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=HEADER_FROM_DIFFERENT_DOMAINS, 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 CF474C3F2CD for ; Fri, 28 Feb 2020 20:35:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8978246A8 for ; Fri, 28 Feb 2020 20:35:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725900AbgB1Ufm (ORCPT ); Fri, 28 Feb 2020 15:35:42 -0500 Received: from mx2.suse.de ([195.135.220.15]:54530 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725730AbgB1Ufm (ORCPT ); Fri, 28 Feb 2020 15:35:42 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id CB895AE95; Fri, 28 Feb 2020 20:35:40 +0000 (UTC) Date: Fri, 28 Feb 2020 14:35:38 -0600 From: Goldwyn Rodrigues To: Matthew Wilcox Cc: Christoph Hellwig , Ritesh Harjani , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, darrick.wong@oracle.com Subject: Re: [PATCH v2] iomap: return partial I/O count on error in iomap_dio_bio_actor Message-ID: <20200228203538.s52t64zcurna77cu@fiona> References: <20200220152355.5ticlkptc7kwrifz@fiona> <20200221045110.612705204E@d06av21.portsmouth.uk.ibm.com> <20200225205342.GA12066@infradead.org> <20200228194401.o736qvvr4zpklyiz@fiona> <20200228195954.GJ29971@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200228195954.GJ29971@bombadil.infradead.org> User-Agent: NeoMutt/20180716 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 11:59 28/02, Matthew Wilcox wrote: > On Fri, Feb 28, 2020 at 01:44:01PM -0600, Goldwyn Rodrigues wrote: > > +++ b/fs/iomap/direct-io.c > > @@ -264,7 +264,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, > > size_t n; > > if (dio->error) { > > iov_iter_revert(dio->submit.iter, copied); > > - copied = ret = 0; > > + ret = 0; > > goto out; > > There's another change here ... look at the out label > > out: > /* Undo iter limitation to current extent */ > iov_iter_reexpand(dio->submit.iter, orig_count - copied); > if (copied) > return copied; > return ret; > > so you're also changing by how much the iter is reexpanded. I > don't know if it's the appropriate amount; I still don't quite get the > iov_iter complexities. > Ah, okay. Now I understand what Christoph was saying. I suppose it is safe to remove iov_iter_reexpand(). I don't see any other goto to this label which will have a non-zero copied value. And we have already performed the iov_iter_revert(). -- Goldwyn