Restore pre-idr semantics for drawable information.

There's a difference between a drawable ID not having valid drawable
information and not being allocated at all. Not making the distinction would
break i915 DRM swap scheduling with older X servers that don't push drawable
cliprect information to the DRM.

1 files changed, 25 insertions, 18 deletions

diff --git a/linux-core/drm_drawable.c b/linux-core/drm_drawable.c
index 74f0bb5d..7657e954 100644
--- a/linux-core/drm_drawable.c
+++ b/linux-core/drm_drawable.c
@@ -37,6 +37,8 @@
 
 #include "drmP.h"
 
+#define NO_DRW_INFO (void*)1
+
 /**
  * Allocate drawable ID and memory to store information about it.
  */
@@ -44,24 +46,18 @@ int drm_adddraw(DRM_IOCTL_ARGS)
 {
 	DRM_DEVICE;
 	unsigned long irqflags;
-	struct drm_drawable_info *draw_info;
 	drm_draw_t draw;
 	int new_id = 0;
 	int ret;
 
-	draw_info = drm_calloc(1, sizeof(*draw_info), DRM_MEM_BUFS);
-	if (!draw_info)
-		return -ENOMEM;
-
 again:
 	if (idr_pre_get(&dev->drw_idr, GFP_KERNEL) == 0) {
 		DRM_ERROR("Out of memory expanding drawable idr\n");
-		drm_free(draw_info, sizeof(struct drm_drawable_info), DRM_MEM_BUFS);
 		return -ENOMEM;
 	}
 
 	spin_lock_irqsave(&dev->drw_lock, irqflags);
-	ret = idr_get_new_above(&dev->drw_idr, draw_info, 1, &new_id);
+	ret = idr_get_new_above(&dev->drw_idr, NO_DRW_INFO, 1, &new_id);
 	if (ret == -EAGAIN) {
 		spin_unlock_irqrestore(&dev->drw_lock, irqflags);
 		goto again;
@@ -86,21 +82,16 @@ int drm_rmdraw(DRM_IOCTL_ARGS)
 	DRM_DEVICE;
 	drm_draw_t draw;
 	unsigned long irqflags;
-	struct drm_drawable_info *draw_info;
 
 	DRM_COPY_FROM_USER_IOCTL(draw, (drm_draw_t __user *) data,
 				 sizeof(draw));
 
-	draw_info = idr_find(&dev->drw_idr, draw.handle);
-	if (!draw_info) {
-		DRM_DEBUG("No such drawable %d\n", draw.handle);
-		return -EINVAL;
-	}
-
 	spin_lock_irqsave(&dev->drw_lock, irqflags);
 
+	drm_free(drm_get_drawable_info(dev, draw.handle),
+		 sizeof(struct drm_drawable_info), DRM_MEM_BUFS);
+
 	idr_remove(&dev->drw_idr, draw.handle);
-	drm_free(draw_info, sizeof(struct drm_drawable_info), DRM_MEM_BUFS);
 
 	spin_unlock_irqrestore(&dev->drw_lock, irqflags);
 	DRM_DEBUG("%d\n", draw.handle);
@@ -125,6 +116,13 @@ int drm_update_drawable_info(DRM_IOCTL_ARGS)
 		return DRM_ERR(EINVAL);
 	}
 
+	if (info == NO_DRW_INFO) {
+		info = drm_calloc(1, sizeof(*info), DRM_MEM_BUFS);
+		if (!info)
+			return -ENOMEM;
+		idr_replace(&dev->drw_idr, info, update.handle);
+	}
+
 	switch (update.type) {
 	case DRM_DRAWABLE_CLIPRECTS:
 		if (update.num != info->num_rects) {
@@ -187,11 +185,17 @@ drm_drawable_info_t *drm_get_drawable_info(drm_device_t *dev, drm_drawable_t id)
 	struct drm_drawable_info *info;
 
 	info = idr_find(&dev->drw_idr, id);
+
 	if (!info) {
 		DRM_DEBUG("No such drawable %d\n", id);
 		return NULL;
 	}
 
+	if (info == NO_DRW_INFO) {
+		DRM_DEBUG("No information for drawable %d\n", id);
+		return NULL;
+	}
+
 	return info;
 }
 EXPORT_SYMBOL(drm_get_drawable_info);
@@ -200,9 +204,12 @@ static int drm_drawable_free(int idr, void *p, void *data)
 {
 	struct drm_drawable_info *info = p;
 
-	drm_free(info->rects, info->num_rects *
-		 sizeof(drm_clip_rect_t), DRM_MEM_BUFS);
-	drm_free(info, sizeof(struct drm_drawable_info), DRM_MEM_BUFS);
+	if (info != NO_DRW_INFO) {
+		drm_free(info->rects, info->num_rects *
+			 sizeof(drm_clip_rect_t), DRM_MEM_BUFS);
+		drm_free(info, sizeof(*info), DRM_MEM_BUFS);
+	}
+
 	return 0;
 }