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From: SeongJae Park <sj@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: SeongJae Park <sj@kernel.org>,
	damon@lists.linux.dev, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org
Subject: [PATCH 2/3] mm/damon/core: use time_before() for next_apply_sis
Date: Sat,  7 Mar 2026 11:49:13 -0800	[thread overview]
Message-ID: <20260307194915.203169-3-sj@kernel.org> (raw)
In-Reply-To: <20260307194915.203169-1-sj@kernel.org>

damon_ctx->passed_sample_intervals and damos->next_apply_sis are
unsigned long, and compared via normal comparison operators.  It is
unsafe from overflow.  Use time_before(), which is safe from overflow
when correctly used, instead.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index c4c30824465ee..4ede733a94cc0 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -2095,7 +2095,7 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
 	damon_for_each_scheme(s, c) {
 		struct damos_quota *quota = &s->quota;
 
-		if (c->passed_sample_intervals < s->next_apply_sis)
+		if (time_before(c->passed_sample_intervals, s->next_apply_sis))
 			continue;
 
 		if (!s->wmarks.activated)
@@ -2453,7 +2453,7 @@ static void kdamond_apply_schemes(struct damon_ctx *c)
 	bool has_schemes_to_apply = false;
 
 	damon_for_each_scheme(s, c) {
-		if (c->passed_sample_intervals < s->next_apply_sis)
+		if (time_before(c->passed_sample_intervals, s->next_apply_sis))
 			continue;
 
 		if (!s->wmarks.activated)
@@ -2477,7 +2477,7 @@ static void kdamond_apply_schemes(struct damon_ctx *c)
 	}
 
 	damon_for_each_scheme(s, c) {
-		if (c->passed_sample_intervals < s->next_apply_sis)
+		if (time_before(c->passed_sample_intervals, s->next_apply_sis))
 			continue;
 		damos_walk_complete(c, s);
 		damos_set_next_apply_sis(s, c);
-- 
2.47.3

  parent reply	other threads:[~2026-03-07 19:49 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-07 19:49 [PATCH 0/3] mm/damon/core: make passed_sample_intervals comparisons overflow-safe SeongJae Park
2026-03-07 19:49 ` [PATCH 1/3] mm/damon/core: remove damos_set_next_apply_sis() duplicates SeongJae Park
2026-03-07 19:49 ` SeongJae Park [this message]
2026-03-07 19:49 ` [PATCH 3/3] mm/damon/core: use time_after_eq() in kdamond_fn() SeongJae Park

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