dma-buf: specify usage while adding fences to dma_resv obj v7

Instead of distingting between shared and exclusive fences specify
the fence usage while adding fences.

Rework all drivers to use this interface instead and deprecate the old one.

v2: some kerneldoc comments suggested by Daniel
v3: fix a missing case in radeon
v4: rebase on nouveau changes, fix lockdep and temporary disable warning
v5: more documentation updates
v6: separate internal dma_resv changes from this patch, avoids to
    disable warning temporary, rebase on upstream changes
v7: fix missed case in lima driver, minimize changes to i915_gem_busy_ioctl

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-3-christian.koenig@amd.com

30 files changed, 149 insertions, 166 deletions

diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
index 17237e6ee30c..543dae6566d2 100644
--- a/drivers/dma-buf/dma-resv.c
+++ b/drivers/dma-buf/dma-resv.c
@@ -234,14 +234,14 @@ EXPORT_SYMBOL(dma_resv_reserve_fences);
 
 #ifdef CONFIG_DEBUG_MUTEXES
 /**
- * dma_resv_reset_shared_max - reset shared fences for debugging
+ * dma_resv_reset_max_fences - reset shared fences for debugging
  * @obj: the dma_resv object to reset
  *
  * Reset the number of pre-reserved shared slots to test that drivers do
  * correct slot allocation using dma_resv_reserve_fences(). See also
  * &dma_resv_list.shared_max.
  */
-void dma_resv_reset_shared_max(struct dma_resv *obj)
+void dma_resv_reset_max_fences(struct dma_resv *obj)
 {
 	struct dma_resv_list *fences = dma_resv_shared_list(obj);
 
@@ -251,7 +251,7 @@ void dma_resv_reset_shared_max(struct dma_resv *obj)
 	if (fences)
 		fences->shared_max = fences->shared_count;
 }
-EXPORT_SYMBOL(dma_resv_reset_shared_max);
+EXPORT_SYMBOL(dma_resv_reset_max_fences);
 #endif
 
 /**
@@ -264,7 +264,8 @@ EXPORT_SYMBOL(dma_resv_reset_shared_max);
  *
  * See also &dma_resv.fence for a discussion of the semantics.
  */
-void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence)
+static void dma_resv_add_shared_fence(struct dma_resv *obj,
+				      struct dma_fence *fence)
 {
 	struct dma_resv_list *fobj;
 	struct dma_fence *old;
@@ -305,13 +306,13 @@ replace:
 	write_seqcount_end(&obj->seq);
 	dma_fence_put(old);
 }
-EXPORT_SYMBOL(dma_resv_add_shared_fence);
 
 /**
  * dma_resv_replace_fences - replace fences in the dma_resv obj
  * @obj: the reservation object
  * @context: the context of the fences to replace
  * @replacement: the new fence to use instead
+ * @usage: how the new fence is used, see enum dma_resv_usage
  *
  * Replace fences with a specified context with a new fence. Only valid if the
  * operation represented by the original fence has no longer access to the
@@ -321,12 +322,16 @@ EXPORT_SYMBOL(dma_resv_add_shared_fence);
  * update fence which makes the resource inaccessible.
  */
 void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context,
-			     struct dma_fence *replacement)
+			     struct dma_fence *replacement,
+			     enum dma_resv_usage usage)
 {
 	struct dma_resv_list *list;
 	struct dma_fence *old;
 	unsigned int i;
 
+	/* Only readers supported for now */
+	WARN_ON(usage != DMA_RESV_USAGE_READ);
+
 	dma_resv_assert_held(obj);
 
 	write_seqcount_begin(&obj->seq);
@@ -360,7 +365,8 @@ EXPORT_SYMBOL(dma_resv_replace_fences);
  * Add a fence to the exclusive slot. @obj must be locked with dma_resv_lock().
  * See also &dma_resv.fence_excl for a discussion of the semantics.
  */
-void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence)
+static void dma_resv_add_excl_fence(struct dma_resv *obj,
+				    struct dma_fence *fence)
 {
 	struct dma_fence *old_fence = dma_resv_excl_fence(obj);
 
@@ -375,7 +381,27 @@ void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence)
 
 	dma_fence_put(old_fence);
 }
-EXPORT_SYMBOL(dma_resv_add_excl_fence);
+
+/**
+ * dma_resv_add_fence - Add a fence to the dma_resv obj
+ * @obj: the reservation object
+ * @fence: the fence to add
+ * @usage: how the fence is used, see enum dma_resv_usage
+ *
+ * Add a fence to a slot, @obj must be locked with dma_resv_lock(), and
+ * dma_resv_reserve_fences() has been called.
+ *
+ * See also &dma_resv.fence for a discussion of the semantics.
+ */
+void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence,
+			enum dma_resv_usage usage)
+{
+	if (usage == DMA_RESV_USAGE_WRITE)
+		dma_resv_add_excl_fence(obj, fence);
+	else
+		dma_resv_add_shared_fence(obj, fence);
+}
+EXPORT_SYMBOL(dma_resv_add_fence);
 
 /* Restart the iterator by initializing all the necessary fields, but not the
  * relation to the dma_resv object. */
@@ -574,7 +600,7 @@ int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src)
 		}
 
 		dma_fence_get(f);
-		if (dma_resv_iter_is_exclusive(&cursor))
+		if (dma_resv_iter_usage(&cursor) == DMA_RESV_USAGE_WRITE)
 			excl = f;
 		else
 			RCU_INIT_POINTER(list->shared[list->shared_count++], f);
@@ -771,13 +797,13 @@ EXPORT_SYMBOL_GPL(dma_resv_test_signaled);
  */
 void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq)
 {
+	static const char *usage[] = { "write", "read" };
 	struct dma_resv_iter cursor;
 	struct dma_fence *fence;
 
 	dma_resv_for_each_fence(&cursor, obj, DMA_RESV_USAGE_READ, fence) {
 		seq_printf(seq, "\t%s fence:",
-			   dma_resv_iter_is_exclusive(&cursor) ?
-				"Exclusive" : "Shared");
+			   usage[dma_resv_iter_usage(&cursor)]);
 		dma_fence_describe(fence, seq);
 	}
 }
diff --git a/drivers/dma-buf/st-dma-resv.c b/drivers/dma-buf/st-dma-resv.c
index d097981061b1..d0f7c2bfd4f0 100644
--- a/drivers/dma-buf/st-dma-resv.c
+++ b/drivers/dma-buf/st-dma-resv.c
@@ -58,8 +58,9 @@ static int sanitycheck(void *arg)
 	return r;
 }
 
-static int test_signaling(void *arg, enum dma_resv_usage usage)
+static int test_signaling(void *arg)
 {
+	enum dma_resv_usage usage = (unsigned long)arg;
 	struct dma_resv resv;
 	struct dma_fence *f;
 	int r;
@@ -81,11 +82,7 @@ static int test_signaling(void *arg, enum dma_resv_usage usage)
 		goto err_unlock;
 	}
 
-	if (usage >= DMA_RESV_USAGE_READ)
-		dma_resv_add_shared_fence(&resv, f);
-	else
-		dma_resv_add_excl_fence(&resv, f);
-
+	dma_resv_add_fence(&resv, f, usage);
 	if (dma_resv_test_signaled(&resv, usage)) {
 		pr_err("Resv unexpectedly signaled\n");
 		r = -EINVAL;
@@ -105,18 +102,9 @@ err_free:
 	return r;
 }
 
-static int test_excl_signaling(void *arg)
-{
-	return test_signaling(arg, DMA_RESV_USAGE_WRITE);
-}
-
-static int test_shared_signaling(void *arg)
-{
-	return test_signaling(arg, DMA_RESV_USAGE_READ);
-}
-
-static int test_for_each(void *arg, enum dma_resv_usage usage)
+static int test_for_each(void *arg)
 {
+	enum dma_resv_usage usage = (unsigned long)arg;
 	struct dma_resv_iter cursor;
 	struct dma_fence *f, *fence;
 	struct dma_resv resv;
@@ -139,10 +127,7 @@ static int test_for_each(void *arg, enum dma_resv_usage usage)
 		goto err_unlock;
 	}
 
-	if (usage >= DMA_RESV_USAGE_READ)
-		dma_resv_add_shared_fence(&resv, f);
-	else
-		dma_resv_add_excl_fence(&resv, f);
+	dma_resv_add_fence(&resv, f, usage);
 
 	r = -ENOENT;
 	dma_resv_for_each_fence(&cursor, &resv, usage, fence) {
@@ -156,8 +141,7 @@ static int test_for_each(void *arg, enum dma_resv_usage usage)
 			r = -EINVAL;
 			goto err_unlock;
 		}
-		if (dma_resv_iter_is_exclusive(&cursor) !=
-		    (usage >= DMA_RESV_USAGE_READ)) {
+		if (dma_resv_iter_usage(&cursor) != usage) {
 			pr_err("Unexpected fence usage\n");
 			r = -EINVAL;
 			goto err_unlock;
@@ -177,18 +161,9 @@ err_free:
 	return r;
 }
 
-static int test_excl_for_each(void *arg)
-{
-	return test_for_each(arg, DMA_RESV_USAGE_WRITE);
-}
-
-static int test_shared_for_each(void *arg)
-{
-	return test_for_each(arg, DMA_RESV_USAGE_READ);
-}
-
-static int test_for_each_unlocked(void *arg, enum dma_resv_usage usage)
+static int test_for_each_unlocked(void *arg)
 {
+	enum dma_resv_usage usage = (unsigned long)arg;
 	struct dma_resv_iter cursor;
 	struct dma_fence *f, *fence;
 	struct dma_resv resv;
@@ -212,10 +187,7 @@ static int test_for_each_unlocked(void *arg, enum dma_resv_usage usage)
 		goto err_free;
 	}
 
-	if (usage >= DMA_RESV_USAGE_READ)
-		dma_resv_add_shared_fence(&resv, f);
-	else
-		dma_resv_add_excl_fence(&resv, f);
+	dma_resv_add_fence(&resv, f, usage);
 	dma_resv_unlock(&resv);
 
 	r = -ENOENT;
@@ -235,8 +207,7 @@ static int test_for_each_unlocked(void *arg, enum dma_resv_usage usage)
 			r = -EINVAL;
 			goto err_iter_end;
 		}
-		if (dma_resv_iter_is_exclusive(&cursor) !=
-		    (usage >= DMA_RESV_USAGE_READ)) {
+		if (dma_resv_iter_usage(&cursor) != usage) {
 			pr_err("Unexpected fence usage\n");
 			r = -EINVAL;
 			goto err_iter_end;
@@ -262,18 +233,9 @@ err_free:
 	return r;
 }
 
-static int test_excl_for_each_unlocked(void *arg)
-{
-	return test_for_each_unlocked(arg, DMA_RESV_USAGE_WRITE);
-}
-
-static int test_shared_for_each_unlocked(void *arg)
-{
-	return test_for_each_unlocked(arg, DMA_RESV_USAGE_READ);
-}
-
-static int test_get_fences(void *arg, enum dma_resv_usage usage)
+static int test_get_fences(void *arg)
 {
+	enum dma_resv_usage usage = (unsigned long)arg;
 	struct dma_fence *f, **fences = NULL;
 	struct dma_resv resv;
 	int r, i;
@@ -296,10 +258,7 @@ static int test_get_fences(void *arg, enum dma_resv_usage usage)
 		goto err_resv;
 	}
 
-	if (usage >= DMA_RESV_USAGE_READ)
-		dma_resv_add_shared_fence(&resv, f);
-	else
-		dma_resv_add_excl_fence(&resv, f);
+	dma_resv_add_fence(&resv, f, usage);
 	dma_resv_unlock(&resv);
 
 	r = dma_resv_get_fences(&resv, usage, &i, &fences);
@@ -324,30 +283,24 @@ err_resv:
 	return r;
 }
 
-static int test_excl_get_fences(void *arg)
-{
-	return test_get_fences(arg, DMA_RESV_USAGE_WRITE);
-}
-
-static int test_shared_get_fences(void *arg)
-{
-	return test_get_fences(arg, DMA_RESV_USAGE_READ);
-}
-
 int dma_resv(void)
 {
 	static const struct subtest tests[] = {
 		SUBTEST(sanitycheck),
-		SUBTEST(test_excl_signaling),
-		SUBTEST(test_shared_signaling),
-		SUBTEST(test_excl_for_each),
-		SUBTEST(test_shared_for_each),
-		SUBTEST(test_excl_for_each_unlocked),
-		SUBTEST(test_shared_for_each_unlocked),
-		SUBTEST(test_excl_get_fences),
-		SUBTEST(test_shared_get_fences),
+		SUBTEST(test_signaling),
+		SUBTEST(test_for_each),
+		SUBTEST(test_for_each_unlocked),
+		SUBTEST(test_get_fences),
 	};
+	enum dma_resv_usage usage;
+	int r;
 
 	spin_lock_init(&fence_lock);
-	return subtests(tests, NULL);
+	for (usage = DMA_RESV_USAGE_WRITE; usage <= DMA_RESV_USAGE_READ;
+	     ++usage) {
+		r = subtests(tests, (void *)(unsigned long)usage);
+		if (r)
+			return r;
+	}
+	return 0;
 }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index 98b1736bb221..5031e26e6716 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -263,7 +263,7 @@ static int amdgpu_amdkfd_remove_eviction_fence(struct amdgpu_bo *bo,
 	 */
 	replacement = dma_fence_get_stub();
 	dma_resv_replace_fences(bo->tbo.base.resv, ef->base.context,
-				replacement);
+				replacement, DMA_RESV_USAGE_READ);
 	dma_fence_put(replacement);
 	return 0;
 }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 413f32c3fd63..76fd916424d6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -55,8 +55,8 @@ static int amdgpu_cs_user_fence_chunk(struct amdgpu_cs_parser *p,
 	bo = amdgpu_bo_ref(gem_to_amdgpu_bo(gobj));
 	p->uf_entry.priority = 0;
 	p->uf_entry.tv.bo = &bo->tbo;
-	/* One for TTM and one for the CS job */
-	p->uf_entry.tv.num_shared = 2;
+	/* One for TTM and two for the CS job */
+	p->uf_entry.tv.num_shared = 3;
 
 	drm_gem_object_put(gobj);
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index a7f39f8ab7be..a3cdf8a24377 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -1397,10 +1397,8 @@ void amdgpu_bo_fence(struct amdgpu_bo *bo, struct dma_fence *fence,
 		return;
 	}
 
-	if (shared)
-		dma_resv_add_shared_fence(resv, fence);
-	else
-		dma_resv_add_excl_fence(resv, fence);
+	dma_resv_add_fence(resv, fence, shared ? DMA_RESV_USAGE_READ :
+			   DMA_RESV_USAGE_WRITE);
 }
 
 /**
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c b/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c
index 53f7c78628a4..98bb5c9239de 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c
@@ -202,14 +202,10 @@ static void submit_attach_object_fences(struct etnaviv_gem_submit *submit)
 
 	for (i = 0; i < submit->nr_bos; i++) {
 		struct drm_gem_object *obj = &submit->bos[i].obj->base;
+		bool write = submit->bos[i].flags & ETNA_SUBMIT_BO_WRITE;
 
-		if (submit->bos[i].flags & ETNA_SUBMIT_BO_WRITE)
-			dma_resv_add_excl_fence(obj->resv,
-							  submit->out_fence);
-		else
-			dma_resv_add_shared_fence(obj->resv,
-							    submit->out_fence);
-
+		dma_resv_add_fence(obj->resv, submit->out_fence, write ?
+				   DMA_RESV_USAGE_WRITE : DMA_RESV_USAGE_READ);
 		submit_unlock_object(submit, i);
 	}
 }
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_busy.c b/drivers/gpu/drm/i915/gem/i915_gem_busy.c
index 14a1c0ad8c3c..ddda468241ef 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_busy.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_busy.c
@@ -148,11 +148,11 @@ i915_gem_busy_ioctl(struct drm_device *dev, void *data,
 		if (dma_resv_iter_is_restarted(&cursor))
 			args->busy = 0;
 
-		if (dma_resv_iter_is_exclusive(&cursor))
-			/* Translate the exclusive fence to the READ *and* WRITE engine */
+		if (dma_resv_iter_usage(&cursor) <= DMA_RESV_USAGE_WRITE)
+			/* Translate the write fences to the READ *and* WRITE engine */
 			args->busy |= busy_check_writer(fence);
 		else
-			/* Translate shared fences to READ set of engines */
+			/* Translate read fences to READ set of engines */
 			args->busy |= busy_check_reader(fence);
 	}
 	dma_resv_iter_end(&cursor);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_clflush.c b/drivers/gpu/drm/i915/gem/i915_gem_clflush.c
index 1fd0cc9ca213..f5f2b8b115ea 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_clflush.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_clflush.c
@@ -116,7 +116,8 @@ bool i915_gem_clflush_object(struct drm_i915_gem_object *obj,
 						obj->base.resv, NULL, true,
 						i915_fence_timeout(i915),
 						I915_FENCE_GFP);
-		dma_resv_add_excl_fence(obj->base.resv, &clflush->base.dma);
+		dma_resv_add_fence(obj->base.resv, &clflush->base.dma,
+				   DMA_RESV_USAGE_WRITE);
 		dma_fence_work_commit(&clflush->base);
 		/*
 		 * We must have successfully populated the pages(since we are
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
index 432ac74ff225..438b8a95b3d1 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
@@ -637,9 +637,8 @@ int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
 	if (IS_ERR_OR_NULL(copy_fence))
 		return PTR_ERR_OR_ZERO(copy_fence);
 
-	dma_resv_add_excl_fence(dst_bo->base.resv, copy_fence);
-	dma_resv_add_shared_fence(src_bo->base.resv, copy_fence);
-
+	dma_resv_add_fence(dst_bo->base.resv, copy_fence, DMA_RESV_USAGE_WRITE);
+	dma_resv_add_fence(src_bo->base.resv, copy_fence, DMA_RESV_USAGE_READ);
 	dma_fence_put(copy_fence);
 
 	return 0;
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_migrate.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_migrate.c
index 0e52eb87cd55..4997ed18b6e4 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_migrate.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_migrate.c
@@ -218,8 +218,8 @@ static int __igt_lmem_pages_migrate(struct intel_gt *gt,
 		if (rq) {
 			err = dma_resv_reserve_fences(obj->base.resv, 1);
 			if (!err)
-				dma_resv_add_excl_fence(obj->base.resv,
-							&rq->fence);
+				dma_resv_add_fence(obj->base.resv, &rq->fence,
+						   DMA_RESV_USAGE_WRITE);
 			i915_gem_object_set_moving_fence(obj, &rq->fence);
 			i915_request_put(rq);
 		}
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
index a132e241c3ee..3a6e3f6d239f 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
@@ -1220,7 +1220,8 @@ static int __igt_mmap_migrate(struct intel_memory_region **placements,
 					  expand32(POISON_INUSE), &rq);
 	i915_gem_object_unpin_pages(obj);
 	if (rq) {
-		dma_resv_add_excl_fence(obj->base.resv, &rq->fence);
+		dma_resv_add_fence(obj->base.resv, &rq->fence,
+				   DMA_RESV_USAGE_WRITE);
 		i915_gem_object_set_moving_fence(obj, &rq->fence);
 		i915_request_put(rq);
 	}
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index bae3423f58e8..524477d8939e 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -1826,7 +1826,8 @@ int _i915_vma_move_to_active(struct i915_vma *vma,
 		}
 
 		if (fence) {
-			dma_resv_add_excl_fence(vma->obj->base.resv, fence);
+			dma_resv_add_fence(vma->obj->base.resv, fence,
+					   DMA_RESV_USAGE_WRITE);
 			obj->write_domain = I915_GEM_DOMAIN_RENDER;
 			obj->read_domains = 0;
 		}
@@ -1838,7 +1839,8 @@ int _i915_vma_move_to_active(struct i915_vma *vma,
 		}
 
 		if (fence) {
-			dma_resv_add_shared_fence(vma->obj->base.resv, fence);
+			dma_resv_add_fence(vma->obj->base.resv, fence,
+					   DMA_RESV_USAGE_READ);
 			obj->write_domain = 0;
 		}
 	}
@@ -2078,7 +2080,7 @@ int i915_vma_unbind_async(struct i915_vma *vma, bool trylock_vm)
 		goto out_rpm;
 	}
 
-	dma_resv_add_shared_fence(obj->base.resv, fence);
+	dma_resv_add_fence(obj->base.resv, fence, DMA_RESV_USAGE_READ);
 	dma_fence_put(fence);
 
 out_rpm:
diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
index 6114e013092b..73eb53edb8de 100644
--- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
@@ -1056,7 +1056,8 @@ static int igt_lmem_write_cpu(void *arg)
 					  obj->mm.pages->sgl, I915_CACHE_NONE,
 					  true, 0xdeadbeaf, &rq);
 	if (rq) {
-		dma_resv_add_excl_fence(obj->base.resv, &rq->fence);
+		dma_resv_add_fence(obj->base.resv, &rq->fence,
+				   DMA_RESV_USAGE_WRITE);
 		i915_request_put(rq);
 	}
 
diff --git a/drivers/gpu/drm/lima/lima_gem.c b/drivers/gpu/drm/lima/lima_gem.c
index e0a11ee0e86d..0f1ca0b0db49 100644
--- a/drivers/gpu/drm/lima/lima_gem.c
+++ b/drivers/gpu/drm/lima/lima_gem.c
@@ -364,10 +364,9 @@ int lima_gem_submit(struct drm_file *file, struct lima_submit *submit)
 	fence = lima_sched_context_queue_task(submit->task);
 
 	for (i = 0; i < submit->nr_bos; i++) {
-		if (submit->bos[i].flags & LIMA_SUBMIT_BO_WRITE)
-			dma_resv_add_excl_fence(lima_bo_resv(bos[i]), fence);
-		else
-			dma_resv_add_shared_fence(lima_bo_resv(bos[i]), fence);
+		dma_resv_add_fence(lima_bo_resv(bos[i]), fence,
+				   submit->bos[i].flags & LIMA_SUBMIT_BO_WRITE ?
+				   DMA_RESV_USAGE_WRITE : DMA_RESV_USAGE_READ);
 	}
 
 	drm_gem_unlock_reservations((struct drm_gem_object **)bos,
diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
index 3164db8be893..8d1eef914ba8 100644
--- a/drivers/gpu/drm/msm/msm_gem_submit.c
+++ b/drivers/gpu/drm/msm/msm_gem_submit.c
@@ -395,9 +395,11 @@ static void submit_attach_object_fences(struct msm_gem_submit *submit)
 		struct drm_gem_object *obj = &submit->bos[i].obj->base;
 
 		if (submit->bos[i].flags & MSM_SUBMIT_BO_WRITE)
-			dma_resv_add_excl_fence(obj->resv, submit->user_fence);
+			dma_resv_add_fence(obj->resv, submit->user_fence,
+					   DMA_RESV_USAGE_WRITE);
 		else if (submit->bos[i].flags & MSM_SUBMIT_BO_READ)
-			dma_resv_add_shared_fence(obj->resv, submit->user_fence);
+			dma_resv_add_fence(obj->resv, submit->user_fence,
+					   DMA_RESV_USAGE_READ);
 	}
 }
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index c6bb4dbcd735..05076e530e7d 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -1308,10 +1308,11 @@ nouveau_bo_fence(struct nouveau_bo *nvbo, struct nouveau_fence *fence, bool excl
 {
 	struct dma_resv *resv = nvbo->bo.base.resv;
 
-	if (exclusive)
-		dma_resv_add_excl_fence(resv, &fence->base);
-	else if (fence)
-		dma_resv_add_shared_fence(resv, &fence->base);
+	if (!fence)
+		return;
+
+	dma_resv_add_fence(resv, &fence->base, exclusive ?
+			   DMA_RESV_USAGE_WRITE : DMA_RESV_USAGE_READ);
 }
 
 static void
diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c b/drivers/gpu/drm/nouveau/nouveau_fence.c
index d5e81ccee01c..7f01dcf81fab 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fence.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fence.c
@@ -360,9 +360,11 @@ nouveau_fence_sync(struct nouveau_bo *nvbo, struct nouveau_channel *chan,
 		dma_resv_for_each_fence(&cursor, resv,
 					dma_resv_usage_rw(exclusive),
 					fence) {
+			enum dma_resv_usage usage;
 			struct nouveau_fence *f;
 
-			if (i == 0 && dma_resv_iter_is_exclusive(&cursor))
+			usage = dma_resv_iter_usage(&cursor);
+			if (i == 0 && usage == DMA_RESV_USAGE_WRITE)
 				continue;
 
 			f = nouveau_local_fence(fence, chan->drm);
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index c34114560e49..fda5871aebe3 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -268,7 +268,7 @@ static void panfrost_attach_object_fences(struct drm_gem_object **bos,
 	int i;
 
 	for (i = 0; i < bo_count; i++)
-		dma_resv_add_excl_fence(bos[i]->resv, fence);
+		dma_resv_add_fence(bos[i]->resv, fence, DMA_RESV_USAGE_WRITE);
 }
 
 int panfrost_job_push(struct panfrost_job *job)
diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index cde1e8ddaeaa..368d26da0d6a 100644
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -429,7 +429,8 @@ void qxl_release_fence_buffer_objects(struct qxl_release *release)
 	list_for_each_entry(entry, &release->bos, head) {
 		bo = entry->bo;
 
-		dma_resv_add_shared_fence(bo->base.resv, &release->base);
+		dma_resv_add_fence(bo->base.resv, &release->base,
+				   DMA_RESV_USAGE_READ);
 		ttm_bo_move_to_lru_tail_unlocked(bo);
 		dma_resv_unlock(bo->base.resv);
 	}
diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index 7ffd2e90f325..cb5c4aa45cef 100644
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -791,8 +791,6 @@ void radeon_bo_fence(struct radeon_bo *bo, struct radeon_fence *fence,
 		return;
 	}
 
-	if (shared)
-		dma_resv_add_shared_fence(resv, &fence->base);
-	else
-		dma_resv_add_excl_fence(resv, &fence->base);
+	dma_resv_add_fence(resv, &fence->base, shared ?
+			   DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE);
 }
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index cff05b62f3f7..d74f9eea855e 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -739,7 +739,7 @@ static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo,
 		return ret;
 	}
 
-	dma_resv_add_shared_fence(bo->base.resv, fence);
+	dma_resv_add_fence(bo->base.resv, fence, DMA_RESV_USAGE_WRITE);
 
 	ret = dma_resv_reserve_fences(bo->base.resv, 1);
 	if (unlikely(ret)) {
diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 1b96b91bf81b..7a96a1db13a7 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -507,7 +507,8 @@ static int ttm_bo_move_to_ghost(struct ttm_buffer_object *bo,
 	if (ret)
 		return ret;
 
-	dma_resv_add_excl_fence(&ghost_obj->base._resv, fence);
+	dma_resv_add_fence(&ghost_obj->base._resv, fence,
+			   DMA_RESV_USAGE_WRITE);
 
 	/**
 	 * If we're not moving to fixed memory, the TTM object
@@ -561,7 +562,7 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
 	struct ttm_resource_manager *man = ttm_manager_type(bdev, new_mem->mem_type);
 	int ret = 0;
 
-	dma_resv_add_excl_fence(bo->base.resv, fence);
+	dma_resv_add_fence(bo->base.resv, fence, DMA_RESV_USAGE_WRITE);
 	if (!evict)
 		ret = ttm_bo_move_to_ghost(bo, fence, man->use_tt);
 	else if (!from->use_tt && pipeline)
diff --git a/drivers/gpu/drm/ttm/ttm_execbuf_util.c b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
index 789c645f004e..0eb995d25df1 100644
--- a/drivers/gpu/drm/ttm/ttm_execbuf_util.c
+++ b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
@@ -154,10 +154,8 @@ void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
 	list_for_each_entry(entry, list, head) {
 		struct ttm_buffer_object *bo = entry->bo;
 
-		if (entry->num_shared)
-			dma_resv_add_shared_fence(bo->base.resv, fence);
-		else
-			dma_resv_add_excl_fence(bo->base.resv, fence);
+		dma_resv_add_fence(bo->base.resv, fence, entry->num_shared ?
+				   DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE);
 		ttm_bo_move_to_lru_tail_unlocked(bo);
 		dma_resv_unlock(bo->base.resv);
 	}
diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
index 961812d33827..2352e9640922 100644
--- a/drivers/gpu/drm/v3d/v3d_gem.c
+++ b/drivers/gpu/drm/v3d/v3d_gem.c
@@ -550,8 +550,8 @@ v3d_attach_fences_and_unlock_reservation(struct drm_file *file_priv,
 
 	for (i = 0; i < job->bo_count; i++) {
 		/* XXX: Use shared fences for read-only objects. */
-		dma_resv_add_excl_fence(job->bo[i]->resv,
-					job->done_fence);
+		dma_resv_add_fence(job->bo[i]->resv, job->done_fence,
+				   DMA_RESV_USAGE_WRITE);
 	}
 
 	drm_gem_unlock_reservations(job->bo, job->bo_count, acquire_ctx);
diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c
index 594bd6bb00d2..38550317e025 100644
--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -546,7 +546,7 @@ vc4_update_bo_seqnos(struct vc4_exec_info *exec, uint64_t seqno)
 		bo = to_vc4_bo(&exec->bo[i]->base);
 		bo->seqno = seqno;
 
-		dma_resv_add_shared_fence(bo->base.base.resv, exec->fence);
+		dma_resv_add_fence(bo->base.base.resv, exec->fence);
 	}
 
 	list_for_each_entry(bo, &exec->unref_list, unref_head) {
diff --git a/drivers/gpu/drm/vgem/vgem_fence.c b/drivers/gpu/drm/vgem/vgem_fence.c
index 91fc4940c65a..c2a879734d40 100644
--- a/drivers/gpu/drm/vgem/vgem_fence.c
+++ b/drivers/gpu/drm/vgem/vgem_fence.c
@@ -161,12 +161,9 @@ int vgem_fence_attach_ioctl(struct drm_device *dev,
 	/* Expose the fence via the dma-buf */
 	dma_resv_lock(resv, NULL);
 	ret = dma_resv_reserve_fences(resv, 1);
-	if (!ret) {
-		if (arg->flags & VGEM_FENCE_WRITE)
-			dma_resv_add_excl_fence(resv, fence);
-		else
-			dma_resv_add_shared_fence(resv, fence);
-	}
+	if (!ret)
+		dma_resv_add_fence(resv, fence, arg->flags & VGEM_FENCE_WRITE ?
+				   DMA_RESV_USAGE_WRITE : DMA_RESV_USAGE_READ);
 	dma_resv_unlock(resv);
 
 	/* Record the fence in our idr for later signaling */
diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
index 1820ca6cf673..580a78809836 100644
--- a/drivers/gpu/drm/virtio/virtgpu_gem.c
+++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
@@ -250,7 +250,8 @@ void virtio_gpu_array_add_fence(struct virtio_gpu_object_array *objs,
 	int i;
 
 	for (i = 0; i < objs->nents; i++)
-		dma_resv_add_excl_fence(objs->objs[i]->resv, fence);
+		dma_resv_add_fence(objs->objs[i]->resv, fence,
+				   DMA_RESV_USAGE_WRITE);
 }
 
 void virtio_gpu_array_put_free(struct virtio_gpu_object_array *objs)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
index b96884f7d03d..bec50223efe5 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
@@ -758,7 +758,8 @@ void vmw_bo_fence_single(struct ttm_buffer_object *bo,
 
 	ret = dma_resv_reserve_fences(bo->base.resv, 1);
 	if (!ret)
-		dma_resv_add_excl_fence(bo->base.resv, &fence->base);
+		dma_resv_add_fence(bo->base.resv, &fence->base,
+				   DMA_RESV_USAGE_WRITE);
 	else
 		/* Last resort fallback when we are OOM */
 		dma_fence_wait(&fence->base, false);
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index a297397743a2..71731796c8c3 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -393,15 +393,15 @@ struct dma_buf {
 	 * e.g. exposed in `Implicit Fence Poll Support`_ must follow the
 	 * below rules.
 	 *
-	 * - Drivers must add a shared fence through dma_resv_add_shared_fence()
-	 *   for anything the userspace API considers a read access. This highly
-	 *   depends upon the API and window system.
+	 * - Drivers must add a read fence through dma_resv_add_fence() with the
+	 *   DMA_RESV_USAGE_READ flag for anything the userspace API considers a
+	 *   read access. This highly depends upon the API and window system.
 	 *
-	 * - Similarly drivers must set the exclusive fence through
-	 *   dma_resv_add_excl_fence() for anything the userspace API considers
-	 *   write access.
+	 * - Similarly drivers must add a write fence through
+	 *   dma_resv_add_fence() with the DMA_RESV_USAGE_WRITE flag for
+	 *   anything the userspace API considers write access.
 	 *
-	 * - Drivers may just always set the exclusive fence, since that only
+	 * - Drivers may just always add a write fence, since that only
 	 *   causes unecessarily synchronization, but no correctness issues.
 	 *
 	 * - Some drivers only expose a synchronous userspace API with no
@@ -416,7 +416,7 @@ struct dma_buf {
 	 * Dynamic importers, see dma_buf_attachment_is_dynamic(), have
 	 * additional constraints on how they set up fences:
 	 *
-	 * - Dynamic importers must obey the exclusive fence and wait for it to
+	 * - Dynamic importers must obey the write fences and wait for them to
 	 *   signal before allowing access to the buffer's underlying storage
 	 *   through the device.
 	 *
diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
index 92cd8023980f..98dc5234b487 100644
--- a/include/linux/dma-resv.h
+++ b/include/linux/dma-resv.h
@@ -195,6 +195,9 @@ struct dma_resv_iter {
 	/** @fence: the currently handled fence */
 	struct dma_fence *fence;
 
+	/** @fence_usage: the usage of the current fence */
+	enum dma_resv_usage fence_usage;
+
 	/** @seq: sequence number to check for modifications */
 	unsigned int seq;
 
@@ -244,14 +247,15 @@ static inline void dma_resv_iter_end(struct dma_resv_iter *cursor)
 }
 
 /**
- * dma_resv_iter_is_exclusive - test if the current fence is the exclusive one
+ * dma_resv_iter_usage - Return the usage of the current fence
  * @cursor: the cursor of the current position
  *
- * Returns true if the currently returned fence is the exclusive one.
+ * Returns the usage of the currently processed fence.
  */
-static inline bool dma_resv_iter_is_exclusive(struct dma_resv_iter *cursor)
+static inline enum dma_resv_usage
+dma_resv_iter_usage(struct dma_resv_iter *cursor)
 {
-	return cursor->index == 0;
+	return cursor->fence_usage;
 }
 
 /**
@@ -306,9 +310,9 @@ static inline bool dma_resv_iter_is_restarted(struct dma_resv_iter *cursor)
 #define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base)
 
 #ifdef CONFIG_DEBUG_MUTEXES
-void dma_resv_reset_shared_max(struct dma_resv *obj);
+void dma_resv_reset_max_fences(struct dma_resv *obj);
 #else
-static inline void dma_resv_reset_shared_max(struct dma_resv *obj) {}
+static inline void dma_resv_reset_max_fences(struct dma_resv *obj) {}
 #endif
 
 /**
@@ -454,17 +458,18 @@ static inline struct ww_acquire_ctx *dma_resv_locking_ctx(struct dma_resv *obj)
  */
 static inline void dma_resv_unlock(struct dma_resv *obj)
 {
-	dma_resv_reset_shared_max(obj);
+	dma_resv_reset_max_fences(obj);
 	ww_mutex_unlock(&obj->lock);
 }
 
 void dma_resv_init(struct dma_resv *obj);
 void dma_resv_fini(struct dma_resv *obj);
 int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences);
-void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence);
+void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence,
+			enum dma_resv_usage usage);
 void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context,
-			     struct dma_fence *fence);
-void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence);
+			     struct dma_fence *fence,
+			     enum dma_resv_usage usage);
 int dma_resv_get_fences(struct dma_resv *obj, enum dma_resv_usage usage,
 			unsigned int *num_fences, struct dma_fence ***fences);
 int dma_resv_get_singleton(struct dma_resv *obj, enum dma_resv_usage usage,