diff --git a/drivers/gpu/nvgpu/common/mm/bitmap_allocator.c b/drivers/gpu/nvgpu/common/mm/bitmap_allocator.c
index e5b9b3785..396f04724 100644
--- a/drivers/gpu/nvgpu/common/mm/bitmap_allocator.c
+++ b/drivers/gpu/nvgpu/common/mm/bitmap_allocator.c
@@ -275,7 +275,8 @@ static void nvgpu_bitmap_free(struct nvgpu_allocator *na, u64 addr)
 	alloc_lock(na);
 
 	if (a->flags & GPU_ALLOC_NO_ALLOC_PAGE) {
-		WARN(1, "Using wrong free for NO_ALLOC_PAGE bitmap allocator");
+		(void) WARN(1,
+			"Using wrong free for NO_ALLOC_PAGE bitmap allocator");
 		goto done;
 	}
 
diff --git a/drivers/gpu/nvgpu/common/mm/buddy_allocator.c b/drivers/gpu/nvgpu/common/mm/buddy_allocator.c
index 0ce9ae8a9..a7121c97a 100644
--- a/drivers/gpu/nvgpu/common/mm/buddy_allocator.c
+++ b/drivers/gpu/nvgpu/common/mm/buddy_allocator.c
@@ -308,7 +308,7 @@ static void nvgpu_buddy_allocator_destroy(struct nvgpu_allocator *na)
 	while (node) {
 		bud = nvgpu_buddy_from_rbtree_node(node);
 
-		balloc_free_buddy(a, bud->start);
+		(void) balloc_free_buddy(a, bud->start);
 		balloc_blist_add(a, bud);
 		balloc_coalesce(a, bud);
 
@@ -821,7 +821,7 @@ err_and_cleanup:
 						nvgpu_buddy, buddy_entry);
 
 		balloc_buddy_list_do_rem(a, bud);
-		balloc_free_buddy(a, bud->start);
+		(void) balloc_free_buddy(a, bud->start);
 		nvgpu_kmem_cache_free(a->buddy_cache, bud);
 	}
 
@@ -839,7 +839,7 @@ static void balloc_do_free_fixed(struct nvgpu_buddy_allocator *a,
 				       buddy_entry);
 		balloc_buddy_list_do_rem(a, bud);
 
-		balloc_free_buddy(a, bud->start);
+		(void) balloc_free_buddy(a, bud->start);
 		balloc_blist_add(a, bud);
 		a->bytes_freed += balloc_order_to_len(a, bud->order);
 
diff --git a/drivers/gpu/nvgpu/common/mm/gmmu.c b/drivers/gpu/nvgpu/common/mm/gmmu.c
index afbad75c6..a25dd4bb3 100644
--- a/drivers/gpu/nvgpu/common/mm/gmmu.c
+++ b/drivers/gpu/nvgpu/common/mm/gmmu.c
@@ -787,11 +787,7 @@ void gk20a_locked_gmmu_unmap(struct vm_gk20a *vm,
 	};
 
 	if (va_allocated) {
-		err = __nvgpu_vm_free_va(vm, vaddr, pgsz_idx);
-		if (err) {
-			nvgpu_err(g, "failed to free va");
-			return;
-		}
+		__nvgpu_vm_free_va(vm, vaddr, pgsz_idx);
 	}
 
 	/* unmap here needs to know the page size we assigned at mapping */
diff --git a/drivers/gpu/nvgpu/common/mm/page_allocator.c b/drivers/gpu/nvgpu/common/mm/page_allocator.c
index 35c7e1201..951aefa8a 100644
--- a/drivers/gpu/nvgpu/common/mm/page_allocator.c
+++ b/drivers/gpu/nvgpu/common/mm/page_allocator.c
@@ -246,14 +246,13 @@ static void nvgpu_page_alloc_free_pages(struct nvgpu_page_allocator *a,
 	nvgpu_kmem_cache_free(a->alloc_cache, alloc);
 }
 
-static int insert_page_alloc(struct nvgpu_page_allocator *a,
+static void insert_page_alloc(struct nvgpu_page_allocator *a,
 			     struct nvgpu_page_alloc *alloc)
 {
 	alloc->tree_entry.key_start = alloc->base;
 	alloc->tree_entry.key_end = alloc->base + alloc->length;
 
 	nvgpu_rbtree_insert(&alloc->tree_entry, &a->allocs);
-	return 0;
 }
 
 static struct nvgpu_page_alloc *find_page_alloc(
@@ -368,7 +367,7 @@ static int do_slab_alloc(struct nvgpu_page_allocator *a,
 					  slab_page->nr_objects,
 					  0, 1, 0);
 	if (offs >= slab_page->nr_objects) {
-		WARN(1, "Empty/partial slab with no free objects?");
+		(void) WARN(1, "Empty/partial slab with no free objects?");
 
 		/* Add the buggy page to the full list... This isn't ideal. */
 		add_slab_page_to_full(slab, slab_page);
@@ -767,7 +766,8 @@ static struct nvgpu_page_alloc *nvgpu_alloc_pages_fixed(
 	alloc->sgt.ops = &page_alloc_sgl_ops;
 	alloc->base = nvgpu_alloc_fixed(&a->source_allocator, base, length, 0);
 	if (alloc->base == 0ULL) {
-		WARN(1, "nvgpu: failed to fixed alloc pages @ 0x%010llx", base);
+		(void) WARN(1, "nvgpu: failed to fixed alloc pages @ 0x%010llx",
+			base);
 		goto fail;
 	}
 
diff --git a/drivers/gpu/nvgpu/common/mm/pd_cache.c b/drivers/gpu/nvgpu/common/mm/pd_cache.c
index d9dc3db06..4fba7d990 100644
--- a/drivers/gpu/nvgpu/common/mm/pd_cache.c
+++ b/drivers/gpu/nvgpu/common/mm/pd_cache.c
@@ -441,7 +441,7 @@ static void nvgpu_pd_cache_free(struct gk20a *g, struct nvgpu_pd_cache *cache,
 
 	pentry = nvgpu_pd_cache_look_up(g, cache, pd);
 	if (pentry == NULL) {
-		WARN(1, "Attempting to free non-existent pd");
+		(void) WARN(1, "Attempting to free non-existent pd");
 		return;
 	}
 
diff --git a/drivers/gpu/nvgpu/common/mm/vm.c b/drivers/gpu/nvgpu/common/mm/vm.c
index 7f0b3d104..8888d6f3f 100644
--- a/drivers/gpu/nvgpu/common/mm/vm.c
+++ b/drivers/gpu/nvgpu/common/mm/vm.c
@@ -160,13 +160,11 @@ u64 __nvgpu_vm_alloc_va(struct vm_gk20a *vm, u64 size, u32 pgsz_idx)
 	return addr;
 }
 
-int __nvgpu_vm_free_va(struct vm_gk20a *vm, u64 addr, u32 pgsz_idx)
+void __nvgpu_vm_free_va(struct vm_gk20a *vm, u64 addr, u32 pgsz_idx)
 {
 	struct nvgpu_allocator *vma = vm->vma[pgsz_idx];
 
 	nvgpu_free(vma, addr);
-
-	return 0;
 }
 
 void nvgpu_vm_mapping_batch_start(struct vm_gk20a_mapping_batch *mapping_batch)
@@ -1175,12 +1173,17 @@ static int nvgpu_vm_unmap_sync_buffer(struct vm_gk20a *vm,
 	struct nvgpu_timeout timeout;
 	int ret = 0;
 
-	nvgpu_mutex_release(&vm->update_gmmu_lock);
-
 	/*
 	 * 100ms timer.
 	 */
-	nvgpu_timeout_init(vm->mm->g, &timeout, 100, NVGPU_TIMER_CPU_TIMER);
+	ret = nvgpu_timeout_init(vm->mm->g, &timeout, 100,
+		NVGPU_TIMER_CPU_TIMER);
+	if (ret != 0) {
+		nvgpu_err(vm->mm->g, "timeout_init failed (%d)", ret);
+		return ret;
+	}
+
+	nvgpu_mutex_release(&vm->update_gmmu_lock);
 
 	do {
 		if (nvgpu_atomic_read(&mapped_buffer->ref.refcount) == 1) {
diff --git a/drivers/gpu/nvgpu/include/nvgpu/kref.h b/drivers/gpu/nvgpu/include/nvgpu/kref.h
index 486040e81..460eb4b38 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/kref.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/kref.h
@@ -57,12 +57,30 @@ static inline void nvgpu_ref_get(struct nvgpu_ref *ref)
  * @release: pointer to the function that would be invoked to clean up the
  *	object when the reference count becomes zero, i.e. the last
  *	reference corresponding to this object is removed.
+ */
+static inline void nvgpu_ref_put(struct nvgpu_ref *ref,
+		void (*release)(struct nvgpu_ref *r))
+{
+	if (nvgpu_atomic_sub_and_test(1, &ref->refcount)) {
+		if (release != NULL) {
+			release(ref);
+		}
+	}
+}
+
+/*
+ * Decrement reference count for the object, call release() if it becomes
+ * zero and return the status of the removal.
+ * @ref: the nvgpu_ref object
+ * @release: pointer to the function that would be invoked to clean up the
+ *	object when the reference count becomes zero, i.e. the last
+ *	reference corresponding to this object is removed.
  * Return 1 if object was removed, otherwise return 0. The user should not
  * make any assumptions about the status of the object in the memory when
  * the function returns 0 and should only use it to know that there are no
  * further references to this object.
  */
-static inline int nvgpu_ref_put(struct nvgpu_ref *ref,
+static inline int nvgpu_ref_put_return(struct nvgpu_ref *ref,
 		void (*release)(struct nvgpu_ref *r))
 {
 	if (nvgpu_atomic_sub_and_test(1, &ref->refcount)) {
diff --git a/drivers/gpu/nvgpu/include/nvgpu/vm.h b/drivers/gpu/nvgpu/include/nvgpu/vm.h
index 667497174..cb9f06d5a 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/vm.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/vm.h
@@ -323,7 +323,7 @@ struct vm_gk20a *nvgpu_vm_init(struct gk20a *g,
  */
 u64 __nvgpu_vm_alloc_va(struct vm_gk20a *vm, u64 size,
 				u32 pgsz_idx);
-int __nvgpu_vm_free_va(struct vm_gk20a *vm, u64 addr,
+void __nvgpu_vm_free_va(struct vm_gk20a *vm, u64 addr,
 				u32 pgsz_idx);
 
 #endif /* NVGPU_VM_H */
diff --git a/drivers/gpu/nvgpu/vgpu/mm_vgpu.c b/drivers/gpu/nvgpu/vgpu/mm_vgpu.c
index ae35cafc5..cae54475a 100644
--- a/drivers/gpu/nvgpu/vgpu/mm_vgpu.c
+++ b/drivers/gpu/nvgpu/vgpu/mm_vgpu.c
@@ -107,9 +107,7 @@ void vgpu_locked_gmmu_unmap(struct vm_gk20a *vm,
 		nvgpu_err(g, "failed to update gmmu ptes on unmap");
 
 	if (va_allocated) {
-		err = __nvgpu_vm_free_va(vm, vaddr, pgsz_idx);
-		if (err)
-			nvgpu_err(g, "failed to free va");
+		__nvgpu_vm_free_va(vm, vaddr, pgsz_idx);
 	}
 	/* TLB invalidate handled on server side */
 }