linux-kernel - [PATCH] kasan: remove the unnecessary WARN

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Date:	Thu, 11 Aug 2016 17:26:22 +0200
From:	Alexander Potapenko <glider@...gle.com>
To:	dvyukov@...gle.com, kcc@...gle.com, aryabinin@...tuozzo.com,
	adech.fo@...il.com, cl@...ux.com, akpm@...ux-foundation.org,
	rostedt@...dmis.org, js1304@...il.com, iamjoonsoo.kim@....com,
	kuthonuzo.luruo@....com
Cc:	kasan-dev@...glegroups.com, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: [PATCH] kasan: remove the unnecessary WARN_ONCE from quarantine.c

It's quite unlikely that the user will so little memory that the
per-CPU quarantines won't fit into the given fraction of the available
memory. Even in that case he won't be able to do anything with the
information given in the warning.

Signed-off-by: Alexander Potapenko <glider@...gle.com>
---
 mm/kasan/quarantine.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
index b6728a3..baabaad 100644
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -217,11 +217,8 @@ void quarantine_reduce(void)
 	new_quarantine_size = (READ_ONCE(totalram_pages) << PAGE_SHIFT) /
 		QUARANTINE_FRACTION;
 	percpu_quarantines = QUARANTINE_PERCPU_SIZE * num_online_cpus();
-	if (WARN_ONCE(new_quarantine_size < percpu_quarantines,
-		"Too little memory, disabling global KASAN quarantine.\n"))
-		new_quarantine_size = 0;
-	else
-		new_quarantine_size -= percpu_quarantines;
+	new_quarantine_size = (new_quarantine_size < percpu_quarantines) ?
+		0 : new_quarantine_size - percpu_quarantines;
 	WRITE_ONCE(quarantine_size, new_quarantine_size);
 
 	last = global_quarantine.head;
-- 
2.8.0.rc3.226.g39d4020