From 6bcacf51d050d412e5c302e0dd5e582212c5f7be Mon Sep 17 00:00:00 2001 From: Daniel Stone Date: Mon, 20 Apr 2015 19:22:55 +0100 Subject: [PATCH] drm: Add reference counting to blob properties Reference-count drm_property_blob objects, changing the API to ref/unref. Signed-off-by: Daniel Stone Reviewed-by: Maarten Lankhorst [danvet: Squash in kerneldoc fixup from Daniel Stone.] [danvet: Squash in Oops fix from Thiery Reding.] Signed-off-by: Daniel Vetter --- drivers/gpu/drm/drm_crtc.c | 163 +++++++++++++++++++++++++++++++++---- include/drm/drm_crtc.h | 17 ++-- 2 files changed, 158 insertions(+), 22 deletions(-) diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index 3b6573527e7f..2e26988a9762 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -352,7 +352,9 @@ static struct drm_mode_object *_object_find(struct drm_device *dev, if (obj && obj->id != id) obj = NULL; /* don't leak out unref'd fb's */ - if (obj && (obj->type == DRM_MODE_OBJECT_FB)) + if (obj && + (obj->type == DRM_MODE_OBJECT_FB || + obj->type == DRM_MODE_OBJECT_BLOB)) obj = NULL; mutex_unlock(&dev->mode_config.idr_mutex); @@ -377,7 +379,7 @@ struct drm_mode_object *drm_mode_object_find(struct drm_device *dev, /* Framebuffers are reference counted and need their own lookup * function.*/ - WARN_ON(type == DRM_MODE_OBJECT_FB); + WARN_ON(type == DRM_MODE_OBJECT_FB || type == DRM_MODE_OBJECT_BLOB); obj = _object_find(dev, id, type); return obj; } @@ -4202,7 +4204,7 @@ done: return ret; } -static struct drm_property_blob * +struct drm_property_blob * drm_property_create_blob(struct drm_device *dev, size_t length, const void *data) { @@ -4217,6 +4219,7 @@ drm_property_create_blob(struct drm_device *dev, size_t length, return NULL; blob->length = length; + blob->dev = dev; memcpy(blob->data, data, length); @@ -4229,24 +4232,146 @@ drm_property_create_blob(struct drm_device *dev, size_t length, return NULL; } + kref_init(&blob->refcount); + list_add_tail(&blob->head, &dev->mode_config.property_blob_list); mutex_unlock(&dev->mode_config.blob_lock); return blob; } +EXPORT_SYMBOL(drm_property_create_blob); -static void drm_property_destroy_blob(struct drm_device *dev, - struct drm_property_blob *blob) +/** + * drm_property_free_blob - Blob property destructor + * + * Internal free function for blob properties; must not be used directly. + * + * @param kref Reference + */ +static void drm_property_free_blob(struct kref *kref) { - mutex_lock(&dev->mode_config.blob_lock); - drm_mode_object_put(dev, &blob->base); + struct drm_property_blob *blob = + container_of(kref, struct drm_property_blob, refcount); + + WARN_ON(!mutex_is_locked(&blob->dev->mode_config.blob_lock)); + list_del(&blob->head); - mutex_unlock(&dev->mode_config.blob_lock); + drm_mode_object_put(blob->dev, &blob->base); kfree(blob); } +/** + * drm_property_unreference_blob - Unreference a blob property + * + * Drop a reference on a blob property. May free the object. + * + * @param blob Pointer to blob property + */ +void drm_property_unreference_blob(struct drm_property_blob *blob) +{ + struct drm_device *dev; + + if (!blob) + return; + + dev = blob->dev; + + DRM_DEBUG("%p: blob ID: %d (%d)\n", blob, blob->base.id, atomic_read(&blob->refcount.refcount)); + + if (kref_put_mutex(&blob->refcount, drm_property_free_blob, + &dev->mode_config.blob_lock)) + mutex_unlock(&dev->mode_config.blob_lock); + else + might_lock(&dev->mode_config.blob_lock); + +} +EXPORT_SYMBOL(drm_property_unreference_blob); + +/** + * drm_property_unreference_blob_locked - Unreference a blob property with blob_lock held + * + * Drop a reference on a blob property. May free the object. This must be + * called with blob_lock held. + * + * @param dev Device the blob was created on + * @param blob Pointer to blob property + */ +static void drm_property_unreference_blob_locked(struct drm_property_blob *blob) +{ + if (!blob) + return; + + DRM_DEBUG("%p: blob ID: %d (%d)\n", blob, blob->base.id, atomic_read(&blob->refcount.refcount)); + + kref_put(&blob->refcount, drm_property_free_blob); +} + +/** + * drm_property_reference_blob - Take a reference on an existing property + * + * Take a new reference on an existing blob property. + * + * @param blob Pointer to blob property + */ +struct drm_property_blob *drm_property_reference_blob(struct drm_property_blob *blob) +{ + DRM_DEBUG("%p: blob ID: %d (%d)\n", blob, blob->base.id, atomic_read(&blob->refcount.refcount)); + kref_get(&blob->refcount); + return blob; +} +EXPORT_SYMBOL(drm_property_reference_blob); + +/* + * Like drm_property_lookup_blob, but does not return an additional reference. + * Must be called with blob_lock held. + */ +static struct drm_property_blob *__drm_property_lookup_blob(struct drm_device *dev, + uint32_t id) +{ + struct drm_mode_object *obj = NULL; + struct drm_property_blob *blob; + + WARN_ON(!mutex_is_locked(&dev->mode_config.blob_lock)); + + mutex_lock(&dev->mode_config.idr_mutex); + obj = idr_find(&dev->mode_config.crtc_idr, id); + if (!obj || (obj->type != DRM_MODE_OBJECT_BLOB) || (obj->id != id)) + blob = NULL; + else + blob = obj_to_blob(obj); + mutex_unlock(&dev->mode_config.idr_mutex); + + return blob; +} + +/** + * drm_property_lookup_blob - look up a blob property and take a reference + * @dev: drm device + * @id: id of the blob property + * + * If successful, this takes an additional reference to the blob property. + * callers need to make sure to eventually unreference the returned property + * again, using @drm_property_unreference_blob. + */ +struct drm_property_blob *drm_property_lookup_blob(struct drm_device *dev, + uint32_t id) +{ + struct drm_property_blob *blob; + + mutex_lock(&dev->mode_config.blob_lock); + blob = __drm_property_lookup_blob(dev, id); + if (blob) { + if (!kref_get_unless_zero(&blob->refcount)) + blob = NULL; + } + mutex_unlock(&dev->mode_config.blob_lock); + + return blob; +} +EXPORT_SYMBOL(drm_property_lookup_blob); + /** * drm_property_replace_global_blob - atomically replace existing blob property * @dev: drm device @@ -4313,14 +4438,14 @@ static int drm_property_replace_global_blob(struct drm_device *dev, } if (old_blob) - drm_property_destroy_blob(dev, old_blob); + drm_property_unreference_blob(old_blob); *replace = new_blob; return 0; err_created: - drm_property_destroy_blob(dev, new_blob); + drm_property_unreference_blob(new_blob); return ret; } @@ -4351,7 +4476,7 @@ int drm_mode_getblob_ioctl(struct drm_device *dev, drm_modeset_lock_all(dev); mutex_lock(&dev->mode_config.blob_lock); - blob = drm_property_blob_find(dev, out_resp->blob_id); + blob = __drm_property_lookup_blob(dev, out_resp->blob_id); if (!blob) { ret = -ENOENT; goto done; @@ -4515,8 +4640,18 @@ bool drm_property_change_valid_get(struct drm_property *property, valid_mask |= (1ULL << property->values[i]); return !(value & ~valid_mask); } else if (drm_property_type_is(property, DRM_MODE_PROP_BLOB)) { - /* Only the driver knows */ - return true; + struct drm_property_blob *blob; + + if (value == 0) + return true; + + blob = drm_property_lookup_blob(property->dev, value); + if (blob) { + *ref = &blob->base; + return true; + } else { + return false; + } } else if (drm_property_type_is(property, DRM_MODE_PROP_OBJECT)) { /* a zero value for an object property translates to null: */ if (value == 0) @@ -5566,7 +5701,7 @@ void drm_mode_config_cleanup(struct drm_device *dev) list_for_each_entry_safe(blob, bt, &dev->mode_config.property_blob_list, head) { - drm_property_destroy_blob(dev, blob); + drm_property_unreference_blob(blob); } /* diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index 55ed8f9f45be..5626191f3af0 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -216,6 +216,8 @@ struct drm_framebuffer { struct drm_property_blob { struct drm_mode_object base; + struct drm_device *dev; + struct kref refcount; struct list_head head; size_t length; unsigned char data[]; @@ -1365,6 +1367,13 @@ struct drm_property *drm_property_create_object(struct drm_device *dev, int flags, const char *name, uint32_t type); struct drm_property *drm_property_create_bool(struct drm_device *dev, int flags, const char *name); +struct drm_property_blob *drm_property_create_blob(struct drm_device *dev, + size_t length, + const void *data); +struct drm_property_blob *drm_property_lookup_blob(struct drm_device *dev, + uint32_t id); +struct drm_property_blob *drm_property_reference_blob(struct drm_property_blob *blob); +void drm_property_unreference_blob(struct drm_property_blob *blob); extern void drm_property_destroy(struct drm_device *dev, struct drm_property *property); extern int drm_property_add_enum(struct drm_property *property, int index, uint64_t value, const char *name); @@ -1528,14 +1537,6 @@ static inline struct drm_property *drm_property_find(struct drm_device *dev, return mo ? obj_to_property(mo) : NULL; } -static inline struct drm_property_blob * -drm_property_blob_find(struct drm_device *dev, uint32_t id) -{ - struct drm_mode_object *mo; - mo = drm_mode_object_find(dev, id, DRM_MODE_OBJECT_BLOB); - return mo ? obj_to_blob(mo) : NULL; -} - /* Plane list iterator for legacy (overlay only) planes. */ #define drm_for_each_legacy_plane(plane, planelist) \ list_for_each_entry(plane, planelist, head) \ -- 2.20.1