[PATCH 3/3] mm/damon/core: use time_after_eq() in kdamond_fn()

[SeongJae Park <sj@kernel.org>]

damon_ctx->passed_sample_intervals and damon_ctx->next_*_sis are
unsigned long.  Those are compared in kdamond_fn() using normal
comparison operators.  It is unsafe from overflow.  Use time_after_eq(),
which is safe from overflows when correctly used, instead.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 4ede733a94cc0..cd2d7a8e3fe92 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -2915,7 +2915,8 @@ static int kdamond_fn(void *data)
 		if (ctx->ops.check_accesses)
 			max_nr_accesses = ctx->ops.check_accesses(ctx);
 
-		if (ctx->passed_sample_intervals >= next_aggregation_sis) {
+		if (time_after_eq(ctx->passed_sample_intervals,
+					next_aggregation_sis)) {
 			kdamond_merge_regions(ctx,
 					max_nr_accesses / 10,
 					sz_limit);
@@ -2935,10 +2936,12 @@ static int kdamond_fn(void *data)
 
 		sample_interval = ctx->attrs.sample_interval ?
 			ctx->attrs.sample_interval : 1;
-		if (ctx->passed_sample_intervals >= next_aggregation_sis) {
+		if (time_after_eq(ctx->passed_sample_intervals,
+					next_aggregation_sis)) {
 			if (ctx->attrs.intervals_goal.aggrs &&
-					ctx->passed_sample_intervals >=
-					ctx->next_intervals_tune_sis) {
+					time_after_eq(
+						ctx->passed_sample_intervals,
+						ctx->next_intervals_tune_sis)) {
 				/*
 				 * ctx->next_aggregation_sis might be updated
 				 * from kdamond_call().  In the case,
@@ -2972,7 +2975,8 @@ static int kdamond_fn(void *data)
 			kdamond_split_regions(ctx);
 		}
 
-		if (ctx->passed_sample_intervals >= next_ops_update_sis) {
+		if (time_after_eq(ctx->passed_sample_intervals,
+					next_ops_update_sis)) {
 			ctx->next_ops_update_sis = next_ops_update_sis +
 				ctx->attrs.ops_update_interval /
 				sample_interval;
-- 
2.47.3