lib/interval_tree: fast overlap detection

Allow interval trees to quickly check for overlaps to avoid unnecesary
tree lookups in interval_tree_iter_first().

As of this patch, all interval tree flavors will require using a
'rb_root_cached' such that we can have the leftmost node easily
available.  While most users will make use of this feature, those with
special functions (in addition to the generic insert, delete, search
calls) will avoid using the cached option as they can do funky things
with insertions -- for example, vma_interval_tree_insert_after().

[[email protected]: fix deadlock from typo vm_lock_anon_vma()]
  Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Davidlohr Bueso <[email protected]>
Signed-off-by: Jérôme Glisse <[email protected]>
Acked-by: Christian König <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Doug Ledford <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: Christian Benvenuti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 6b1343e5541d..b9a5a77eedaf 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -2475,7 +2475,7 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 	u64 flags;
 	uint64_t init_pde_value = 0;
 
-	vm->va = RB_ROOT;
+	vm->va = RB_ROOT_CACHED;
 	vm->client_id = atomic64_inc_return(&adev->vm_manager.client_counter);
 	for (i = 0; i < AMDGPU_MAX_VMHUBS; i++)
 		vm->reserved_vmid[i] = NULL;
@@ -2596,10 +2596,11 @@ void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
 
 	amd_sched_entity_fini(vm->entity.sched, &vm->entity);
 
-	if (!RB_EMPTY_ROOT(&vm->va)) {
+	if (!RB_EMPTY_ROOT(&vm->va.rb_root)) {
 		dev_err(adev->dev, "still active bo inside vm\n");
 	}
-	rbtree_postorder_for_each_entry_safe(mapping, tmp, &vm->va, rb) {
+	rbtree_postorder_for_each_entry_safe(mapping, tmp,
+					     &vm->va.rb_root, rb) {
 		list_del(&mapping->list);
 		amdgpu_vm_it_remove(mapping, &vm->va);
 		kfree(mapping);