From: Honglei Huang <honghuan@amd.com>

Add interval tree support for efficient lookup of affected userptr
ranges during MMU notifier callbacks.

add:
- Include linux/interval_tree.h
- discard_invalid_ranges() function that uses interval tree to
  identify and mark ranges affected by a given invalidation event

Signed-off-by: Honglei Huang <honghuan@amd.com>
---
 .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index a32b46355..6fe4ed22c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -25,6 +25,7 @@
 #include <linux/pagemap.h>
 #include <linux/sched/mm.h>
 #include <linux/sched/task.h>
+#include <linux/interval_tree.h>
 #include <drm/ttm/ttm_tt.h>
 
 #include <drm/drm_exec.h>
@@ -1122,6 +1123,26 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr,
 	return ret;
 }
 
+static bool discard_invalid_ranges(struct kgd_mem *mem,
+				unsigned long inv_start, unsigned long inv_end)
+{
+	struct interval_tree_node *node;
+	struct user_range_info *range_info;
+	bool any_invalid = false;
+
+	for (node = interval_tree_iter_first(&mem->user_ranges_itree, inv_start, inv_end - 1);
+		 node;
+		 node = interval_tree_iter_next(node, inv_start, inv_end - 1)) {
+		range_info = container_of(node, struct user_range_info, it_node);
+
+		range_info->valid = false;
+		any_invalid = true;
+		pr_debug("Range [0x%llx-0x%llx) marked invalid\n",
+			 range_info->start, range_info->start + range_info->size);
+	}
+	return any_invalid;
+}
+
 /* Reserving a BO and its page table BOs must happen atomically to
  * avoid deadlocks. Some operations update multiple VMs at once. Track
  * all the reservation info in a context structure. Optionally a sync
-- 
2.34.1