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drm/panfrost: Make sure the shrinker does not reclaim referenced BOs 

commit 7e0cf7e993 upstream.

Userspace might tag a BO purgeable while it's still referenced by GPU
jobs. We need to make sure the shrinker does not purge such BOs until
all jobs referencing it are finished.

Fixes: 013b651013 ("drm/panfrost: Add madvise and shrinker support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191129135908.2439529-9-boris.brezillon@collabora.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Boris Brezillon 2019-11-29 14:59:08 +01:00 committed by Greg Kroah-Hartman
parent 3ea7f138ce
commit 279c15b917
4 changed files with 16 additions and 1 deletions
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1
drivers/gpu/drm/panfrost/panfrost_drv.c
View File

@ -166,6 +166,7 @@ panfrost_lookup_bos(struct drm_device *dev,
break;
}
atomic_inc(&bo->gpu_usecount);
job->mappings[i] = mapping;
}

6
drivers/gpu/drm/panfrost/panfrost_gem.h
View File

@ -30,6 +30,12 @@ struct panfrost_gem_object {
struct mutex lock;
} mappings;
/*
* Count the number of jobs referencing this BO so we don't let the
* shrinker reclaim this object prematurely.
*/
atomic_t gpu_usecount;
bool noexec :1;
bool is_heap :1;
};

3
drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c
View File

@ -41,6 +41,9 @@ static bool panfrost_gem_purge(struct drm_gem_object *obj)
struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
struct panfrost_gem_object *bo = to_panfrost_bo(obj);
if (atomic_read(&bo->gpu_usecount))
return false;
if (!mutex_trylock(&shmem->pages_lock))
return false;

7
drivers/gpu/drm/panfrost/panfrost_job.c
View File

@ -270,8 +270,13 @@ static void panfrost_job_cleanup(struct kref *ref)
dma_fence_put(job->render_done_fence);
if (job->mappings) {
for (i = 0; i < job->bo_count; i++)
for (i = 0; i < job->bo_count; i++) {
if (!job->mappings[i])
break;
atomic_dec(&job->mappings[i]->obj->gpu_usecount);
panfrost_gem_mapping_put(job->mappings[i]);
}
kvfree(job->mappings);
}