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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 6A00FC43331 for ; Thu, 2 Apr 2020 04:05:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2C3B620776 for ; Thu, 2 Apr 2020 04:05:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="WxmIWpA0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2C3B620776 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 CCE068E0025; Thu, 2 Apr 2020 00:05:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C7E558E000D; Thu, 2 Apr 2020 00:05:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B93F68E0025; Thu, 2 Apr 2020 00:05:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0248.hostedemail.com [216.40.44.248]) by kanga.kvack.org (Postfix) with ESMTP id 9DFE78E000D for ; Thu, 2 Apr 2020 00:05:09 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 559708248068 for ; Thu, 2 Apr 2020 04:05:09 +0000 (UTC) X-FDA: 76661574738.10.boy85_2cf3cb6372e26 X-HE-Tag: boy85_2cf3cb6372e26 X-Filterd-Recvd-Size: 5820 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf35.hostedemail.com (Postfix) with ESMTP for ; Thu, 2 Apr 2020 04:05:08 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B19E820747; Thu, 2 Apr 2020 04:05:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585800308; bh=56foJD0iA+dzxCky6RmLveNhvVuA8xUYKYvVMjgZKos=; h=Date:From:To:Subject:In-Reply-To:From; b=WxmIWpA0eO8RQvTvTzt2tlZDyVxBnmLLi50IlRU6k5im6iQpRyV2RtU7BLfkMIVP0 +D0UILmsZFD1V+rvAfgvsgjuffJZFGbqxX+/S0x4h00zQxJFR5r6v9ec2BgxaiGAfC EhhwXFN0asffIUQvINCtGUyMt9E6Z3I0tUUgmhxc= Date: Wed, 01 Apr 2020 21:05:07 -0700 From: Andrew Morton To: akpm@linux-foundation.org, aneesh.kumar@linux.vnet.ibm.com, hch@lst.de, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, pankaj.gupta.linux@gmail.com, torvalds@linux-foundation.org, willy@infradead.org Subject: [patch 037/155] mm/filemap.c: rewrite pagecache_get_page documentation Message-ID: <20200402040507.73UbTuq4u%akpm@linux-foundation.org> In-Reply-To: <20200401210155.09e3b9742e1c6e732f5a7250@linux-foundation.org> User-Agent: s-nail v14.8.16 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: From: "Matthew Wilcox (Oracle)" Subject: mm/filemap.c: rewrite pagecache_get_page documentation - These were never called PCG flags; they've been called FGP flags since their introduction in 2014. - The FGP_FOR_MMAP flag was misleadingly documented as if it was an alternative to FGP_CREAT instead of an option to it. - Rename the 'offset' parameter to 'index'. - Capitalisation, formatting, rewording. Link: http://lkml.kernel.org/r/20200318140253.6141-9-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Acked-by: Kirill A. Shutemov Reviewed-by: Christoph Hellwig Cc: Aneesh Kumar K.V Cc: Pankaj Gupta Signed-off-by: Andrew Morton --- mm/filemap.c | 55 +++++++++++++++++++++++-------------------------- 1 file changed, 26 insertions(+), 29 deletions(-) --- a/mm/filemap.c~mm-rewrite-pagecache_get_page-documentation +++ a/mm/filemap.c @@ -1574,42 +1574,39 @@ repeat: EXPORT_SYMBOL(find_lock_entry); /** - * pagecache_get_page - find and get a page reference - * @mapping: the address_space to search - * @offset: the page index - * @fgp_flags: PCG flags - * @gfp_mask: gfp mask to use for the page cache data page allocation - * - * Looks up the page cache slot at @mapping & @offset. - * - * PCG flags modify how the page is returned. - * - * @fgp_flags can be: - * - * - FGP_ACCESSED: the page will be marked accessed - * - FGP_LOCK: Page is return locked - * - FGP_CREAT: If page is not present then a new page is allocated using - * @gfp_mask and added to the page cache and the VM's LRU - * list. The page is returned locked and with an increased - * refcount. - * - FGP_FOR_MMAP: Similar to FGP_CREAT, only we want to allow the caller to do - * its own locking dance if the page is already in cache, or unlock the page - * before returning if we had to add the page to pagecache. + * pagecache_get_page - Find and get a reference to a page. + * @mapping: The address_space to search. + * @index: The page index. + * @fgp_flags: %FGP flags modify how the page is returned. + * @gfp_mask: Memory allocation flags to use if %FGP_CREAT is specified. + * + * Looks up the page cache entry at @mapping & @index. + * + * @fgp_flags can be zero or more of these flags: + * + * * %FGP_ACCESSED - The page will be marked accessed. + * * %FGP_LOCK - The page is returned locked. + * * %FGP_CREAT - If no page is present then a new page is allocated using + * @gfp_mask and added to the page cache and the VM's LRU list. + * The page is returned locked and with an increased refcount. + * * %FGP_FOR_MMAP - The caller wants to do its own locking dance if the + * page is already in cache. If the page was allocated, unlock it before + * returning so the caller can do the same dance. * - * If FGP_LOCK or FGP_CREAT are specified then the function may sleep even - * if the GFP flags specified for FGP_CREAT are atomic. + * If %FGP_LOCK or %FGP_CREAT are specified then the function may sleep even + * if the %GFP flags specified for %FGP_CREAT are atomic. * * If there is a page cache page, it is returned with an increased refcount. * - * Return: the found page or %NULL otherwise. + * Return: The found page or %NULL otherwise. */ -struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset, - int fgp_flags, gfp_t gfp_mask) +struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index, + int fgp_flags, gfp_t gfp_mask) { struct page *page; repeat: - page = find_get_entry(mapping, offset); + page = find_get_entry(mapping, index); if (xa_is_value(page)) page = NULL; if (!page) @@ -1631,7 +1628,7 @@ repeat: put_page(page); goto repeat; } - VM_BUG_ON_PAGE(page->index != offset, page); + VM_BUG_ON_PAGE(page->index != index, page); } if (fgp_flags & FGP_ACCESSED) @@ -1656,7 +1653,7 @@ no_page: if (fgp_flags & FGP_ACCESSED) __SetPageReferenced(page); - err = add_to_page_cache_lru(page, mapping, offset, gfp_mask); + err = add_to_page_cache_lru(page, mapping, index, gfp_mask); if (unlikely(err)) { put_page(page); page = NULL; _