From 7b57976da48e60b66fdbb9e97f5711b5382a49d7 Mon Sep 17 00:00:00 2001
From: Akinobu Mita <akinobu.mita@gmail.com>
Date: Wed, 12 Jun 2013 14:05:08 -0700
Subject: [PATCH] frontswap: fix incorrect zeroing and allocation size for
frontswap_map
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 <akinobu.mita@gmail.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
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 538367ef13727..1b24bdcb31974 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 6c340d908b274..746af55b8455c 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))) {
--
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