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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5016BCA9EC5 for ; Wed, 30 Oct 2019 16:33:28 +0000 (UTC) Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 17FE2218AC; Wed, 30 Oct 2019 16:33:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sourceforge.net header.i=@sourceforge.net header.b="l3zU+LYP"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sf.net header.i=@sf.net header.b="LkY/EzF0"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="iGba95ge" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 17FE2218AC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-f2fs-devel-bounces@lists.sourceforge.net Received: from [127.0.0.1] (helo=sfs-ml-2.v29.lw.sourceforge.com) by sfs-ml-2.v29.lw.sourceforge.com with esmtp (Exim 4.90_1) (envelope-from ) id 1iPquV-0006Eq-Il; Wed, 30 Oct 2019 16:33:27 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-2.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1iPquU-0006Eh-6X for linux-f2fs-devel@lists.sourceforge.net; Wed, 30 Oct 2019 16:33:26 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; 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:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=sOObYlWZ41xTgAHiCQDNKqzntjN7TJ231wc+n79zdBk=; b=l3zU+LYPEZEAzu69c6rMPxCMGd kCA+bvhfUBH/P1mga12ZB1fHCzjngzDLBHoaUaC3frN6MX+APcPgMEulsHkfRrH3E/MewlsknWnrq C0RHrsACe8OsWLBgbJzwcq2bvk4yJnFdldI4rFd0W07aKA4VJUs//XLuAb8IeP49bfmU=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; 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:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=sOObYlWZ41xTgAHiCQDNKqzntjN7TJ231wc+n79zdBk=; b=LkY/EzF0iHGzDo9z15sjCyPAUY XA4I0jGoxJxZ1/6VGSejCLXTuaLbj5e9j/LVRqowG2cbNzFTqxW7lEiHlr7lUz8GRbQzowP/Wxs+0 Q/YvWNxio+AcLg9dfKrK2AqtGEuTRAlCkAwontfhpHjscJKA6drW7GMEnXTrDs3HzQOI=; Received: from mail.kernel.org ([198.145.29.99]) by sfi-mx-1.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.2) id 1iPquO-0090HA-2y for linux-f2fs-devel@lists.sourceforge.net; Wed, 30 Oct 2019 16:33:26 +0000 Received: from localhost (unknown [104.132.0.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6BA1D208E3; Wed, 30 Oct 2019 16:33:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572453194; bh=R+x/BiJjAABhO4MBomPKbzt94Ok4oo5wUPTX569SJ6g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=iGba95geeKSbcCK9GWjQH/AJCr6qa7QkMYrle1YEL/ZwFd5UUcgg+TCYjJYgTBXF6 PgpoepMXz5caV3srmydmo6B7IvFHf9OuWgvDXgt/sAtNqr7U2TcGYQl8sXUGhz60MW MhURFz/qimcPaK+szHYt2Tw0wv62Fvj1P0B5gmsg= Date: Wed, 30 Oct 2019 09:33:13 -0700 From: Jaegeuk Kim To: "Theodore Y. Ts'o" Message-ID: <20191030163313.GB34056@jaegeuk-macbookpro.roam.corp.google.com> References: <20191030035518.65477-1-gaoxiang25@huawei.com> <20aa40bd-280d-d223-9f73-d9ed7dbe4f29@huawei.com> <20191030091542.GA24976@architecture4> <19a417e6-8f0e-564e-bc36-59bfc883ec16@huawei.com> <20191030104345.GB170703@architecture4> <20191030151444.GC16197@mit.edu> <20191030155020.GA3953@hsiangkao-HP-ZHAN-66-Pro-G1> <20191030162243.GA18729@mit.edu> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191030162243.GA18729@mit.edu> User-Agent: Mutt/1.8.2 (2017-04-18) X-Headers-End: 1iPquO-0090HA-2y Subject: Re: [f2fs-dev] [PATCH] f2fs: bio_alloc should never fail X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jonathan Corbet , linux-doc@vger.kernel.org, Gao Xiang , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On 10/30, Theodore Y. Ts'o wrote: > On Wed, Oct 30, 2019 at 11:50:37PM +0800, Gao Xiang wrote: > > > > So I'm curious about the original issue in commit 740432f83560 > > ("f2fs: handle failed bio allocation"). Since f2fs manages multiple write > > bios with its internal fio but it seems the commit is not helpful to > > resolve potential mempool deadlock (I'm confused since no calltrace, > > maybe I'm wrong)... > > Two possibilities come to mind. (a) It may be that on older kernels > (when f2fs is backported to older Board Support Package kernels from > the SOC vendors) didn't have the bio_alloc() guarantee, so it was > necessary on older kernels, but not on upstream, or (b) it wasn't > *actually* possible for bio_alloc() to fail and someone added the > error handling in 740432f83560 out of paranoia. Yup, I was checking old device kernels but just stopped digging it out. Instead, I hesitate to apply this patch since I can't get why we need to get rid of this code for clean-up purpose. This may be able to bring some hassles when backporting to android/device kernels. > > (Hence my suggestion that in the ext4 version of the patch, we add a > code comment justifying why there was no error checking, to make it > clear that this was a deliberate choice. :-) > > - Ted _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel