From nobody Fri Oct 17 10:31:31 2025 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 5605AC4332F for ; Wed, 19 Oct 2022 09:42:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234043AbiJSJmo (ORCPT ); Wed, 19 Oct 2022 05:42:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234193AbiJSJjL (ORCPT ); Wed, 19 Oct 2022 05:39:11 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DCC51DED22; Wed, 19 Oct 2022 02:16:05 -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 A8400617D4; Wed, 19 Oct 2022 09:14:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B671FC433D7; Wed, 19 Oct 2022 09:14:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666170843; bh=FExqy90cvvKeQwgBS3G6vEsaIKxkIk3GIJCelzs91+g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ftzSWO+eC6HulXbNI8UJ63pYwCK6i+VcXgU2h9VAyJgIlpg69EXnQps8JKP9WZkZv mk5SRnj9GBHz0wVcKWIUs5KysclTyApt21i7O68V0R3VLWyCG+XTuRr82q6RhLwR36 wcKVQZjZW3oQqYkH1F7bU4g85UG5agWgO5yVr3Ag= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yu Kuai , Tejun Heo , Jens Axboe , Sasha Levin Subject: [PATCH 6.0 807/862] blk-throttle: prevent overflow while calculating wait time Date: Wed, 19 Oct 2022 10:34:54 +0200 Message-Id: <20221019083325.560259314@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221019083249.951566199@linuxfoundation.org> References: <20221019083249.951566199@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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@huaweiclou= d.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 3c02a9b3275a..35cf744ea9d1 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 =3D 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 =3D throtl_bio_data_size(bio); =20 @@ -824,10 +824,8 @@ static bool tg_with_in_bps_limit(struct throtl_grp *tg= , struct bio *bio, jiffy_elapsed_rnd =3D tg->td->throtl_slice; =20 jiffy_elapsed_rnd =3D roundup(jiffy_elapsed_rnd, tg->td->throtl_slice); - - tmp =3D bps_limit * jiffy_elapsed_rnd; - do_div(tmp, HZ); - bytes_allowed =3D tmp; + bytes_allowed =3D mul_u64_u64_div_u64(bps_limit, (u64)jiffy_elapsed_rnd, + (u64)HZ); =20 if (tg->bytes_disp[rw] + bio_size <=3D bytes_allowed) { if (wait) --=20 2.35.1