[PATCH 1/2] drm/prime: split drm_gem_prime_fd_to_handle()

[Emil Velikov]

From: Emil Velikov <emil.velikov at collabora.com>

Currently drm_gem_prime_fd_to_handle() consists of illegible amount of
goto labels, for no obvious reason.

Split it in two (as below) making the code far simpler and obvious.

drm_gem_prime_fd_to_handle()
- prime mtx handling
- fd/dmabuf refcounting
- hash table lookup

import_buf_to_handle()
 - drm_gem_object import and locking
 - creating a handle for the gem object
 - adding the handle/fd to the hash table

Cc: Daniel Vetter <daniel at ffwll.ch>
Signed-off-by: Emil Velikov <emil.velikov at collabora.com>
---
 drivers/gpu/drm/drm_prime.c | 86 ++++++++++++++++++-------------------
 1 file changed, 41 insertions(+), 45 deletions(-)

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index dc079efb3b0f..0d83b9bbf793 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -777,37 +777,14 @@ struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_gem_prime_import);
 
-/**
- * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
- * @dev: dev to export the buffer from
- * @file_priv: drm file-private structure
- * @prime_fd: fd id of the dma-buf which should be imported
- * @handle: pointer to storage for the handle of the imported buffer object
- *
- * This is the PRIME import function which must be used mandatorily by GEM
- * drivers to ensure correct lifetime management of the underlying GEM object.
- * The actual importing of GEM object from the dma-buf is done through the
- * gem_import_export driver callback.
- */
-int drm_gem_prime_fd_to_handle(struct drm_device *dev,
-			       struct drm_file *file_priv, int prime_fd,
-			       uint32_t *handle)
+static int import_buf_to_handle(struct drm_device *dev,
+			        struct drm_file *file_priv,
+			        struct dma_buf *dma_buf,
+			        uint32_t *handle)
 {
-	struct dma_buf *dma_buf;
 	struct drm_gem_object *obj;
 	int ret;
 
-	dma_buf = dma_buf_get(prime_fd);
-	if (IS_ERR(dma_buf))
-		return PTR_ERR(dma_buf);
-
-	mutex_lock(&file_priv->prime.lock);
-
-	ret = drm_prime_lookup_buf_handle(&file_priv->prime,
-			dma_buf, handle);
-	if (ret == 0)
-		goto out_put;
-
 	/* never seen this one, need to import */
 	mutex_lock(&dev->object_name_lock);
 	if (dev->driver->gem_prime_import)
@@ -816,7 +793,8 @@ int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 		obj = drm_gem_prime_import(dev, dma_buf);
 	if (IS_ERR(obj)) {
 		ret = PTR_ERR(obj);
-		goto out_unlock;
+		mutex_unlock(&dev->object_name_lock);
+		return ret;
 	}
 
 	if (obj->dma_buf) {
@@ -830,29 +808,47 @@ int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 	ret = drm_gem_handle_create_tail(file_priv, obj, handle);
 	drm_gem_object_put_unlocked(obj);
 	if (ret)
-		goto out_put;
+		return ret;
 
-	ret = drm_prime_add_buf_handle(&file_priv->prime,
-			dma_buf, *handle);
-	mutex_unlock(&file_priv->prime.lock);
+	ret = drm_prime_add_buf_handle(&file_priv->prime, dma_buf, *handle);
 	if (ret)
-		goto fail;
+		/* hmm, if driver attached, we are relying on the free-object
+		 * path to detach.. which seems ok..
+		 */
+		drm_gem_handle_delete(file_priv, *handle);
 
-	dma_buf_put(dma_buf);
+	return ret;
+}
 
-	return 0;
+/**
+ * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
+ * @dev: dev to export the buffer from
+ * @file_priv: drm file-private structure
+ * @prime_fd: fd id of the dma-buf which should be imported
+ * @handle: pointer to storage for the handle of the imported buffer object
+ *
+ * This is the PRIME import function which must be used mandatorily by GEM
+ * drivers to ensure correct lifetime management of the underlying GEM object.
+ * The actual importing of GEM object from the dma-buf is done through the
+ * gem_import_export driver callback.
+ */
+int drm_gem_prime_fd_to_handle(struct drm_device *dev,
+			       struct drm_file *file_priv, int prime_fd,
+			       uint32_t *handle)
+{
+	struct dma_buf *dma_buf;
+	int ret;
 
-fail:
-	/* hmm, if driver attached, we are relying on the free-object path
-	 * to detach.. which seems ok..
-	 */
-	drm_gem_handle_delete(file_priv, *handle);
-	dma_buf_put(dma_buf);
-	return ret;
+	dma_buf = dma_buf_get(prime_fd);
+	if (IS_ERR(dma_buf))
+		return PTR_ERR(dma_buf);
+
+	mutex_lock(&file_priv->prime.lock);
+
+	ret = drm_prime_lookup_buf_handle(&file_priv->prime, dma_buf, handle);
+	if (ret)
+		ret = import_buf_to_handle(dev, file_priv, dma_buf, handle);
 
-out_unlock:
-	mutex_unlock(&dev->object_name_lock);
-out_put:
 	mutex_unlock(&file_priv->prime.lock);
 	dma_buf_put(dma_buf);
 	return ret;
-- 
2.21.0