drm/gem: handlecount isn't really a kref so don't make it one.

There were lots of places being inconsistent since handle count
looked like a kref but it really wasn't.

Fix this my just making handle count an atomic on the object,
and have it increase the normal object kref.

Now i915/radeon/nouveau drivers can drop the normal reference on
userspace object creation, and have the handle hold it.

This patch fixes a memory leak or corruption on unload, because
the driver had no way of knowing if a handle had been actually
added for this object, and the fbcon object needed to know this
to clean itself up properly.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>

3 files changed, 8 insertions, 13 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index 7422f274615a..b92d2f2fcbed 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -843,8 +843,9 @@ static void radeon_user_framebuffer_destroy(struct drm_framebuffer *fb)
 {
         struct radeon_framebuffer *radeon_fb = to_radeon_framebuffer(fb);
 
-        if (radeon_fb->obj)
+        if (radeon_fb->obj) {
                 drm_gem_object_unreference_unlocked(radeon_fb->obj);
+        }
         drm_framebuffer_cleanup(fb);
         kfree(radeon_fb);
 }
diff --git a/drivers/gpu/drm/radeon/radeon_fb.c b/drivers/gpu/drm/radeon/radeon_fb.c
index c74a8b20d941..9cdf6a35bc2c 100644
--- a/drivers/gpu/drm/radeon/radeon_fb.c
+++ b/drivers/gpu/drm/radeon/radeon_fb.c
@@ -94,8 +94,10 @@ static void radeonfb_destroy_pinned_object(struct drm_gem_object *gobj)
         ret = radeon_bo_reserve(rbo, false);
         if (likely(ret == 0)) {
                 radeon_bo_kunmap(rbo);
+                radeon_bo_unpin(rbo);
                 radeon_bo_unreserve(rbo);
         }
+        drm_gem_object_handle_unreference(gobj);
         drm_gem_object_unreference_unlocked(gobj);
 }
 
@@ -325,8 +327,6 @@ static int radeon_fbdev_destroy(struct drm_device *dev, struct radeon_fbdev *rfb
 {
         struct fb_info *info;
         struct radeon_framebuffer *rfb = &rfbdev->rfb;
-        struct radeon_bo *rbo;
-        int r;
 
         if (rfbdev->helper.fbdev) {
                 info = rfbdev->helper.fbdev;
@@ -338,14 +338,8 @@ static int radeon_fbdev_destroy(struct drm_device *dev, struct radeon_fbdev *rfb
         }
 
         if (rfb->obj) {
-                rbo = rfb->obj->driver_private;
-                r = radeon_bo_reserve(rbo, false);
-                if (likely(r == 0)) {
-                        radeon_bo_kunmap(rbo);
-                        radeon_bo_unpin(rbo);
-                        radeon_bo_unreserve(rbo);
-                }
-                drm_gem_object_unreference_unlocked(rfb->obj);
+                radeonfb_destroy_pinned_object(rfb->obj);
+                rfb->obj = NULL;
         }
         drm_fb_helper_fini(&rfbdev->helper);
         drm_framebuffer_cleanup(&rfb->base);
diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c
index c578f265b24c..d1e595d91723 100644
--- a/drivers/gpu/drm/radeon/radeon_gem.c
+++ b/drivers/gpu/drm/radeon/radeon_gem.c
@@ -201,11 +201,11 @@ int radeon_gem_create_ioctl(struct drm_device *dev, void *data,
                 return r;
         }
         r = drm_gem_handle_create(filp, gobj, &handle);
+        /* drop reference from allocate - handle holds it now */
+        drm_gem_object_unreference_unlocked(gobj);
         if (r) {
-                drm_gem_object_unreference_unlocked(gobj);
                 return r;
         }
-        drm_gem_object_handle_unreference_unlocked(gobj);
         args->handle = handle;
         return 0;
 }