOL(drm_legacy_rmmap_locked);
 
 void drm_legacy_rmmap(struct drm_device *dev, struct drm_local_map *map)
 {
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return;
 
 	mutex_lock(&dev->struct_mutex);
@@ -628,8 +625,7 @@ int drm_legacy_rmmap_ioctl(struct drm_device *dev, void *data,
 	struct drm_map_list *r_list;
 	int ret;
 
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return -EOPNOTSUPP;
 
 	mutex_lock(&dev->struct_mutex);

drivers/gpu/drm/drm_context.c

@@ -59,8 +59,7 @@ struct drm_ctx_list {
  */
 void drm_legacy_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
 {
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return;
 
 	mutex_lock(&dev->struct_mutex);
@@ -97,8 +96,7 @@ static int drm_legacy_ctxbitmap_next(struct drm_device * dev)
  */
 void drm_legacy_ctxbitmap_init(struct drm_device * dev)
 {
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return;
 
 	idr_init(&dev->ctx_idr);
@@ -114,8 +112,7 @@ void drm_legacy_ctxbitmap_init(struct drm_device * dev)
  */
 void drm_legacy_ctxbitmap_cleanup(struct drm_device * dev)
 {
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return;
 
 	mutex_lock(&dev->struct_mutex);
@@ -136,8 +133,7 @@ void drm_legacy_ctxbitmap_flush(struct drm_device *dev, struct drm_file *file)
 {
 	struct drm_ctx_list *pos, *tmp;
 
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return;
 
 	mutex_lock(&dev->ctxlist_mutex);
@@ -182,8 +178,7 @@ int drm_legacy_getsareactx(struct drm_device *dev, void *data,
 	struct drm_local_map *map;
 	struct drm_map_list *_entry;
 
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return -EOPNOTSUPP;
 
 	mutex_lock(&dev->struct_mutex);
@@ -230,8 +225,7 @@ int drm_legacy_setsareactx(struct drm_device *dev, void *data,
 	struct drm_local_map *map = NULL;
 	struct drm_map_list *r_list = NULL;
 
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return -EOPNOTSUPP;
 
 	mutex_lock(&dev->struct_mutex);
@@ -335,8 +329,7 @@ int drm_legacy_resctx(struct drm_device *dev, void *data,
 	struct drm_ctx ctx;
 	int i;
 
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return -EOPNOTSUPP;
 
 	if (res->count >= DRM_RESERVED_CONTEXTS) {
@@ -370,8 +363,7 @@ int drm_legacy_addctx(struct drm_device *dev, void *data,
 	struct drm_ctx *ctx = data;
 	int tmp_handle;
 
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return -EOPNOTSUPP;
 
 	tmp_handle = drm_legacy_ctxbitmap_next(dev);
@@ -419,8 +411,7 @@ int drm_legacy_getctx(struct drm_device *dev, void *data,
 {
 	struct drm_ctx *ctx = data;
 
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return -EOPNOTSUPP;
 
 	/* This is 0, because we don't handle any context flags */
@@ -445,8 +436,7 @@ int drm_legacy_switchctx(struct drm_device *dev, void *data,
 {
 	struct drm_ctx *ctx = data;
 
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return -EOPNOTSUPP;
 
 	DRM_DEBUG("%d\n", ctx->handle);
@@ -469,8 +459,7 @@ int drm_legacy_newctx(struct drm_device *dev, void *data,
 {
 	struct drm_ctx *ctx = data;
 
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return -EOPNOTSUPP;
 
 	DRM_DEBUG("%d\n", ctx->handle);
@@ -495,8 +484,7 @@ int drm_legacy_rmctx(struct drm_device *dev, void *data,
 {
 	struct drm_ctx *ctx = data;
 
-	if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
-	    !drm_core_check_feature(dev, DRIVER_LEGACY))
+	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
 		return -EOPNOTSUPP;
 
 	DRM_DEBUG("%d\n", ctx->handle);

drivers/gpu/drm/nouveau/Kconfig

@@ -26,18 +26,6 @@ config DRM_NOUVEAU
 	help
 	  Choose this option for open-source NVIDIA support.
 
-config NOUVEAU_LEGACY_CTX_SUPPORT
-	bool "Nouveau legacy context support"
-	depends on DRM_NOUVEAU
-	select DRM_LEGACY
-	default y
-	help
-	  There was a version of the nouveau DDX that relied on legacy
-	  ctx ioctls not erroring out. But that was back in time a long
-	  ways, so offer a way to disable it now. For uapi compat with
-	  old nouveau ddx this should be on by default, but modern distros
-	  should consider turning it off.
-
 config NOUVEAU_PLATFORM_DRIVER
 	bool "Nouveau (NVIDIA) SoC GPUs"
 	depends on DRM_NOUVEAU && ARCH_TEGRA

drivers/gpu/drm/nouveau/nouveau_drm.c

@@ -1221,13 +1221,9 @@ nouveau_driver_fops = {
 
 static struct drm_driver
 driver_stub = {
-	.driver_features =
-		DRIVER_GEM | DRIVER_MODESET | DRIVER_RENDER
-#if defined(CONFIG_NOUVEAU_LEGACY_CTX_SUPPORT)
-		| DRIVER_KMS_LEGACY_CONTEXT
-#endif
-		,
-
+	.driver_features = DRIVER_GEM |
+			   DRIVER_MODESET |
+			   DRIVER_RENDER,
 	.open = nouveau_drm_open,
 	.postclose = nouveau_drm_postclose,
 	.lastclose = nouveau_vga_lastclose,

include/drm/drm_drv.h

@@ -141,13 +141,6 @@ enum drm_driver_feature {
 	 * Legacy irq support. Only for legacy drivers. Do not use.
 	 */
 	DRIVER_HAVE_IRQ			= BIT(30),
-	/**
-	 * @DRIVER_KMS_LEGACY_CONTEXT:
-	 *
-	 * Used only by nouveau for backwards compatibility with existing
-	 * userspace.  Do not use.
-	 */
-	DRIVER_KMS_LEGACY_CONTEXT	= BIT(31),
 };
 
 /**