path: root/block
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authorMartin K. Petersen <martin.petersen@oracle.com>2010-03-15 12:46:51 +0100
committerJens Axboe <jens.axboe@oracle.com>2010-03-15 12:47:59 +0100
commit2cda2728aa1c8c006418a24f867b25e5eb7a32e2 (patch)
treec23ec7c38d74237646c5453d96bfbbea4cadfee7 /block
parentvfs: improve writeback_inodes_wb() (diff)
block: Fix overrun in lcm() and move it to lib
lcm() was defined to take integer-sized arguments. The supplied arguments are multiplied, however, causing us to overflow given sufficiently large input. That in turn led to incorrect optimal I/O size reporting in some cases (RAID over RAID). Switch lcm() over to unsigned long similar to gcd() and move the function from blk-settings.c to lib. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
1 files changed, 1 insertions, 10 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 31e7a9375c13..4c4700dca56a 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -8,6 +8,7 @@
#include <linux/blkdev.h>
#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
#include <linux/gcd.h>
+#include <linux/lcm.h>
#include <linux/jiffies.h>
#include "blk.h"
@@ -461,16 +462,6 @@ void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
-static unsigned int lcm(unsigned int a, unsigned int b)
- if (a && b)
- return (a * b) / gcd(a, b);
- else if (b)
- return b;
- return a;
* blk_stack_limits - adjust queue_limits for stacked devices
* @t: the stacking driver limits (top device)