From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753376Ab3FAXxb (ORCPT ); Sat, 1 Jun 2013 19:53:31 -0400 Received: from mail-pb0-f51.google.com ([209.85.160.51]:58083 "EHLO mail-pb0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751161Ab3FAXx2 (ORCPT ); Sat, 1 Jun 2013 19:53:28 -0400 From: Akinobu Mita To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org Cc: Akinobu Mita , Konrad Rzeszutek Wilk Subject: [PATCH] frontswap: fix incorrect zeroing and allocation size for frontswap_map Date: Sun, 2 Jun 2013 08:52:57 +0900 Message-Id: <1370130777-6707-1-git-send-email-akinobu.mita@gmail.com> X-Mailer: git-send-email 1.8.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The bitmap accessed by bitops must have enough size to hold the required numbers of bits rounded up to a multiple of BITS_PER_LONG. And the bitmap must not be zeroed by memset() if the number of bits cleared is not a multiple of BITS_PER_LONG. This fixes incorrect zeroing and allocation size for frontswap_map. The incorrect zeroing part doesn't cause any problem because frontswap_map is freed just after zeroing. But the wrongly calculated allocation size may cause the problem. For 32bit systems, the allocation size of frontswap_map is about twice as large as required size. For 64bit systems, the allocation size is smaller than requeired if the number of bits is not a multiple of BITS_PER_LONG. Signed-off-by: Akinobu Mita Cc: Konrad Rzeszutek Wilk --- mm/frontswap.c | 2 +- mm/swapfile.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/frontswap.c b/mm/frontswap.c index 538367e..1b24bdc 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -319,7 +319,7 @@ void __frontswap_invalidate_area(unsigned type) return; frontswap_ops->invalidate_area(type); atomic_set(&sis->frontswap_pages, 0); - memset(sis->frontswap_map, 0, sis->max / sizeof(long)); + bitmap_zero(sis->frontswap_map, sis->max); } clear_bit(type, need_init); } diff --git a/mm/swapfile.c b/mm/swapfile.c index 6c340d9..746af55b 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2116,7 +2116,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) } /* frontswap enabled? set up bit-per-page map for frontswap */ if (frontswap_enabled) - frontswap_map = vzalloc(maxpages / sizeof(long)); + frontswap_map = vzalloc(BITS_TO_LONGS(maxpages) * sizeof(long)); if (p->bdev) { if (blk_queue_nonrot(bdev_get_queue(p->bdev))) { -- 1.8.1.4