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=-8.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 DBA7CC388F7 for ; Tue, 3 Nov 2020 07:49:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 64C432222B for ; Tue, 3 Nov 2020 07:49:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 64C432222B 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 BE8106B0071; Tue, 3 Nov 2020 02:49:48 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B99256B0072; Tue, 3 Nov 2020 02:49:48 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A0EBE6B0073; Tue, 3 Nov 2020 02:49:48 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0088.hostedemail.com [216.40.44.88]) by kanga.kvack.org (Postfix) with ESMTP id 637426B0071 for ; Tue, 3 Nov 2020 02:49:48 -0500 (EST) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0DE2C180AD807 for ; Tue, 3 Nov 2020 07:49:48 +0000 (UTC) X-FDA: 77442332856.14.gold19_1e0673f272b6 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin14.hostedemail.com (Postfix) with ESMTP id E50C718229835 for ; Tue, 3 Nov 2020 07:49:47 +0000 (UTC) X-HE-Tag: gold19_1e0673f272b6 X-Filterd-Recvd-Size: 2934 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Tue, 3 Nov 2020 07:49:47 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id AEF6B67373; Tue, 3 Nov 2020 08:49:44 +0100 (CET) Date: Tue, 3 Nov 2020 08:49:44 +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 11/17] mm/filemap: Add filemap_range_uptodate Message-ID: <20201103074944.GK8389@lst.de> References: <20201102184312.25926-1-willy@infradead.org> <20201102184312.25926-12-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201102184312.25926-12-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: On Mon, Nov 02, 2020 at 06:43:06PM +0000, Matthew Wilcox (Oracle) wrote: > Move the complicated condition and the calculations out of > filemap_update_page() into its own function. The logic looks good, but the flow inside of filemap_update_page looks odd. The patch below relative to this commit shows how I'd do it: diff --git a/mm/filemap.c b/mm/filemap.c index 81b569d818a3f8..304180c022d38a 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2266,40 +2266,39 @@ static int filemap_update_page(struct kiocb *iocb, if (!trylock_page(page)) { if (iocb->ki_flags & (IOCB_NOWAIT | IOCB_NOIO)) goto error; - if (iocb->ki_flags & IOCB_WAITQ) { - if (!first) - goto error; - error = __lock_page_async(page, iocb->ki_waitq); - if (error) - goto error; - } else { + if (!(iocb->ki_flags & IOCB_WAITQ)) { put_and_wait_on_page_locked(page, TASK_KILLABLE); return AOP_TRUNCATED_PAGE; } + if (!first) + goto error; + error = __lock_page_async(page, iocb->ki_waitq); + if (error) + goto error; } + error = AOP_TRUNCATED_PAGE; if (!page->mapping) - goto truncated; - if (filemap_range_uptodate(iocb, mapping, iter, page)) { - unlock_page(page); - return 0; - } + goto error_unlock_page; - if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) { - unlock_page(page); + if (!filemap_range_uptodate(iocb, mapping, iter, page)) { error = -EAGAIN; - } else { + if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) + goto error_unlock_page; error = filemap_read_page(iocb->ki_filp, mapping, page); - if (!error) - return 0; + if (error) + goto error; + return 0; /* filemap_read_page unlocks the page */ } + + unlock_page(page); + return 0; + +error_unlock_page: + unlock_page(page); error: put_page(page); return error; -truncated: - unlock_page(page); - put_page(page); - return AOP_TRUNCATED_PAGE; } static struct page *filemap_create_page(struct file *file,