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

On Wed, Jun 2, 2021 at 6:17 AM Christian König ckoenig.leichtzumerken@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@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?

•   /* 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