drm/gem: Take reservation lock for vmap/vunmap operations

The new common dma-buf locking convention will require buffer importers
to hold the reservation lock around mapping operations. Make DRM GEM core
to take the lock around the vmapping operations and update DRM drivers to
use the locked functions for the case where DRM core now holds the lock.
This patch prepares DRM core and drivers to the common dynamic dma-buf
locking convention.

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221017172229.42269-4-dmitry.osipenko@collabora.com

1 files changed, 24 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 86d670c71286..dbee4863e4f7 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1171,6 +1171,8 @@ int drm_gem_vmap(struct drm_gem_object *obj, struct iosys_map *map)
 {
 	int ret;
 
+	dma_resv_assert_held(obj->resv);
+
 	if (!obj->funcs->vmap)
 		return -EOPNOTSUPP;
 
@@ -1186,6 +1188,8 @@ EXPORT_SYMBOL(drm_gem_vmap);
 
 void drm_gem_vunmap(struct drm_gem_object *obj, struct iosys_map *map)
 {
+	dma_resv_assert_held(obj->resv);
+
 	if (iosys_map_is_null(map))
 		return;
 
@@ -1197,6 +1201,26 @@ void drm_gem_vunmap(struct drm_gem_object *obj, struct iosys_map *map)
 }
 EXPORT_SYMBOL(drm_gem_vunmap);
 
+int drm_gem_vmap_unlocked(struct drm_gem_object *obj, struct iosys_map *map)
+{
+	int ret;
+
+	dma_resv_lock(obj->resv, NULL);
+	ret = drm_gem_vmap(obj, map);
+	dma_resv_unlock(obj->resv);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_gem_vmap_unlocked);
+
+void drm_gem_vunmap_unlocked(struct drm_gem_object *obj, struct iosys_map *map)
+{
+	dma_resv_lock(obj->resv, NULL);
+	drm_gem_vunmap(obj, map);
+	dma_resv_unlock(obj->resv);
+}
+EXPORT_SYMBOL(drm_gem_vunmap_unlocked);
+
 /**
  * drm_gem_lock_reservations - Sets up the ww context and acquires
  * the lock on an array of GEM objects.