From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB2B6C43219 for ; Thu, 13 Oct 2022 00:18:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230027AbiJMASP (ORCPT ); Wed, 12 Oct 2022 20:18:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38460 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229966AbiJMARn (ORCPT ); Wed, 12 Oct 2022 20:17:43 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45D0D18C94D; Wed, 12 Oct 2022 17:17:02 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id F017DB81CC1; Thu, 13 Oct 2022 00:16:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3C50C43470; Thu, 13 Oct 2022 00:16:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1665620205; bh=HiDHAOPSQv6P3nE8r2l5k+CLpdCGeWChgEX9BNsMegY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a5CIkR2Mitb82E4vl9gQn9/fzdho6eDrA8slnHZK4A1fy7fpjYxQypRqMIvt3z4Ek PcbptdG+PEXiiBOJ0BWjd+I4sjSXTdx5t6hD5gjQ/nNTtAU1zW6rjReIWeneiGeEMN JIpDs1Zf0KYerQZyrv5H9LcNWlLdeoYrg+/R0XvnHqgRCD6YsEQC4vEFGzEeqfWHbK JmeM9BbXWbJgvNm6Qwvtgg3qzlovjLnE3xhyBYjT0PaDcDfsbRXACMeeMlMK3OySdS Pk89ASq0Ns9YeADXVve37ZNMpTTTeVrEUWS9YwZe+yGVLUm2o5e7TNXUWQTChZNmvZ /Q8Syde+cmF9w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Yu Kuai , Tejun Heo , Jens Axboe , Sasha Levin , cgroups@vger.kernel.org, linux-block@vger.kernel.org Subject: [PATCH AUTOSEL 6.0 19/67] blk-throttle: prevent overflow while calculating wait time Date: Wed, 12 Oct 2022 20:15:00 -0400 Message-Id: <20221013001554.1892206-19-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221013001554.1892206-1-sashal@kernel.org> References: <20221013001554.1892206-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Yu Kuai [ 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 Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20220829022240.3348319-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- 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 9f5fe62afff9..55a764e5ba61 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) -- 2.35.1