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=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 DB0C5C55178 for ; Fri, 6 Nov 2020 08:14:25 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 525FA206FB for ; Fri, 6 Nov 2020 08:14:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 525FA206FB 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 92E8B6B0070; Fri, 6 Nov 2020 03:14:24 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8B7AB6B0074; Fri, 6 Nov 2020 03:14:24 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7A4686B0075; Fri, 6 Nov 2020 03:14:24 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0081.hostedemail.com [216.40.44.81]) by kanga.kvack.org (Postfix) with ESMTP id 44EA06B0070 for ; Fri, 6 Nov 2020 03:14:24 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id E6BDD8249980 for ; Fri, 6 Nov 2020 08:14:23 +0000 (UTC) X-FDA: 77453281206.28.can38_550d4ae272d1 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin28.hostedemail.com (Postfix) with ESMTP id B76996D6D for ; Fri, 6 Nov 2020 08:14:23 +0000 (UTC) X-HE-Tag: can38_550d4ae272d1 X-Filterd-Recvd-Size: 3163 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf22.hostedemail.com (Postfix) with ESMTP for ; Fri, 6 Nov 2020 08:14:23 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 46A1D68B05; Fri, 6 Nov 2020 09:14:21 +0100 (CET) Date: Fri, 6 Nov 2020 09:14:20 +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 v2 11/18] mm/filemap: Convert filemap_update_page to return an errno Message-ID: <20201106081420.GF31585@lst.de> References: <20201104204219.23810-1-willy@infradead.org> <20201104204219.23810-12-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201104204219.23810-12-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 Wed, Nov 04, 2020 at 08:42:12PM +0000, Matthew Wilcox (Oracle) wrote: > Use AOP_TRUNCATED_PAGE to indicate that no error occurred, but the > page we looked up is no longer valid. > > Signed-off-by: Matthew Wilcox (Oracle) > Reviewed-by: Kent Overstreet > --- > mm/filemap.c | 42 +++++++++++++++++++----------------------- > 1 file changed, 19 insertions(+), 23 deletions(-) > > diff --git a/mm/filemap.c b/mm/filemap.c > index 25945fefdd39..93c054f51677 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -2231,24 +2231,21 @@ static int filemap_read_page(struct file *file, struct address_space *mapping, > return error; > } > > +static int filemap_update_page(struct kiocb *iocb, > + struct address_space *mapping, struct iov_iter *iter, > + struct page *page, loff_t pos, loff_t count) > { > struct inode *inode = mapping->host; > int error; > > if (iocb->ki_flags & IOCB_WAITQ) { > error = lock_page_async(page, iocb->ki_waitq); > + if (error) > + goto error; > } else { > if (!trylock_page(page)) { > put_and_wait_on_page_locked(page, TASK_KILLABLE); > + return AOP_TRUNCATED_PAGE; > } > } > > @@ -2267,25 +2264,24 @@ static struct page *filemap_update_page(struct kiocb *iocb, struct file *filp, > goto readpage; > uptodate: > unlock_page(page); > + return 0; > > readpage: > if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) { > unlock_page(page); > + error = -EAGAIN; > + } else { > + error = filemap_read_page(iocb->ki_filp, mapping, page); > + if (!error) > + return 0; > } > +error: > put_page(page); > + return error; > truncated: > unlock_page(page); > put_page(page); > + return AOP_TRUNCATED_PAGE; We could still consolidate the page unlocking by having another label. Or even better move the put_page into the caller like I did in my series, which would conceputally fit in pretty nicely here: > + err = filemap_update_page(iocb, mapping, iter, page, > pg_pos, pg_count); > + if (err) > pvec->nr--; But otherwise this looks good: Reviewed-by: Christoph Hellwig