diff options
| author | Yu Kuai <yukuai3@huawei.com> | 2022-08-29 10:22:38 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-10-24 09:58:25 +0200 |
| commit | cc6f0855bf8d9b729df28ff443ced7350c380dbd (patch) | |
| tree | 508f9c961f1b92ec091b7f8a5cf7ad383d022334 | |
| parent | fb5f569bcda8f87bd47d8030bfae343d757fa3ea (diff) | |
blk-throttle: prevent overflow while calculating wait time
[ 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>
| -rw-r--r-- | block/blk-throttle.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 387783980024..acdd85a07f92 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -806,7 +806,7 @@ 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); @@ -824,10 +824,8 @@ 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) |