From nobody Fri Dec 19 06:29:31 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 8CE78ECAAA1 for ; Mon, 24 Oct 2022 16:53:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233313AbiJXQxC (ORCPT ); Mon, 24 Oct 2022 12:53:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35108 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235300AbiJXQtW (ORCPT ); Mon, 24 Oct 2022 12:49:22 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D2E28BB84; Mon, 24 Oct 2022 08:32:34 -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 C91F4B81995; Mon, 24 Oct 2022 12:54:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21E11C433C1; Mon, 24 Oct 2022 12:54:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666616067; bh=tyY7mApUCKy3nxZR8IiT8fEapo3BTVDOMAVT+cOVgtA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z1ASDSmYEWfn1K2geTOOIfdAC3VWtboNufZNGEAzxAvkNeqxJjHRUHmNZMfNvk1zh bGNHhSuY+3euyI4yFJErEa3ZpbCQ5F55eoUjxXi+PI9UTZkhHLd/yHJ/t+KBYtlaf9 XiK2jt5NiIWSjzLpZwk8J1YbPp1841uP1nrvdpjQ= 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 5.15 488/530] blk-throttle: prevent overflow while calculating wait time Date: Mon, 24 Oct 2022 13:33:52 +0200 Message-Id: <20221024113107.138651678@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113044.976326639@linuxfoundation.org> References: <20221024113044.976326639@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 7c4e7993ba97..68cf8dbb4c67 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -950,7 +950,7 @@ 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 @@ -967,10 +967,8 @@ 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