From: Keith Packard <keithp@keithp.com>
Date: Fri, 2 May 2008 03:12:39 +0000 (-0700)
Subject: Use krefs for refcounting.
X-Git-Tag: android-x86-1.6~256^2~168
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=abc896638fdcd8ccb457ad7b43dbe7ad229ba501;p=android-x86%2Fexternal-libdrm.git

Use krefs for refcounting.

krefs are way easier than a custom-coded spinlock+int combo.
---

diff --git a/linux-core/drmP.h b/linux-core/drmP.h
index 2ed17b81..0df9f19b 100644
--- a/linux-core/drmP.h
+++ b/linux-core/drmP.h
@@ -54,6 +54,7 @@
 #include <linux/smp_lock.h>	/* For (un)lock_kernel */
 #include <linux/dma-mapping.h>
 #include <linux/mm.h>
+#include <linux/kref.h>
 #include <linux/pagemap.h>
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
 #include <linux/mutex.h>
@@ -614,20 +615,21 @@ struct drm_ati_pcigart_info {
  * DRM for its buffer objects.
  */
 struct drm_gem_object {
+	/** Reference count of this object */
+	struct kref refcount;
+
+	/** Related drm device */
+	struct drm_device *dev;
+	
 	/** File representing the shmem storage */
 	struct file *filp;
 
-	spinlock_t lock;
-
 	/**
 	 * Size of the object, in bytes.  Immutable over the object's
 	 * lifetime.
 	 */
 	size_t size;
 
-	/** Reference count of this object, protected by object_lock */
-	int refcount;
-
 	void *driver_private;
 };
 
diff --git a/linux-core/drm_gem.c b/linux-core/drm_gem.c
index ee3dbe47..d39585e9 100644
--- a/linux-core/drm_gem.c
+++ b/linux-core/drm_gem.c
@@ -73,13 +73,14 @@ drm_gem_object_alloc(struct drm_device *dev, size_t size)
 
 	obj = kcalloc(1, sizeof(*obj), GFP_KERNEL);
 
+	obj->dev = dev;
 	obj->filp = shmem_file_setup("drm mm object", size, 0);
 	if (IS_ERR(obj->filp)) {
 		kfree(obj);
 		return NULL;
 	}
 
-	obj->refcount = 1;
+	kref_init (&obj->refcount);
 	obj->size = size;
 
 	if (dev->driver->gem_init_object != NULL &&
@@ -352,27 +353,29 @@ drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
 void
 drm_gem_object_reference(struct drm_device *dev, struct drm_gem_object *obj)
 {
-	spin_lock(&obj->lock);
-	obj->refcount++;
-	spin_unlock(&obj->lock);
+	kref_get(&obj->refcount);
 }
 EXPORT_SYMBOL(drm_gem_object_reference);
 
+static void
+drm_gem_object_free (struct kref *kref)
+{
+	struct drm_gem_object *obj = (struct drm_gem_object *) kref;
+	struct drm_device *dev = obj->dev;
+
+	if (dev->driver->gem_free_object != NULL)
+		dev->driver->gem_free_object(dev, obj);
+
+	fput(obj->filp);
+	kfree(obj);
+}
+
 void
 drm_gem_object_unreference(struct drm_device *dev, struct drm_gem_object *obj)
 {
 	if (obj == NULL)
 		return;
 
-	spin_lock(&obj->lock);
-	obj->refcount--;
-	spin_unlock(&obj->lock);
-	if (obj->refcount == 0) {
-		if (dev->driver->gem_free_object != NULL)
-			dev->driver->gem_free_object(dev, obj);
-
-		fput(obj->filp);
-		kfree(obj);
-	}
+	kref_put (&obj->refcount, drm_gem_object_free);
 }
 EXPORT_SYMBOL(drm_gem_object_unreference);