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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 69E3FC5517A for ; Tue, 10 Nov 2020 03:37:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1B33920731 for ; Tue, 10 Nov 2020 03:37:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ZhVL+Sf9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731300AbgKJDhT (ORCPT ); Mon, 9 Nov 2020 22:37:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44280 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731366AbgKJDhP (ORCPT ); Mon, 9 Nov 2020 22:37:15 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E5853C0617A6 for ; Mon, 9 Nov 2020 19:37:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=QHs5v1YUXVPwXe5xLPhKJGU4nL7RPpQ66tQpFDSktyk=; b=ZhVL+Sf93+xtmAEFEcO++LSC/1 RDMbcAJb01vlxAK5e5QhAcNa6/lY2++fXF0F6ErXPRs2N/uBi3IGh006Ix3Jyx7fndTTUuAQ8qLKN awFQR0b9UVuh4ICLrBmlh/CZQBXFAXhcNzAA0O1wzdnUu1MdTNq35zcaGu2Jooh9jVPmN+jVe0F9S SU36qaZe6q4loORH8mIueLOuCvY9nnDa1AT5x9huLU2QbyY5ydOQO2fwTUWdLbMyRpaCCFGCekJNV OIuHW8HSi40R/vu4dS7t7+OcnNfe2VyzoeRd5KUD2l43ua9k0CZZKCCW4Rm5QeZdmzx6DVItaNvcP Jb2aXd9w==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kcKT2-000662-Fi; Tue, 10 Nov 2020 03:37:12 +0000 From: "Matthew Wilcox (Oracle)" To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , hch@lst.de, kent.overstreet@gmail.com Subject: [PATCH v3 11/18] mm/filemap: Convert filemap_update_page to return an errno Date: Tue, 10 Nov 2020 03:36:56 +0000 Message-Id: <20201110033703.23261-12-willy@infradead.org> X-Mailer: git-send-email 2.21.3 In-Reply-To: <20201110033703.23261-1-willy@infradead.org> References: <20201110033703.23261-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Use AOP_TRUNCATED_PAGE to indicate that no error occurred, but the page we looked up is no longer valid. In this case, the reference to the page will have been removed; if we hit any other error, the caller will release the reference. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Kent Overstreet --- mm/filemap.c | 38 +++++++++++++++++--------------------- 1 file changed, 17 insertions(+), 21 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index ddc881c9d253..60ce7f15cc7e 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 struct page *filemap_update_page(struct kiocb *iocb, struct file *filp, - struct iov_iter *iter, struct page *page, loff_t pos, - loff_t count) +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 address_space *mapping = filp->f_mapping; struct inode *inode = mapping->host; int error; if (iocb->ki_flags & IOCB_WAITQ) { error = lock_page_async(page, iocb->ki_waitq); - if (error) { - put_page(page); - return ERR_PTR(error); - } + if (error) + return error; } else { if (!trylock_page(page)) { put_and_wait_on_page_locked(page, TASK_KILLABLE); - return NULL; + return AOP_TRUNCATED_PAGE; } } @@ -2267,25 +2264,21 @@ static struct page *filemap_update_page(struct kiocb *iocb, struct file *filp, goto readpage; uptodate: unlock_page(page); - return page; + return 0; readpage: if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) { unlock_page(page); - put_page(page); - return ERR_PTR(-EAGAIN); + return -EAGAIN; } error = filemap_read_page(iocb->ki_filp, mapping, page); - if (!error) - return page; - put_page(page); if (error == AOP_TRUNCATED_PAGE) - return NULL; - return ERR_PTR(error); + put_page(page); + return error; truncated: unlock_page(page); put_page(page); - return NULL; + return AOP_TRUNCATED_PAGE; } static int filemap_create_page(struct file *file, @@ -2379,11 +2372,12 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, goto err; } - page = filemap_update_page(iocb, filp, iter, page, + err = filemap_update_page(iocb, mapping, iter, page, pg_pos, pg_count); - if (IS_ERR_OR_NULL(page)) { + if (err) { + if (err < 0) + put_page(page); pvec->nr--; - err = PTR_ERR_OR_ZERO(page); } } } @@ -2391,6 +2385,8 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, err: if (likely(pvec->nr)) return 0; + if (err == AOP_TRUNCATED_PAGE) + goto find_page; if (err) return err; /* -- 2.28.0