[PATCH 22/51] drm: manage drm_minor cleanup with drmm_

[Daniel Vetter]

The cleanup here is somewhat tricky, since we can't tell apart the
allocated minor index from 0. So register a cleanup action first, and
if the index allocation fails, unregister that cleanup action again to
avoid bad mistakes.

The kdev for the minor already handles NULL, so no problem there.

Hence add drmm_remove_action() to the drm_managed library.

v2: Make pointer math around void ** consistent with what Laurent
suggested.

Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/drm_drv.c     | 74 +++++++++++++----------------------
 drivers/gpu/drm/drm_managed.c | 28 +++++++++++++
 include/drm/drm_managed.h     |  4 ++
 3 files changed, 59 insertions(+), 47 deletions(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 1f7ab88d9435..03a1fb377830 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -93,19 +93,35 @@ static struct drm_minor **drm_minor_get_slot(struct drm_device *dev,
 	}
 }
 
+static void drm_minor_alloc_release(struct drm_device *dev, void *data)
+{
+	struct drm_minor *minor = data;
+	unsigned long flags;
+
+	put_device(minor->kdev);
+
+	spin_lock_irqsave(&drm_minor_lock, flags);
+	idr_remove(&drm_minors_idr, minor->index);
+	spin_unlock_irqrestore(&drm_minor_lock, flags);
+}
+
 static int drm_minor_alloc(struct drm_device *dev, unsigned int type)
 {
 	struct drm_minor *minor;
 	unsigned long flags;
 	int r;
 
-	minor = kzalloc(sizeof(*minor), GFP_KERNEL);
+	minor = drmm_kzalloc(dev, sizeof(*minor), GFP_KERNEL);
 	if (!minor)
 		return -ENOMEM;
 
 	minor->type = type;
 	minor->dev = dev;
 
+	r = drmm_add_action(dev, drm_minor_alloc_release, minor);
+	if (r)
+		return r;
+
 	idr_preload(GFP_KERNEL);
 	spin_lock_irqsave(&drm_minor_lock, flags);
 	r = idr_alloc(&drm_minors_idr,
@@ -116,47 +132,18 @@ static int drm_minor_alloc(struct drm_device *dev, unsigned int type)
 	spin_unlock_irqrestore(&drm_minor_lock, flags);
 	idr_preload_end();
 
-	if (r < 0)
-		goto err_free;
+	if (r < 0) {
+		drmm_remove_action(dev, drm_minor_alloc_release, minor);
+		return r;
+	}
 
 	minor->index = r;
-
 	minor->kdev = drm_sysfs_minor_alloc(minor);
-	if (IS_ERR(minor->kdev)) {
-		r = PTR_ERR(minor->kdev);
-		goto err_index;
-	}
+	if (IS_ERR(minor->kdev))
+		return PTR_ERR(minor->kdev);
 
 	*drm_minor_get_slot(dev, type) = minor;
 	return 0;
-
-err_index:
-	spin_lock_irqsave(&drm_minor_lock, flags);
-	idr_remove(&drm_minors_idr, minor->index);
-	spin_unlock_irqrestore(&drm_minor_lock, flags);
-err_free:
-	kfree(minor);
-	return r;
-}
-
-static void drm_minor_free(struct drm_device *dev, unsigned int type)
-{
-	struct drm_minor **slot, *minor;
-	unsigned long flags;
-
-	slot = drm_minor_get_slot(dev, type);
-	minor = *slot;
-	if (!minor)
-		return;
-
-	put_device(minor->kdev);
-
-	spin_lock_irqsave(&drm_minor_lock, flags);
-	idr_remove(&drm_minors_idr, minor->index);
-	spin_unlock_irqrestore(&drm_minor_lock, flags);
-
-	kfree(minor);
-	*slot = NULL;
 }
 
 static int drm_minor_register(struct drm_device *dev, unsigned int type)
@@ -678,16 +665,16 @@ int drm_dev_init(struct drm_device *dev,
 	if (drm_core_check_feature(dev, DRIVER_RENDER)) {
 		ret = drm_minor_alloc(dev, DRM_MINOR_RENDER);
 		if (ret)
-			goto err_minors;
+			goto err;
 	}
 
 	ret = drm_minor_alloc(dev, DRM_MINOR_PRIMARY);
 	if (ret)
-		goto err_minors;
+		goto err;
 
 	ret = drm_legacy_create_map_hash(dev);
 	if (ret)
-		goto err_minors;
+		goto err;
 
 	drm_legacy_ctxbitmap_init(dev);
 
@@ -695,7 +682,7 @@ int drm_dev_init(struct drm_device *dev,
 		ret = drm_gem_init(dev);
 		if (ret) {
 			DRM_ERROR("Cannot initialize graphics execution manager (GEM)\n");
-			goto err_ctxbitmap;
+			goto err;
 		}
 	}
 
@@ -708,10 +695,6 @@ int drm_dev_init(struct drm_device *dev,
 err_setunique:
 	if (drm_core_check_feature(dev, DRIVER_GEM))
 		drm_gem_destroy(dev);
-err_ctxbitmap:
-err_minors:
-	drm_minor_free(dev, DRM_MINOR_PRIMARY);
-	drm_minor_free(dev, DRM_MINOR_RENDER);
 err:
 	drm_managed_release(dev);
 
@@ -776,9 +759,6 @@ void drm_dev_fini(struct drm_device *dev)
 
 	if (drm_core_check_feature(dev, DRIVER_GEM))
 		drm_gem_destroy(dev);
-
-	drm_minor_free(dev, DRM_MINOR_PRIMARY);
-	drm_minor_free(dev, DRM_MINOR_RENDER);
 }
 EXPORT_SYMBOL(drm_dev_fini);
 
diff --git a/drivers/gpu/drm/drm_managed.c b/drivers/gpu/drm/drm_managed.c
index cc917187a723..626656369f0b 100644
--- a/drivers/gpu/drm/drm_managed.c
+++ b/drivers/gpu/drm/drm_managed.c
@@ -134,6 +134,34 @@ int __drmm_add_action(struct drm_device *dev,
 }
 EXPORT_SYMBOL(__drmm_add_action);
 
+void drmm_remove_action(struct drm_device *dev,
+			drmres_release_t action,
+			void *data)
+{
+	struct drmres *dr = NULL, *tmp;
+	unsigned long flags;
+
+	if (!data)
+		return;
+
+	spin_lock_irqsave(&dev->managed.lock, flags);
+	list_for_each_entry(tmp, &dev->managed.resources, node.entry) {
+		if (tmp->node.release == action &&
+		    *(void **)&tmp->data == data) {
+			dr = tmp;
+			del_dr(dev, dr);
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&dev->managed.lock, flags);
+
+	if (WARN_ON(!dr))
+		return;
+
+	kfree(dr);
+}
+EXPORT_SYMBOL(drmm_remove_action);
+
 void *drmm_kmalloc(struct drm_device *dev, size_t size, gfp_t gfp)
 {
 	struct drmres *dr;
diff --git a/include/drm/drm_managed.h b/include/drm/drm_managed.h
index 89e6fce9f689..5280209dff92 100644
--- a/include/drm/drm_managed.h
+++ b/include/drm/drm_managed.h
@@ -17,6 +17,10 @@ int __must_check __drmm_add_action(struct drm_device *dev,
 				   drmres_release_t action,
 				   void *data, const char *name);
 
+void drmm_remove_action(struct drm_device *dev,
+			drmres_release_t action,
+			void *data);
+
 void drmm_add_final_kfree(struct drm_device *dev, void *parent);
 
 void *drmm_kmalloc(struct drm_device *dev, size_t size, gfp_t gfp) __malloc;
-- 
2.24.1