[PATCH 5/7] dma-buf: rename and cleanup dma_resv_get_list

Daniel Vetter daniel at ffwll.ch
Wed Jun 2 12:46:57 UTC 2021


On Wed, Jun 02, 2021 at 01:17:12PM +0200, Christian König wrote:
> When the comment needs to state explicitly that this is doesn't get a reference
> to the object then the function is named rather badly.
> 
> Rename the function and use it in even more places.
> 
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>  drivers/dma-buf/dma-resv.c                    | 32 +++++++++----------
>  .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  |  2 +-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c   |  2 +-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c      |  2 +-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c       |  2 +-
>  drivers/gpu/drm/etnaviv/etnaviv_gem.c         |  2 +-
>  drivers/gpu/drm/i915/gem/i915_gem_busy.c      |  2 +-
>  drivers/gpu/drm/msm/msm_gem.c                 |  4 +--
>  drivers/gpu/drm/nouveau/nouveau_fence.c       |  2 +-
>  drivers/gpu/drm/qxl/qxl_debugfs.c             |  2 +-
>  drivers/gpu/drm/radeon/radeon_sync.c          |  2 +-
>  drivers/gpu/drm/ttm/ttm_bo.c                  |  2 +-
>  include/linux/dma-resv.h                      | 25 +++++++--------
>  13 files changed, 39 insertions(+), 42 deletions(-)
> 
> diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
> index 81b032b43457..b1a1a31dc009 100644
> --- a/drivers/dma-buf/dma-resv.c
> +++ b/drivers/dma-buf/dma-resv.c
> @@ -149,8 +149,7 @@ int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences)
>  
>  	dma_resv_assert_held(obj);
>  
> -	old = dma_resv_get_list(obj);
> -
> +	old = dma_resv_shared(obj);
>  	if (old && old->shared_max) {
>  		if ((old->shared_count + num_fences) <= old->shared_max)
>  			return 0;
> @@ -217,12 +216,13 @@ EXPORT_SYMBOL(dma_resv_reserve_shared);
>   */
>  void dma_resv_reset_shared_max(struct dma_resv *obj)
>  {
> -	/* Test shared fence slot reservation */
> -	if (rcu_access_pointer(obj->fence)) {
> -		struct dma_resv_list *fence = dma_resv_get_list(obj);
> +	struct dma_resv_list *fences = dma_resv_shared(obj);
>  
> -		fence->shared_max = fence->shared_count;
> -	}
> +	dma_resv_assert_held(obj);
> +
> +	/* Test shared fence slot reservation */
> +	if (fences)
> +		fences->shared_max = fences->shared_count;
>  }
>  #endif
>  
> @@ -244,7 +244,7 @@ void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence)
>  
>  	dma_resv_assert_held(obj);
>  
> -	fobj = dma_resv_get_list(obj);
> +	fobj = dma_resv_shared(obj);
>  	count = fobj->shared_count;
>  
>  	write_seqcount_begin(&obj->seq);
> @@ -287,7 +287,7 @@ void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence)
>  
>  	dma_resv_assert_held(obj);
>  
> -	old = dma_resv_get_list(obj);
> +	old = dma_resv_shared(obj);
>  	if (old)
>  		i = old->shared_count;
>  
> @@ -326,7 +326,7 @@ int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src)
>  	dma_resv_assert_held(dst);
>  
>  	rcu_read_lock();
> -	src_list = rcu_dereference(src->fence);
> +	src_list = dma_resv_shared(src);
>  
>  retry:
>  	if (src_list) {
> @@ -339,7 +339,7 @@ int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src)
>  			return -ENOMEM;
>  
>  		rcu_read_lock();
> -		src_list = rcu_dereference(src->fence);
> +		src_list = dma_resv_shared(src);
>  		if (!src_list || src_list->shared_count > shared_count) {
>  			kfree(dst_list);
>  			goto retry;
> @@ -357,7 +357,7 @@ int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src)
>  
>  			if (!dma_fence_get_rcu(fence)) {
>  				dma_resv_list_free(dst_list);
> -				src_list = rcu_dereference(src->fence);
> +				src_list = dma_resv_shared(src);
>  				goto retry;
>  			}
>  
> @@ -376,7 +376,7 @@ int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src)
>  	new = dma_fence_get_rcu_safe(&src->fence_excl);
>  	rcu_read_unlock();
>  
> -	src_list = dma_resv_get_list(dst);
> +	src_list = dma_resv_shared(dst);
>  	old = dma_resv_exclusive(dst);
>  
>  	write_seqcount_begin(&dst->seq);
> @@ -429,7 +429,7 @@ int dma_resv_get_fences_rcu(struct dma_resv *obj,
>  		if (fence_excl && !dma_fence_get_rcu(fence_excl))
>  			goto unlock;
>  
> -		fobj = rcu_dereference(obj->fence);
> +		fobj = dma_resv_shared(obj);
>  		if (fobj)
>  			sz += sizeof(*shared) * fobj->shared_max;
>  
> @@ -535,7 +535,7 @@ long dma_resv_wait_timeout_rcu(struct dma_resv *obj,
>  	}
>  
>  	if (wait_all) {
> -		struct dma_resv_list *fobj = rcu_dereference(obj->fence);
> +		struct dma_resv_list *fobj = dma_resv_shared(obj);
>  
>  		if (fobj)
>  			shared_count = fobj->shared_count;
> @@ -620,7 +620,7 @@ bool dma_resv_test_signaled_rcu(struct dma_resv *obj, bool test_all)
>  	seq = read_seqcount_begin(&obj->seq);
>  
>  	if (test_all) {
> -		struct dma_resv_list *fobj = rcu_dereference(obj->fence);
> +		struct dma_resv_list *fobj = dma_resv_shared(obj);
>  		unsigned int i;
>  
>  		if (fobj)
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> index d5e6519bdea1..e90495ca49fd 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> @@ -247,7 +247,7 @@ static int amdgpu_amdkfd_remove_eviction_fence(struct amdgpu_bo *bo,
>  	if (!ef)
>  		return -EINVAL;
>  
> -	old = dma_resv_get_list(resv);
> +	old = dma_resv_shared(resv);
>  	if (!old)
>  		return 0;
>  
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> index 6dd0ea6e9e24..3b13c8a38c4e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> @@ -49,7 +49,7 @@ __dma_resv_make_exclusive(struct dma_resv *obj)
>  	unsigned int count;
>  	int r;
>  
> -	if (!dma_resv_get_list(obj)) /* no shared fences to convert */
> +	if (!dma_resv_shared(obj)) /* no shared fences to convert */
>  		return 0;
>  
>  	r = dma_resv_get_fences_rcu(obj, NULL, &count, &fences);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
> index c84d5b843985..c50d9f92a0cd 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
> @@ -213,7 +213,7 @@ int amdgpu_sync_resv(struct amdgpu_device *adev, struct amdgpu_sync *sync,
>  	f = dma_resv_exclusive(resv);
>  	r = amdgpu_sync_fence(sync, f);
>  
> -	flist = dma_resv_get_list(resv);
> +	flist = dma_resv_shared(resv);
>  	if (!flist || r)
>  		return r;
>  
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 663aa7d2e2ea..ddb6ce7d48bc 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -1338,7 +1338,7 @@ static bool amdgpu_ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
>  	 * If true, then return false as any KFD process needs all its BOs to
>  	 * be resident to run successfully
>  	 */
> -	flist = dma_resv_get_list(bo->base.resv);
> +	flist = dma_resv_shared(bo->base.resv);
>  	if (flist) {
>  		for (i = 0; i < flist->shared_count; ++i) {
>  			f = rcu_dereference_protected(flist->shared[i],
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
> index d4f54dea8ac1..4d43b8630f0e 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
> @@ -461,7 +461,7 @@ static void etnaviv_gem_describe(struct drm_gem_object *obj, struct seq_file *m)
>  			off, etnaviv_obj->vaddr, obj->size);
>  
>  	rcu_read_lock();
> -	fobj = rcu_dereference(robj->fence);
> +	fobj = dma_resv_shared(robj);
>  	if (fobj) {
>  		unsigned int i, shared_count = fobj->shared_count;
>  
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_busy.c b/drivers/gpu/drm/i915/gem/i915_gem_busy.c
> index 02312a0c3a36..3f94becac541 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_busy.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_busy.c
> @@ -116,7 +116,7 @@ i915_gem_busy_ioctl(struct drm_device *dev, void *data,
>  	args->busy = busy_check_writer(dma_resv_exclusive(obj->base.resv));
>  
>  	/* Translate shared fences to READ set of engines */
> -	list = rcu_dereference(obj->base.resv->fence);
> +	list = dma_resv_shared(obj->base.resv);
>  	if (list) {
>  		unsigned int shared_count = list->shared_count, i;
>  
> diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
> index 54c1b53426d6..43af91df552e 100644
> --- a/drivers/gpu/drm/msm/msm_gem.c
> +++ b/drivers/gpu/drm/msm/msm_gem.c
> @@ -817,7 +817,7 @@ int msm_gem_sync_object(struct drm_gem_object *obj,
>  	struct dma_fence *fence;
>  	int i, ret;
>  
> -	fobj = dma_resv_get_list(obj->resv);
> +	fobj = dma_resv_shared(obj->resv);
>  	if (!fobj || (fobj->shared_count == 0)) {
>  		fence = dma_resv_exclusive(obj->resv);
>  		/* don't need to wait on our own fences, since ring is fifo */
> @@ -1025,7 +1025,7 @@ void msm_gem_describe(struct drm_gem_object *obj, struct seq_file *m,
>  	}
>  
>  	rcu_read_lock();
> -	fobj = rcu_dereference(robj->fence);
> +	fobj = dma_resv_shared(robj);
>  	if (fobj) {
>  		unsigned int i, shared_count = fobj->shared_count;
>  
> diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c b/drivers/gpu/drm/nouveau/nouveau_fence.c
> index a6cb35181aee..5ce441c655ea 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_fence.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_fence.c
> @@ -355,7 +355,7 @@ nouveau_fence_sync(struct nouveau_bo *nvbo, struct nouveau_channel *chan, bool e
>  			return ret;
>  	}
>  
> -	fobj = dma_resv_get_list(resv);
> +	fobj = dma_resv_shared(resv);
>  	fence = dma_resv_exclusive(resv);
>  
>  	if (fence && (!exclusive || !fobj || !fobj->shared_count)) {
> diff --git a/drivers/gpu/drm/qxl/qxl_debugfs.c b/drivers/gpu/drm/qxl/qxl_debugfs.c
> index 183d15e2cf58..0acc70a6d3dd 100644
> --- a/drivers/gpu/drm/qxl/qxl_debugfs.c
> +++ b/drivers/gpu/drm/qxl/qxl_debugfs.c
> @@ -61,7 +61,7 @@ qxl_debugfs_buffers_info(struct seq_file *m, void *data)
>  		int rel;
>  
>  		rcu_read_lock();
> -		fobj = rcu_dereference(bo->tbo.base.resv->fence);
> +		fobj = dma_resv_shared(bo->tbo.base.resv);
>  		rel = fobj ? fobj->shared_count : 0;
>  		rcu_read_unlock();
>  
> diff --git a/drivers/gpu/drm/radeon/radeon_sync.c b/drivers/gpu/drm/radeon/radeon_sync.c
> index e476f90ef1c1..a9cdb88da173 100644
> --- a/drivers/gpu/drm/radeon/radeon_sync.c
> +++ b/drivers/gpu/drm/radeon/radeon_sync.c
> @@ -105,7 +105,7 @@ int radeon_sync_resv(struct radeon_device *rdev,
>  	else if (f)
>  		r = dma_fence_wait(f, true);
>  
> -	flist = dma_resv_get_list(resv);
> +	flist = dma_resv_shared(resv);
>  	if (shared || !flist || r)
>  		return r;
>  
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 92361556bf0b..c41ef0caa492 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -261,7 +261,7 @@ static void ttm_bo_flush_all_fences(struct ttm_buffer_object *bo)
>  	int i;
>  
>  	rcu_read_lock();
> -	fobj = rcu_dereference(resv->fence);
> +	fobj = dma_resv_shared(resv);
>  	fence = dma_resv_exclusive(resv);
>  	if (fence && !fence->ops->signaled)
>  		dma_fence_enable_sw_signaling(fence);
> diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
> index 7549ec5eb35c..98ac66fecb71 100644
> --- a/include/linux/dma-resv.h
> +++ b/include/linux/dma-resv.h
> @@ -78,20 +78,6 @@ struct dma_resv {
>  #define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base)
>  #define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base)
>  
> -/**
> - * dma_resv_get_list - get the reservation object's
> - * shared fence list, with update-side lock held
> - * @obj: the reservation object
> - *
> - * Returns the shared fence list.  Does NOT take references to
> - * the fence.  The obj->lock must be held.
> - */
> -static inline struct dma_resv_list *dma_resv_get_list(struct dma_resv *obj)
> -{
> -	return rcu_dereference_protected(obj->fence,
> -					 dma_resv_held(obj));
> -}
> -
>  #ifdef CONFIG_DEBUG_MUTEXES
>  void dma_resv_reset_shared_max(struct dma_resv *obj);
>  #else
> @@ -267,6 +253,17 @@ dma_resv_get_excl_rcu(struct dma_resv *obj)
>  	return fence;
>  }
>  
> +/**
> + * dma_resv_shared - get the reservation object's shared fence list
> + * @obj: the reservation object
> + *
> + * Returns the shared fence list. The obj->lock or rcu read side must be held.

Please copypaste the same wording from dma_resv_exclusive with all the
links to dma_resv_lock() and rcu_read_lock() here to make the kerneldoc
more useful.

Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>

> + */
> +static inline struct dma_resv_list *dma_resv_shared(struct dma_resv *obj)
> +{
> +	return rcu_dereference_check(obj->fence, dma_resv_held(obj));
> +}
> +
>  void dma_resv_init(struct dma_resv *obj);
>  void dma_resv_fini(struct dma_resv *obj);
>  int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences);
> -- 
> 2.25.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch


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