path: root/mm/swapfile.c
diff options
authorAkinobu Mita <>2013-06-12 14:05:08 -0700
committerLinus Torvalds <>2013-06-12 16:29:46 -0700
commit7b57976da48e60b66fdbb9e97f5711b5382a49d7 (patch)
tree4295f72436564c0bbb0521cbf486fd6907aa5e18 /mm/swapfile.c
parent736f3203a06eafd0944103775a98584082744c6b (diff)
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 <> Cc: Konrad Rzeszutek Wilk <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'mm/swapfile.c')
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 6c340d908b27..746af55b8455 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))) {