drm/vc4: bo: Fix drmm_mutex_init memory hog

Commit 374146cad469 ("drm/vc4: Switch to drmm_mutex_init") converted,
among other functions, vc4_create_object() to use drmm_mutex_init().

However, that function is used to allocate a BO, and therefore the
mutex needs to be freed much sooner than when the DRM device is removed
from the system.

For each buffer allocation we thus end up allocating a small structure
as part of the DRM-managed mechanism that is never freed, eventually
leading us to no longer having any free memory anymore.

Let's switch back to mutex_init/mutex_destroy to deal with it properly.

Fixes: 374146cad469 ("drm/vc4: Switch to drmm_mutex_init")
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20230112091243.490799-1-maxime@cerno.tech

diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
index 43d9b3a..29ce2fa 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_bo.c
+++ b/drivers/gpu/drm/vc4/vc4_bo.c
@@ -179,6 +179,7 @@ static void vc4_bo_destroy(struct vc4_bo *bo)
                bo->validated_shader = NULL;
        }
 
+       mutex_destroy(&bo->madv_lock);
        drm_gem_dma_free(&bo->base);
 }
 
@@ -406,9 +407,7 @@ struct drm_gem_object *vc4_create_object(struct drm_device *dev, size_t size)
        bo->madv = VC4_MADV_WILLNEED;
        refcount_set(&bo->usecnt, 0);
 
-       ret = drmm_mutex_init(dev, &bo->madv_lock);
-       if (ret)
-               return ERR_PTR(ret);
+       mutex_init(&bo->madv_lock);
 
        mutex_lock(&vc4->bo_lock);
        bo->label = VC4_BO_TYPE_KERNEL;