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[3/3] mm/page-writeback.c: improve arithmetic divisions

Message ID 20200102081442.8273-4-wenyang@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series use div64_ul() instead of div_u64() if the divisor is unsigned long | expand

Commit Message

Wen Yang Jan. 2, 2020, 8:14 a.m. UTC 
Use div64_ul() instead of do_div() if the divisor is unsigned long,
to avoid truncation to 32-bit on 64-bit platforms.

Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/page-writeback.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index c74c6bd..2caf780 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1102,7 +1102,7 @@  static void wb_update_write_bandwidth(struct bdi_writeback *wb,
 	bw = written - min(written, wb->written_stamp);
 	bw *= HZ;
 	if (unlikely(elapsed > period)) {
-		do_div(bw, elapsed);
+		bw = div64_ul(bw, elapsed);
 		avg = bw;
 		goto out;
 	}