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.

Link: http://lkml.kernel.org/r/1470929182-101413-1-git-send-email-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kuthonuzo Luruo <kuthonuzo.luruo@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
index b6728a33a4aca104fde8022b90fdf2df5630af31..baabaad4a4aaa89bb13fc691cf5df58af46c8b3b 100644 (file)
--- 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;