On Wed, Jun 2, 2021 at 6:17 AM Christian König
<ckoenig.leichtzumerken@xxxxxxxxx> 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@xxxxxxx>
> ---
> 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);
Does it make sense to assert we hold the lock *before* we touch it
with something that requires that we do? Maybe it doesn't matter?
> +
> + /* 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.
> + */
> +static inline struct dma_resv_list *dma_resv_shared(struct dma_resv *obj)
Maybe dma_resv_shared_list() just to be a little more clear what's
being returned?
--Jason
> +{
> + 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
>
