[PATCH 1/9] Revert "drm/framebuffer: Acquire internal references on GEM handles"

[Thomas Zimmermann <tzimmermann@suse.de>]

This reverts commit f6bfc9afc7510cb5e6fbe0a17c507917b0120280.

Not needed as we are going to revert commit 5307dce878d4 ("drm/gem:
Acquire references on GEM handles for framebuffers").

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/drm_framebuffer.c            | 31 ++--------------
 drivers/gpu/drm/drm_gem.c                    | 38 ++++++++------------
 drivers/gpu/drm/drm_gem_framebuffer_helper.c | 16 +++++----
 drivers/gpu/drm/drm_internal.h               |  2 +-
 include/drm/drm_framebuffer.h                |  7 ----
 5 files changed, 26 insertions(+), 68 deletions(-)

diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
index 63a70f285cce..b781601946db 100644
--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -862,23 +862,11 @@ EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_framebuffer_free);
 int drm_framebuffer_init(struct drm_device *dev, struct drm_framebuffer *fb,
 			 const struct drm_framebuffer_funcs *funcs)
 {
-	unsigned int i;
 	int ret;
-	bool exists;
 
 	if (WARN_ON_ONCE(fb->dev != dev || !fb->format))
 		return -EINVAL;
 
-	for (i = 0; i < fb->format->num_planes; i++) {
-		if (drm_WARN_ON_ONCE(dev, fb->internal_flags & DRM_FRAMEBUFFER_HAS_HANDLE_REF(i)))
-			fb->internal_flags &= ~DRM_FRAMEBUFFER_HAS_HANDLE_REF(i);
-		if (fb->obj[i]) {
-			exists = drm_gem_object_handle_get_if_exists_unlocked(fb->obj[i]);
-			if (exists)
-				fb->internal_flags |= DRM_FRAMEBUFFER_HAS_HANDLE_REF(i);
-		}
-	}
-
 	INIT_LIST_HEAD(&fb->filp_head);
 
 	fb->funcs = funcs;
@@ -887,7 +875,7 @@ int drm_framebuffer_init(struct drm_device *dev, struct drm_framebuffer *fb,
 	ret = __drm_mode_object_add(dev, &fb->base, DRM_MODE_OBJECT_FB,
 				    false, drm_framebuffer_free);
 	if (ret)
-		goto err;
+		goto out;
 
 	mutex_lock(&dev->mode_config.fb_lock);
 	dev->mode_config.num_fb++;
@@ -895,16 +883,7 @@ int drm_framebuffer_init(struct drm_device *dev, struct drm_framebuffer *fb,
 	mutex_unlock(&dev->mode_config.fb_lock);
 
 	drm_mode_object_register(dev, &fb->base);
-
-	return 0;
-
-err:
-	for (i = 0; i < fb->format->num_planes; i++) {
-		if (fb->internal_flags & DRM_FRAMEBUFFER_HAS_HANDLE_REF(i)) {
-			drm_gem_object_handle_put_unlocked(fb->obj[i]);
-			fb->internal_flags &= ~DRM_FRAMEBUFFER_HAS_HANDLE_REF(i);
-		}
-	}
+out:
 	return ret;
 }
 EXPORT_SYMBOL(drm_framebuffer_init);
@@ -981,12 +960,6 @@ EXPORT_SYMBOL(drm_framebuffer_unregister_private);
 void drm_framebuffer_cleanup(struct drm_framebuffer *fb)
 {
 	struct drm_device *dev = fb->dev;
-	unsigned int i;
-
-	for (i = 0; i < fb->format->num_planes; i++) {
-		if (fb->internal_flags & DRM_FRAMEBUFFER_HAS_HANDLE_REF(i))
-			drm_gem_object_handle_put_unlocked(fb->obj[i]);
-	}
 
 	mutex_lock(&dev->mode_config.fb_lock);
 	list_del(&fb->head);
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 6a44351e58b7..3a99e4a5d303 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -224,34 +224,23 @@ static void drm_gem_object_handle_get(struct drm_gem_object *obj)
 }
 
 /**
- * drm_gem_object_handle_get_if_exists_unlocked - acquire reference on user-space handle, if any
+ * drm_gem_object_handle_get_unlocked - acquire reference on user-space handles
  * @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_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
+ * 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.
  */
-bool drm_gem_object_handle_get_if_exists_unlocked(struct drm_gem_object *obj)
+void drm_gem_object_handle_get_unlocked(struct drm_gem_object *obj)
 {
 	struct drm_device *dev = obj->dev;
 
 	guard(mutex)(&dev->object_name_lock);
 
-	/*
-	 * 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_WARN_ON(dev, !obj->handle_count); /* first ref taken in create-tail helper */
 	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
@@ -284,7 +273,7 @@ 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 handle
+ * drm_gem_object_handle_put_unlocked - releases reference on user-space handles
  * @obj: GEM object
  *
  * Releases a reference on the GEM buffer object's handle. Possibly releases
@@ -295,14 +284,14 @@ void drm_gem_object_handle_put_unlocked(struct drm_gem_object *obj)
 	struct drm_device *dev = obj->dev;
 	bool final = false;
 
-	if (drm_WARN_ON(dev, READ_ONCE(obj->handle_count) == 0))
+	if (WARN_ON(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) {
@@ -315,6 +304,7 @@ 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
diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
index 618ce725cd75..c60d0044d036 100644
--- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
+++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
@@ -100,7 +100,7 @@ void drm_gem_fb_destroy(struct drm_framebuffer *fb)
 	unsigned int i;
 
 	for (i = 0; i < fb->format->num_planes; i++)
-		drm_gem_object_put(fb->obj[i]);
+		drm_gem_object_handle_put_unlocked(fb->obj[i]);
 
 	drm_framebuffer_cleanup(fb);
 	kfree(fb);
@@ -183,8 +183,10 @@ int drm_gem_fb_init_with_funcs(struct drm_device *dev,
 		if (!objs[i]) {
 			drm_dbg_kms(dev, "Failed to lookup GEM object\n");
 			ret = -ENOENT;
-			goto err_gem_object_put;
+			goto err_gem_object_handle_put_unlocked;
 		}
+		drm_gem_object_handle_get_unlocked(objs[i]);
+		drm_gem_object_put(objs[i]);
 
 		min_size = (height - 1) * mode_cmd->pitches[i]
 			 + drm_format_info_min_pitch(info, i, width)
@@ -194,22 +196,22 @@ int drm_gem_fb_init_with_funcs(struct drm_device *dev,
 			drm_dbg_kms(dev,
 				    "GEM object size (%zu) smaller than minimum size (%u) for plane %d\n",
 				    objs[i]->size, min_size, i);
-			drm_gem_object_put(objs[i]);
+			drm_gem_object_handle_put_unlocked(objs[i]);
 			ret = -EINVAL;
-			goto err_gem_object_put;
+			goto err_gem_object_handle_put_unlocked;
 		}
 	}
 
 	ret = drm_gem_fb_init(dev, fb, mode_cmd, objs, i, funcs);
 	if (ret)
-		goto err_gem_object_put;
+		goto err_gem_object_handle_put_unlocked;
 
 	return 0;
 
-err_gem_object_put:
+err_gem_object_handle_put_unlocked:
 	while (i > 0) {
 		--i;
-		drm_gem_object_put(objs[i]);
+		drm_gem_object_handle_put_unlocked(objs[i]);
 	}
 	return ret;
 }
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index e79c3c623c9a..f921cc73f8b8 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -161,7 +161,7 @@ void drm_sysfs_lease_event(struct drm_device *dev);
 
 /* drm_gem.c */
 int drm_gem_init(struct drm_device *dev);
-bool drm_gem_object_handle_get_if_exists_unlocked(struct drm_gem_object *obj);
+void drm_gem_object_handle_get_unlocked(struct drm_gem_object *obj);
 void drm_gem_object_handle_put_unlocked(struct drm_gem_object *obj);
 int drm_gem_handle_create_tail(struct drm_file *file_priv,
 			       struct drm_gem_object *obj,
diff --git a/include/drm/drm_framebuffer.h b/include/drm/drm_framebuffer.h
index 38b24fc8978d..668077009fce 100644
--- a/include/drm/drm_framebuffer.h
+++ b/include/drm/drm_framebuffer.h
@@ -23,7 +23,6 @@
 #ifndef __DRM_FRAMEBUFFER_H__
 #define __DRM_FRAMEBUFFER_H__
 
-#include <linux/bits.h>
 #include <linux/ctype.h>
 #include <linux/list.h>
 #include <linux/sched.h>
@@ -101,8 +100,6 @@ struct drm_framebuffer_funcs {
 		     unsigned num_clips);
 };
 
-#define DRM_FRAMEBUFFER_HAS_HANDLE_REF(_i)	BIT(0u + (_i))
-
 /**
  * struct drm_framebuffer - frame buffer object
  *
@@ -191,10 +188,6 @@ struct drm_framebuffer {
 	 * DRM_MODE_FB_MODIFIERS.
 	 */
 	int flags;
-	/**
-	 * @internal_flags: Framebuffer flags like DRM_FRAMEBUFFER_HAS_HANDLE_REF.
-	 */
-	unsigned int internal_flags;
 	/**
 	 * @filp_head: Placed on &drm_file.fbs, protected by &drm_file.fbs_lock.
 	 */
-- 
2.50.0