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 3210AC433FE for ; Thu, 13 Oct 2022 00:32:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231726AbiJMAcp (ORCPT ); Wed, 12 Oct 2022 20:32:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49528 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231879AbiJMA3X (ORCPT ); Wed, 12 Oct 2022 20:29:23 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0EFC511E47C; Wed, 12 Oct 2022 17:26:30 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 7AC1361646; Thu, 13 Oct 2022 00:24:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D5DAC43142; Thu, 13 Oct 2022 00:24:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1665620651; bh=p6GiSY8fKFEwVLEYaOs1ega9J3UWlailRKtYivPY8dg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ralkKVeHDCFg1GzFTTPBFCW/lnC/sQw4/tbmuAuLziiHeCg18QFyjuqgAi6rKzRsI 9wGuznO3f88WlF1zMeQ/BGatOANV0iHmlwOZz0nlo97iy6GXeguz595aSAmyaSP5Yo Nt7XB/jW2MpCQeXZTTLM5TWk/jNmw+SG2FSDsZYemdZz4pOaPc0oqnTV+QhEQ1ffUy N6GsNd1r35kBVapSXUjYnpcpKoh4klskB9TuS+qD1zQl4QMdg6rRSHTd9IqN7UDgNr 29F6uvnQvClPULo2C57XYJuY+yUR/t7x4cmNyO0qWI10svancil/kaHzKAouMSW7oe wKXHqJT4LxaTQ== 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 5.10 13/33] blk-throttle: prevent overflow while calculating wait time Date: Wed, 12 Oct 2022 20:23:12 -0400 Message-Id: <20221013002334.1894749-13-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221013002334.1894749-1-sashal@kernel.org> References: <20221013002334.1894749-1-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: linux-kernel@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 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) -- 2.35.1