From: Boris Brezillon boris.brezillon@collabora.com
commit 7e0cf7e9936c4358b0863357b90aa12afe6489da 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: 013b65101315 ("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... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/panfrost/panfrost_drv.c | 1 + drivers/gpu/drm/panfrost/panfrost_gem.h | 6 ++++++ drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c | 3 +++ drivers/gpu/drm/panfrost/panfrost_job.c | 7 ++++++- 4 files changed, 16 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c @@ -166,6 +166,7 @@ panfrost_lookup_bos(struct drm_device *d break; }
+ atomic_inc(&bo->gpu_usecount); job->mappings[i] = mapping; }
--- a/drivers/gpu/drm/panfrost/panfrost_gem.h +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h @@ -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; }; --- a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c @@ -41,6 +41,9 @@ static bool panfrost_gem_purge(struct dr 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;
--- a/drivers/gpu/drm/panfrost/panfrost_job.c +++ b/drivers/gpu/drm/panfrost/panfrost_job.c @@ -269,8 +269,13 @@ static void panfrost_job_cleanup(struct 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); }