From patchwork Sat Mar 20 05:40:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12152273 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 06052C433EB for ; Sat, 20 Mar 2021 05:43:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E395561999 for ; Sat, 20 Mar 2021 05:43:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230060AbhCTFnG (ORCPT ); Sat, 20 Mar 2021 01:43:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230010AbhCTFmk (ORCPT ); Sat, 20 Mar 2021 01:42:40 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D601C061762; Fri, 19 Mar 2021 22:42:40 -0700 (PDT) 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=+y/5FoFjLrWI2aA5leeXHbMd9T+liO6cqHRjVQ4zX7g=; b=tHN7vv86r++fKO7VbcELKmOtYj ytR/rlYj8k7h/P9xrcgHzXnWPUDm5Ur3vjgSlvyZDOIr2QqLcAcphcplksUqNLr+tejLqmVTWUHHn OB9xjs9rBnoxFW8V54cvyqv4gsTuHN8nzcdEr23gIdzMr7w7WQsB+R+S0kN5v7qiwI93Y2NONe3Qh KuqS/z0C/osOFqLoKYgruZra5PVGK0PwBSJH47wIxx22rGRHJj12r5Kjh/RUKYbtPZimtbzrQKRa+ Zd+ZyfdkekkpHbQctm466QxQK7znWnYCkV4MwGjUNPZ3dLj4/Sx8hEfH+IitTe+lMv1z6xvFI7ZeN JtNleeyA==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lNUNW-005SYb-Sg; Sat, 20 Mar 2021 05:42:30 +0000 From: "Matthew Wilcox (Oracle)" To: linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-cachefs@redhat.com, linux-afs@lists.infradead.org Subject: [PATCH v5 12/27] mm: Add folio_index, folio_file_page and folio_contains Date: Sat, 20 Mar 2021 05:40:49 +0000 Message-Id: <20210320054104.1300774-13-willy@infradead.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210320054104.1300774-1-willy@infradead.org> References: <20210320054104.1300774-1-willy@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org folio_index() is the equivalent of page_index() for folios. folio_file_page() is the equivalent of find_subpage(). folio_contains() is the equivalent of thp_contains(). Signed-off-by: Matthew Wilcox (Oracle) --- include/linux/pagemap.h | 53 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 6676210addf6..f29c96ed3721 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -462,6 +462,59 @@ static inline bool thp_contains(struct page *head, pgoff_t index) return page_index(head) == (index & ~(thp_nr_pages(head) - 1UL)); } +#define swapcache_index(folio) __page_file_index(&(folio)->page) + +/** + * folio_index - File index of a folio. + * @folio: The folio. + * + * For a folio which is either in the page cache or the swap cache, + * return its index within the address_space it belongs to. If you know + * the page is definitely in the page cache, you can look at the folio's + * index directly. + * + * Return: The index (offset in units of pages) of a folio in its file. + */ +static inline pgoff_t folio_index(struct folio *folio) +{ + if (unlikely(FolioSwapCache(folio))) + return swapcache_index(folio); + return folio->page.index; +} + +/** + * folio_file_page - The page for a particular index. + * @folio: The folio which contains this index. + * @index: The index we want to look up. + * + * Sometimes after looking up a folio in the page cache, we need to + * obtain the specific page for an index (eg a page fault). + * + * Return: The page containing the file data for this index. + */ +static inline struct page *folio_file_page(struct folio *folio, pgoff_t index) +{ + return &folio->page + (index & (folio_nr_pages(folio) - 1)); +} + +/** + * folio_contains - Does this folio contain this index? + * @folio: The folio. + * @index: The page index within the file. + * + * Context: The caller should have the page locked in order to prevent + * (eg) shmem from moving the page between the page cache and swap cache + * and changing its index in the middle of the operation. + * Return: true or false. + */ +static inline bool folio_contains(struct folio *folio, pgoff_t index) +{ + /* HugeTLBfs indexes the page cache in units of hpage_size */ + if (PageHuge(&folio->page)) + return folio->page.index == index; + return index - folio_index(folio) < folio_nr_pages(folio); +} + /* * Given the page we found in the page cache, return the page corresponding * to this index in the file