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 7C6F1C433EF for ; Tue, 30 Nov 2021 06:43:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238750AbhK3Gqf (ORCPT ); Tue, 30 Nov 2021 01:46:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233099AbhK3Gqf (ORCPT ); Tue, 30 Nov 2021 01:46:35 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BDC28C061574; Mon, 29 Nov 2021 22:43:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=LbNjrOn/TR2DrlvunPAnXmZeUtVG1jTEm/amQL+7ym4=; b=uwQm3elvRY63sSd28fQaOo6GSO qwcqB7PI3Ee+ZNwfoKvARal12tj6fXqox/uqPWdZWzgjas0nWpkw2DPFGmLwha8f6qLIZbmiU5ykM SFCaAlohCL+RqZoejpKVHS64SiqmklbW5mzgofKxuzyCAoFPOOGi/OP6zJyvfCy8BaZ2kqRbnhFeP zc7DjA4qJa1Y1GmVqwL825mt9Tpok0yOWV1yqzj5ij4/yWqj0xlAtC6rqJqrJQBQBohzjZctdytMr iU2HwGIBPSGgPyisnozso/6UaFFR0sigr/lE9CFLBbBqFR3zHbYVv20DJCryAVAQO3YvclMdml6kr 19EJViHA==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mrwrB-003pTb-6C; Tue, 30 Nov 2021 06:43:13 +0000 Date: Mon, 29 Nov 2021 22:43:13 -0800 From: Christoph Hellwig To: Yu Kuai Cc: hch@infradead.org, tj@kernel.org, axboe@kernel.dk, cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com Subject: Re: [PATCH v2 1/2] blk-throtl: move WARN_ON_ONCE() from throtl_rb_first() to it's caller Message-ID: References: <20211130011730.2584339-1-yukuai3@huawei.com> <20211130011730.2584339-2-yukuai3@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211130011730.2584339-2-yukuai3@huawei.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 30, 2021 at 09:17:29AM +0800, Yu Kuai wrote: > Prepare to reintroduce tg_drain_bios(), which will iterate until > throtl_rb_first() return NULL. > > Signed-off-by: Yu Kuai > --- > block/blk-throttle.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/block/blk-throttle.c b/block/blk-throttle.c > index 39bb6e68a9a2..f7244190cb2f 100644 > --- a/block/blk-throttle.c > +++ b/block/blk-throttle.c > @@ -502,7 +502,6 @@ throtl_rb_first(struct throtl_service_queue *parent_sq) > struct rb_node *n; > > n = rb_first_cached(&parent_sq->pending_tree); > - WARN_ON_ONCE(!n); > if (!n) > return NULL; > return rb_entry_tg(n); > @@ -521,8 +520,10 @@ static void update_min_dispatch_time(struct throtl_service_queue *parent_sq) > struct throtl_grp *tg; > > tg = throtl_rb_first(parent_sq); > - if (!tg) > + if (!tg) { > + WARN_ON_ONCE(1); > return; if (WARN_ON_ONCE(!tg)) return; > tg = throtl_rb_first(parent_sq); > - if (!tg) > + if (!tg) { > + WARN_ON_ONCE(1); > break; > + } Same here.