[RFC PATCH v1.1 1/7] mm/damon/core: remove obsolete comment for nr_to_bp() divide-by-zero

[SJ Park <sj@kernel.org>]

damon_nr_accesses_to_accesses_bp() warns it can trigger division-by-zero
when the aggregation interval is zero.  Commit 35d4a3cf70a8
("mm/damon/ops-common: handle extreme intervals in damon_hot_score()")
modified damon_nr_samples_per_aggr() to always return non-zero.  Hence
no division-by-zero of the note can happen.  Remove the obsolete comment
on the function and its test code.  Also remove the unnecessary guard
code in the test.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/core.c             |  8 +-------
 mm/damon/tests/core-kunit.h | 12 ------------
 2 files changed, 1 insertion(+), 19 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 390e00b3685ef..a15005db82899 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -883,13 +883,7 @@ static unsigned int damon_accesses_bp_to_nr_accesses(
 	return accesses_bp * damon_max_nr_accesses(attrs) / 10000;
 }
 
-/*
- * Convert nr_accesses to access ratio in bp (per 10,000).
- *
- * Callers should ensure attrs.aggr_interval is not zero, like
- * damon_update_monitoring_results() does .  Otherwise, divide-by-zero would
- * happen.
- */
+/* Convert nr_accesses to access ratio in bp (per 10,000) */
 static unsigned int damon_nr_accesses_to_accesses_bp(
 		unsigned int nr_accesses, struct damon_attrs *attrs)
 {
diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 0124f83b39b83..224a3ecaa0701 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -582,18 +582,6 @@ static void damon_test_nr_accesses_to_accesses_bp(struct kunit *test)
 		.aggr_interval = ((unsigned long)UINT_MAX + 1) * 10
 	};
 
-	/*
-	 * In some cases such as 32bit architectures where UINT_MAX is
-	 * ULONG_MAX, attrs.aggr_interval becomes zero.  Calling
-	 * damon_nr_accesses_to_accesses_bp() in the case will cause
-	 * divide-by-zero.  Such case is prohibited in normal execution since
-	 * the caution is documented on the comment for the function, and
-	 * damon_update_monitoring_results() does the check.  Skip the test in
-	 * the case.
-	 */
-	if (!attrs.aggr_interval)
-		kunit_skip(test, "aggr_interval is zero.");
-
 	KUNIT_EXPECT_EQ(test, damon_nr_accesses_to_accesses_bp(123, &attrs), 0);
 }
 
-- 
2.47.3