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=-5.2 required=3.0 tests=BAYES_00, 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 D9C66C388F7 for ; Tue, 3 Nov 2020 07:34:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 45F012222B for ; Tue, 3 Nov 2020 07:34:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 45F012222B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B4C986B005C; Tue, 3 Nov 2020 02:34:31 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AD48B6B005D; Tue, 3 Nov 2020 02:34:31 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9C3E16B0068; Tue, 3 Nov 2020 02:34:31 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0228.hostedemail.com [216.40.44.228]) by kanga.kvack.org (Postfix) with ESMTP id 705EA6B005C for ; Tue, 3 Nov 2020 02:34:31 -0500 (EST) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 147EB8249980 for ; Tue, 3 Nov 2020 07:34:31 +0000 (UTC) X-FDA: 77442294342.07.week33_4713b76272b6 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin07.hostedemail.com (Postfix) with ESMTP id ECFA31803F9A7 for ; Tue, 3 Nov 2020 07:34:30 +0000 (UTC) X-HE-Tag: week33_4713b76272b6 X-Filterd-Recvd-Size: 1945 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Tue, 3 Nov 2020 07:34:30 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id BE92367373; Tue, 3 Nov 2020 08:34:27 +0100 (CET) Date: Tue, 3 Nov 2020 08:34:27 +0100 From: Christoph Hellwig To: "Matthew Wilcox (Oracle)" Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, hch@lst.de, kent.overstreet@gmail.com Subject: Re: [PATCH 07/17] mm/filemap: Change filemap_read_page calling conventions Message-ID: <20201103073427.GG8389@lst.de> References: <20201102184312.25926-1-willy@infradead.org> <20201102184312.25926-8-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201102184312.25926-8-willy@infradead.org> User-Agent: Mutt/1.5.17 (2007-11-01) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > +static int filemap_read_page(struct file *file, struct address_space *mapping, > + struct page *page) I still think we should drop the mapping argument as well. > + if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) { > + unlock_page(page); > + put_page(page); > + return ERR_PTR(-EAGAIN); > + } > + error = filemap_read_page(iocb->ki_filp, mapping, page); > + if (!error) > + return page; I think a goto error for the error cases would be much more useful. That would allow to also share the error put_page for the flag check above and the truncated case below, but most importantly make the code flow obvious vs the early return for the success case. > - return filemap_read_page(iocb, filp, mapping, page); > + if (!error) > + error = filemap_read_page(iocb->ki_filp, mapping, page); > + if (!error) > + return page; > + put_page(page); > + if (error == -EEXIST || error == AOP_TRUNCATED_PAGE) > + return NULL; > + return ERR_PTR(error); Same here.