[PATCH 4.6 128/203] drm: Wrap direct calls to driver->gem_free_object from CMA

From: Greg Kroah-Hartman
Date: Mon Jul 25 2016 - 18:12:04 EST

4.6-stable review patch. If anyone has any objections, please let me know.


From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>

commit afe705be38f1e65b173868486944377186b9f206 upstream.

Since the introduction of (struct_mutex) lockless GEM bo freeing, there
are a pair of driver vfuncs for freeing the GEM bo, of which the driver
may choose to only implement driver->gem_object_free_unlocked (and so
avoid taking the struct_mutex along the free path). However, the CMA GEM
helpers were still calling driver->gem_free_object directly, now NULL,
and promptly dying on the fancy new lockless drivers. Oops.

Robert Foss bisected this to b82caafcf2303 (drm/vc4: Use lockless gem BO
free callback) on his vc4 device, but that just serves as an enabler for
9f0ba539d13ae (drm/gem: support BO freeing without dev->struct_mutex).

Reported-by: Robert Foss <robert.foss@xxxxxxxxxxxxx>
Fixes: 9f0ba539d13ae (drm/gem: support BO freeing without dev->struct_mutex)
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Robert Foss <robert.foss@xxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: Eric Anholt <eric@xxxxxxxxxx>
Cc: Alex Deucher <alexdeucher@xxxxxxxxx>
Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Tested-by: Robert Foss <robert.foss@xxxxxxxxxxxxx>
Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/gpu/drm/drm_fb_cma_helper.c | 2 +-
drivers/gpu/drm/drm_gem_cma_helper.c | 12 +++---------
2 files changed, 4 insertions(+), 10 deletions(-)

--- a/drivers/gpu/drm/drm_fb_cma_helper.c
+++ b/drivers/gpu/drm/drm_fb_cma_helper.c
@@ -301,7 +301,7 @@ static int drm_fbdev_cma_create(struct d
- dev->driver->gem_free_object(&obj->base);
+ drm_gem_object_unreference_unlocked(&obj->base);
return ret;

--- a/drivers/gpu/drm/drm_gem_cma_helper.c
+++ b/drivers/gpu/drm/drm_gem_cma_helper.c
@@ -121,7 +121,7 @@ struct drm_gem_cma_object *drm_gem_cma_c
return cma_obj;

- drm->driver->gem_free_object(&cma_obj->base);
+ drm_gem_object_unreference_unlocked(&cma_obj->base);
return ERR_PTR(ret);
@@ -162,18 +162,12 @@ drm_gem_cma_create_with_handle(struct dr
* and handle has the id what user can see.
ret = drm_gem_handle_create(file_priv, gem_obj, handle);
- if (ret)
- goto err_handle_create;
/* drop reference from allocate - handle holds it now. */
+ if (ret)
+ return ERR_PTR(ret);

return cma_obj;
- drm->driver->gem_free_object(gem_obj);
- return ERR_PTR(ret);