1 files changed, 45 insertions, 50 deletions

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 4bf0a76bb35e..6a44351e58b7 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -26,6 +26,7 @@
  */
 
 #include <linux/dma-buf.h>
+#include <linux/export.h>
 #include <linux/file.h>
 #include <linux/fs.h>
 #include <linux/iosys-map.h>
@@ -223,23 +224,34 @@ static void drm_gem_object_handle_get(struct drm_gem_object *obj)
 }
 
 /**
- * drm_gem_object_handle_get_unlocked - acquire reference on user-space handles
+ * drm_gem_object_handle_get_if_exists_unlocked - acquire reference on user-space handle, if any
  * @obj: GEM object
  *
- * Acquires a reference on the GEM buffer object's handle. Required
- * to keep the GEM object alive. Call drm_gem_object_handle_put_unlocked()
- * to release the reference.
+ * Acquires a reference on the GEM buffer object's handle. Required to keep
+ * the GEM object alive. Call drm_gem_object_handle_put_if_exists_unlocked()
+ * to release the reference. Does nothing if the buffer object has no handle.
+ *
+ * Returns:
+ * True if a handle exists, or false otherwise
  */
-void drm_gem_object_handle_get_unlocked(struct drm_gem_object *obj)
+bool drm_gem_object_handle_get_if_exists_unlocked(struct drm_gem_object *obj)
 {
 	struct drm_device *dev = obj->dev;
 
 	guard(mutex)(&dev->object_name_lock);
 
-	drm_WARN_ON(dev, !obj->handle_count); /* first ref taken in create-tail helper */
+	/*
+	 * First ref taken during GEM object creation, if any. Some
+	 * drivers set up internal framebuffers with GEM objects that
+	 * do not have a GEM handle. Hence, this counter can be zero.
+	 */
+	if (!obj->handle_count)
+		return false;
+
 	drm_gem_object_handle_get(obj);
+
+	return true;
 }
-EXPORT_SYMBOL(drm_gem_object_handle_get_unlocked);
 
 /**
  * drm_gem_object_handle_free - release resources bound to userspace handles
@@ -272,7 +284,7 @@ static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj)
 }
 
 /**
- * drm_gem_object_handle_put_unlocked - releases reference on user-space handles
+ * drm_gem_object_handle_put_unlocked - releases reference on user-space handle
  * @obj: GEM object
  *
  * Releases a reference on the GEM buffer object's handle. Possibly releases
@@ -283,14 +295,14 @@ void drm_gem_object_handle_put_unlocked(struct drm_gem_object *obj)
 	struct drm_device *dev = obj->dev;
 	bool final = false;
 
-	if (WARN_ON(READ_ONCE(obj->handle_count) == 0))
+	if (drm_WARN_ON(dev, READ_ONCE(obj->handle_count) == 0))
 		return;
 
 	/*
-	* Must bump handle count first as this may be the last
-	* ref, in which case the object would disappear before we
-	* checked for a name
-	*/
+	 * Must bump handle count first as this may be the last
+	 * ref, in which case the object would disappear before
+	 * we checked for a name.
+	 */
 
 	mutex_lock(&dev->object_name_lock);
 	if (--obj->handle_count == 0) {
@@ -303,7 +315,6 @@ void drm_gem_object_handle_put_unlocked(struct drm_gem_object *obj)
 	if (final)
 		drm_gem_object_put(obj);
 }
-EXPORT_SYMBOL(drm_gem_object_handle_put_unlocked);
 
 /*
  * Called at device or object close to release the file's
@@ -315,6 +326,9 @@ drm_gem_object_release_handle(int id, void *ptr, void *data)
 	struct drm_file *file_priv = data;
 	struct drm_gem_object *obj = ptr;
 
+	if (drm_WARN_ON(obj->dev, !data))
+		return 0;
+
 	if (obj->funcs->close)
 		obj->funcs->close(obj, file_priv);
 
@@ -435,7 +449,7 @@ drm_gem_handle_create_tail(struct drm_file *file_priv,
 	idr_preload(GFP_KERNEL);
 	spin_lock(&file_priv->table_lock);
 
-	ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
+	ret = idr_alloc(&file_priv->object_idr, NULL, 1, 0, GFP_NOWAIT);
 
 	spin_unlock(&file_priv->table_lock);
 	idr_preload_end();
@@ -456,6 +470,11 @@ drm_gem_handle_create_tail(struct drm_file *file_priv,
 			goto err_revoke;
 	}
 
+	/* mirrors drm_gem_handle_delete to avoid races */
+	spin_lock(&file_priv->table_lock);
+	obj = idr_replace(&file_priv->object_idr, obj, handle);
+	WARN_ON(obj != NULL);
+	spin_unlock(&file_priv->table_lock);
 	*handlep = handle;
 	return 0;
 
@@ -1220,38 +1239,6 @@ void drm_gem_print_info(struct drm_printer *p, unsigned int indent,
 		obj->funcs->print_info(p, indent, obj);
 }
 
-int drm_gem_pin_locked(struct drm_gem_object *obj)
-{
-	if (obj->funcs->pin)
-		return obj->funcs->pin(obj);
-
-	return 0;
-}
-
-void drm_gem_unpin_locked(struct drm_gem_object *obj)
-{
-	if (obj->funcs->unpin)
-		obj->funcs->unpin(obj);
-}
-
-int drm_gem_pin(struct drm_gem_object *obj)
-{
-	int ret;
-
-	dma_resv_lock(obj->resv, NULL);
-	ret = drm_gem_pin_locked(obj);
-	dma_resv_unlock(obj->resv);
-
-	return ret;
-}
-
-void drm_gem_unpin(struct drm_gem_object *obj)
-{
-	dma_resv_lock(obj->resv, NULL);
-	drm_gem_unpin_locked(obj);
-	dma_resv_unlock(obj->resv);
-}
-
 int drm_gem_vmap_locked(struct drm_gem_object *obj, struct iosys_map *map)
 {
 	int ret;
@@ -1496,12 +1483,14 @@ EXPORT_SYMBOL(drm_gem_lru_move_tail);
  * @nr_to_scan: The number of pages to try to reclaim
  * @remaining: The number of pages left to reclaim, should be initialized by caller
  * @shrink: Callback to try to shrink/reclaim the object.
+ * @ticket: Optional ww_acquire_ctx context to use for locking
  */
 unsigned long
 drm_gem_lru_scan(struct drm_gem_lru *lru,
 		 unsigned int nr_to_scan,
 		 unsigned long *remaining,
-		 bool (*shrink)(struct drm_gem_object *obj))
+		 bool (*shrink)(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket),
+		 struct ww_acquire_ctx *ticket)
 {
 	struct drm_gem_lru still_in_lru;
 	struct drm_gem_object *obj;
@@ -1534,17 +1523,20 @@ drm_gem_lru_scan(struct drm_gem_lru *lru,
 		 */
 		mutex_unlock(lru->lock);
 
+		if (ticket)
+			ww_acquire_init(ticket, &reservation_ww_class);
+
 		/*
 		 * Note that this still needs to be trylock, since we can
 		 * hit shrinker in response to trying to get backing pages
 		 * for this obj (ie. while it's lock is already held)
 		 */
-		if (!dma_resv_trylock(obj->resv)) {
+		if (!ww_mutex_trylock(&obj->resv->lock, ticket)) {
 			*remaining += obj->size >> PAGE_SHIFT;
 			goto tail;
 		}
 
-		if (shrink(obj)) {
+		if (shrink(obj, ticket)) {
 			freed += obj->size >> PAGE_SHIFT;
 
 			/*
@@ -1558,6 +1550,9 @@ drm_gem_lru_scan(struct drm_gem_lru *lru,
 
 		dma_resv_unlock(obj->resv);
 
+		if (ticket)
+			ww_acquire_fini(ticket);
+
 tail:
 		drm_gem_object_put(obj);
 		mutex_lock(lru->lock);