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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS 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 46A1FC433DB for ; Wed, 3 Mar 2021 06:07:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AA95E64E51 for ; Wed, 3 Mar 2021 06:07:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AA95E64E51 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DD3088D012B; Wed, 3 Mar 2021 01:07:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DAA8C8D0127; Wed, 3 Mar 2021 01:07:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C99B38D012B; Wed, 3 Mar 2021 01:07:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0073.hostedemail.com [216.40.44.73]) by kanga.kvack.org (Postfix) with ESMTP id B07208D0127 for ; Wed, 3 Mar 2021 01:07:40 -0500 (EST) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 736F0181BD79A for ; Wed, 3 Mar 2021 06:07:40 +0000 (UTC) X-FDA: 77877531480.14.0BCD478 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf13.hostedemail.com (Postfix) with ESMTP id 27741E0011ED for ; Wed, 3 Mar 2021 06:07:39 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 8E01064EBD; Wed, 3 Mar 2021 06:07:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614751658; bh=03wcpTwHahDBsiSbVcpeFCVxgD9QL3kxEznzoucjZUU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Jx/JVO4MnKxyigL9ai/tLjmttmUs2C41FzRTRFKaORumw57eY6QuomDS7H6DTsHBD 2BYjnPJKl3oZB3SzW1wHAnyx+X6lf+DLB/lQHMQege7J6fSSRiyZY+Q7ymMShA93CV 36DLphGpISvamlNUHRfRnxclRvObLisuVRy2ULCE= Date: Tue, 2 Mar 2021 22:07:35 -0800 From: Andrew Morton To: Matthew Wilcox Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Kent Overstreet , Christoph Hellwig Subject: Re: [PATCH] mm/filemap: Use filemap_read_page in filemap_fault Message-Id: <20210302220735.1f150f28323f676d2955ab49@linux-foundation.org> In-Reply-To: <20210303013313.GZ2723601@casper.infradead.org> References: <20210226140011.2883498-1-willy@infradead.org> <20210302173039.4625f403846abd20413f6dad@linux-foundation.org> <20210303013313.GZ2723601@casper.infradead.org> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: bxc8cdiophpm1m9pmizuqtufr9noa8ab X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 27741E0011ED Received-SPF: none (linux-foundation.org>: No applicable sender policy available) receiver=imf13; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614751659-436628 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, 3 Mar 2021 01:33:13 +0000 Matthew Wilcox wrote: > On Tue, Mar 02, 2021 at 05:30:39PM -0800, Andrew Morton wrote: > > On Fri, 26 Feb 2021 14:00:11 +0000 "Matthew Wilcox (Oracle)" wrote: > > > > > After splitting generic_file_buffered_read() into smaller parts, it > > > turns out we can reuse one of the parts in filemap_fault(). This fixes > > > an oversight -- waiting for the I/O to complete is now interruptible > > > by a fatal signal. And it saves us a few bytes of text in an unlikely > > > path. > > > > We also handle AOP_TRUNCATED_PAGE which the present code fails to do. > > Should this be in the changelog? > > No, the present code does handle AOP_TRUNCATED_PAGE. It's perhaps not > the clearest in the diff, but it's there. Here's git show -U5: > > - ClearPageError(page); > fpin = maybe_unlock_mmap_for_io(vmf, fpin); > - error = mapping->a_ops->readpage(file, page); > - if (!error) { > - wait_on_page_locked(page); > - if (!PageUptodate(page)) > - error = -EIO; > - } > + error = filemap_read_page(file, mapping, page); > if (fpin) > goto out_retry; > put_page(page); > > if (!error || error == AOP_TRUNCATED_PAGE) > goto retry_find; > > - shrink_readahead_size_eio(ra); > return VM_FAULT_SIGBUS; But ->readpage() doesn't check for !mapping (does it?). So the ->readpage() cannot return AOP_TRUNCATED_PAGE. However filemap_read_page() does check for !mapping. So current -linus doesn't check for !mapping, and post-willy does do this?