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Subject[PATCH,1/2] genhd: avoid overflow of sectors in disk_stats
Date
From: "huijin.park" <huijin.park@samsung.com>

This patch changes the 'sectors' type to an u64.
In 32 bit system, the 'sectors' can accumulate up to about 2TiB.
If a 32 bit system makes i/o over 2TiB while running,
the 'sectors' will overflow.
As a result, the part_stat_read(sectors), the diskstats in proc and
the (lifetime|session)_write_kbytes in sysfs return invalid statistic.

Signed-off-by: huijin.park <huijin.park@samsung.com>
---
block/genhd.c | 6 +++---
include/linux/genhd.h | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 0145bcb..7518dcd 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1343,10 +1343,10 @@ static int diskstats_show(struct seq_file *seqf, void *v)
part_stat_unlock();
part_in_flight(gp->queue, hd, inflight);
seq_printf(seqf, "%4d %7d %s "
- "%lu %lu %lu %u "
- "%lu %lu %lu %u "
+ "%lu %lu %llu %u "
+ "%lu %lu %llu %u "
"%u %u %u "
- "%lu %lu %lu %u\n",
+ "%lu %lu %llu %u\n",
MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
disk_name(gp, hd->partno, buf),
part_stat_read(hd, ios[STAT_READ]),
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 0c5ee17..5bf86f9 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -84,7 +84,7 @@ struct partition {

struct disk_stats {
u64 nsecs[NR_STAT_GROUPS];
- unsigned long sectors[NR_STAT_GROUPS];
+ u64 sectors[NR_STAT_GROUPS];
unsigned long ios[NR_STAT_GROUPS];
unsigned long merges[NR_STAT_GROUPS];
unsigned long io_ticks;
--
1.7.9.5
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