[PATCH] drm: Wrap direct calls to driver->gem_free_object from CMA

Chris Wilson
2016-05-31T21:25:52Z

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@collabora.com>
Fixes: 9f0ba539d13ae (drm/gem: support BO freeing without dev->struct_mutex)
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Robert Foss <robert.foss@collabora.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: stable@vger.kernel.org
---
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(-)

diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c
index 172cafe11c71..5075fae3c4e2 100644
--- a/drivers/gpu/drm/drm_fb_cma_helper.c
+++ b/drivers/gpu/drm/drm_fb_cma_helper.c
@@ -445,7 +445,7 @@ err_cma_destroy:
err_fb_info_destroy:
drm_fb_helper_release_fbi(helper);
err_gem_free_object:
- dev->driver->gem_free_object(&obj->base);
+ drm_gem_object_unreference_unlocked(&obj->base);
return ret;
}
EXPORT_SYMBOL(drm_fbdev_cma_create_with_funcs);
diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
index e1ab008b3f08..1d6c335584ec 100644
--- 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_create(struct drm_device *drm,
return cma_obj;

error:
- drm->driver->gem_free_object(&cma_obj->base);
+ drm_gem_object_unreference_unlocked(&cma_obj->base);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(drm_gem_cma_create);
@@ -162,18 +162,12 @@ drm_gem_cma_create_with_handle(struct drm_file *file_priv,
* 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. */
drm_gem_object_unreference_unlocked(gem_obj);
+ if (ret)
+ return ERR_PTR(ret);

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

/**
--
2.8.1

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