From: Yu Kuai yukuai3@huawei.com
[ Upstream commit 8d6bbaada2e0a65f9012ac4c2506460160e7237a ]
There is a problem found by code review in tg_with_in_bps_limit() that 'bps_limit * jiffy_elapsed_rnd' might overflow. Fix the problem by calling mul_u64_u64_div_u64() instead.
Signed-off-by: Yu Kuai yukuai3@huawei.com Acked-by: Tejun Heo tj@kernel.org Link: https://lore.kernel.org/r/20220829022240.3348319-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-throttle.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index c53a254171a2..c526fdd0a7b9 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -944,7 +944,7 @@ static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio, u64 bps_limit, unsigned long *wait) { bool rw = bio_data_dir(bio); - u64 bytes_allowed, extra_bytes, tmp; + u64 bytes_allowed, extra_bytes; unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; unsigned int bio_size = throtl_bio_data_size(bio);
@@ -961,10 +961,8 @@ static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio, jiffy_elapsed_rnd = tg->td->throtl_slice;
jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice); - - tmp = bps_limit * jiffy_elapsed_rnd; - do_div(tmp, HZ); - bytes_allowed = tmp; + bytes_allowed = mul_u64_u64_div_u64(bps_limit, (u64)jiffy_elapsed_rnd, + (u64)HZ);
if (tg->bytes_disp[rw] + bio_size <= bytes_allowed) { if (wait)