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

Christian König ckoenig.leichtzumerken at gmail.com
Sun Jun 6 08:53:22 UTC 2021


Am 02.06.21 um 22:22 schrieb Jason Ekstrand:
> On Wed, Jun 2, 2021 at 6:17 AM Christian König
> <ckoenig.leichtzumerken at gmail.com> 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);
> 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?

As far as I can see that shouldn'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?

Ok, renamed this one and dma_resv_exclusive into dma_resv_excl_fence as 
well.

Christian.

>
> --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
>>



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