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 46161C433F5 for ; Mon, 10 Jan 2022 18:11:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238765AbiAJSL3 (ORCPT ); Mon, 10 Jan 2022 13:11:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238764AbiAJSL3 (ORCPT ); Mon, 10 Jan 2022 13:11:29 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EEEB0C06173F; Mon, 10 Jan 2022 10:11:28 -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=IXDclvvGfX8g/ZBckJ/3SLWrdaDRKpz0LF1OPGXVzvI=; b=ff+m+P71beGj0MkK/YASQ9YUEQ 6eQGd4BXDI642TW373K/AecrqG2BPxwVOprIKkkjlP70PP7awfl7CTMA6I7YbEop3wWuddvBz0Tlr w66cIGirclHcNqmgQiHr2CJvcJx+SKYjTSzTJjwCZFrlT0dJPsdFXvZ9CibBXuWnHcSlW+0TPBklH LFEAfaW63NFoBQEG9MhZCdDRHOi52p6SWuc4V79Fy+VAP1UfgAy6nQbSvuJVRFsrGrZz0NLtU07dJ h4lyedzaF5yBW8OA/yAvUSf/ms70Mk2agPsxwzmwOZgd1CBnmOCHG1ooJOBe3AgSZfP21flP9asVi 3FtJ2plg==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1n6z8Y-00Cgu5-33; Mon, 10 Jan 2022 18:11:18 +0000 Date: Mon, 10 Jan 2022 10:11:18 -0800 From: "hch@infradead.org" To: Brian Foster Cc: Dave Chinner , "Darrick J. Wong" , "hch@infradead.org" , Matthew Wilcox , Trond Myklebust , "linux-fsdevel@vger.kernel.org" , "trondmy@kernel.org" , "axboe@kernel.dk" , "linux-xfs@vger.kernel.org" Subject: Re: [PATCH] iomap: Address soft lockup in iomap_finish_ioend() Message-ID: References: <20220104192227.GA398655@magnolia> <20220104215227.GJ945095@dread.disaster.area> <20220104231230.GG31606@magnolia> <20220105021022.GL945095@dread.disaster.area> <20220105220421.GM945095@dread.disaster.area> <20220110081847.GW945095@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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-xfs@vger.kernel.org On Mon, Jan 10, 2022 at 12:45:01PM -0500, Brian Foster wrote: > With regard to the iterators, my understanding was that > bio_for_each_segment_all() walks the multipage bvecs but > bio_for_each_segment() does not, but that could certainly be wrong as I > find the iterators a bit confusing. Either way, the most recent test > with the ioend granular filter implies that a single ioend can still > become a soft lockup vector from non-atomic context. the segment iterators iterate over the pages segments, the bvec iterators over the multi-page bvecs. The _all suffix means it iterates over the whole bio independent of clones and partial submission state and is for use in the cmpletion handlers. The version without it are for use in the block drivers.