drm/amd/display: Optimize remove_duplicates() from O(N^2) to O(N)

Replace the previous O(N^2) implementation of remove_duplicates() with
a O(N) version using a fast/slow pointer approach. The new version
keeps only the first occurrence of each element and compacts the array
in place, improving efficiency without changing functionality.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_pmo/dml2_pmo_dcn3.c b/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_pmo/dml2_pmo_dcn3.c
index e763c8e45da8174e016b0b9a9bf692f24616a108..1b9579a32ff2846a29bb8175f0a05b0d2bfa0483 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_pmo/dml2_pmo_dcn3.c
+++ b/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_pmo/dml2_pmo_dcn3.c
@@ -48,18 +48,19 @@ static void set_reserved_time_on_all_planes_with_stream_index(struct display_con
 
 static void remove_duplicates(double *list_a, int *list_a_size)
 {
-       int cur_element = 0;
-       // For all elements b[i] in list_b[]
-       while (cur_element < *list_a_size - 1) {
-               if (list_a[cur_element] == list_a[cur_element + 1]) {
-                       for (int j = cur_element + 1; j < *list_a_size - 1; j++) {
-                               list_a[j] = list_a[j + 1];
-                       }
-                       *list_a_size = *list_a_size - 1;
-               } else {
-                       cur_element++;
+       int j = 0;
+
+       if (*list_a_size == 0)
+               return;
+
+       for (int i = 1; i < *list_a_size; i++) {
+               if (list_a[j] != list_a[i]) {
+                       j++;
+                       list_a[j] = list_a[i];
                }
        }
+
+       *list_a_size = j + 1;
 }
 
 static bool increase_mpc_combine_factor(unsigned int *mpc_combine_factor, unsigned int limit)