From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx130.postini.com [74.125.245.130]) by kanga.kvack.org (Postfix) with SMTP id 99C766B0032 for ; Sat, 1 Jun 2013 19:53:28 -0400 (EDT) Received: by mail-pd0-f170.google.com with SMTP id x10so3989969pdj.1 for ; Sat, 01 Jun 2013 16:53:27 -0700 (PDT) From: Akinobu Mita 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> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org Cc: Akinobu Mita , Konrad Rzeszutek Wilk 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org