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=-12.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 2861DC433E1 for ; Wed, 19 Aug 2020 18:49:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D76120758 for ; Wed, 19 Aug 2020 18:49:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="s/Fj5e9N" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726795AbgHSSt3 (ORCPT ); Wed, 19 Aug 2020 14:49:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34088 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726846AbgHSStH (ORCPT ); Wed, 19 Aug 2020 14:49:07 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C90EEC061344; Wed, 19 Aug 2020 11:49:06 -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=p9w3DQmYzQVsLNeG7R7MdPybBJO6jXoNftILGTf+IE0=; b=s/Fj5e9N4i8MPBUyLdHzmYltJH W95qh4IqdO+bgeV/dKBXO34yVAYFsjEf92o4CweV2SCp098vES4xu2VCaPtffdljiQgVFusO0lPtR mVxJiPVCa8G/0SULJ8xl53dhiTptsPOCo1sLkBvQH4SedICuiVc6SD74X35sX59AOfjyMClCYGUzr 978Ku/CwTM5ej8GuG7J5Hwsz0uakDJFFzqaSPsaVyedNaFZ8G9IsmSt4Xk4MOwfTnNBgqvB1gV7u9 lDbXNqBWefAsnr4EO2lUpq8B6IotkPmE/O6f+kHf5745L3YB4RJNSt3UO0+ggGjOLpewsg3FA6VVz e6DXDilg==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1k8T8p-0006UC-TJ; Wed, 19 Aug 2020 18:48:56 +0000 From: "Matthew Wilcox (Oracle)" To: linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , Andrew Morton , Hugh Dickins , William Kucharski , Jani Nikula , Alexey Dobriyan , Johannes Weiner , Chris Wilson , Matthew Auld , Huang Ying , intel-gfx@lists.freedesktop.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 7/8] mm: Return head page from find_lock_entry Date: Wed, 19 Aug 2020 19:48:49 +0100 Message-Id: <20200819184850.24779-8-willy@infradead.org> X-Mailer: git-send-email 2.21.3 In-Reply-To: <20200819184850.24779-1-willy@infradead.org> References: <20200819184850.24779-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Convert the one caller of find_lock_entry() to cope with a head page being returned instead of the subpage for the index. Signed-off-by: Matthew Wilcox (Oracle) --- include/linux/pagemap.h | 12 ++++++++++++ mm/filemap.c | 25 +++++++++++-------------- mm/shmem.c | 15 ++++++++------- 3 files changed, 31 insertions(+), 21 deletions(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 8261c64f592d..de8f3758ceaa 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -371,6 +371,18 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping, mapping_gfp_mask(mapping)); } +/* + * Is this index for one of the subpages of this page? + * This should always be called for a locked, non-hugetlbfs page. + */ +static inline bool thp_valid_index(struct page *head, pgoff_t index) +{ + VM_BUG_ON_PAGE(PageHuge(head), head); + VM_BUG_ON_PAGE(!PageLocked(head), head); + + return head->index == (index & ~(thp_nr_pages(head) - 1)); +} + /* * Given the page we found in the page cache, return the page corresponding * to this index in the file diff --git a/mm/filemap.c b/mm/filemap.c index 5a87e1bdddd6..6594baae7cd2 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1594,37 +1594,34 @@ struct page *find_get_entry(struct address_space *mapping, pgoff_t index) } /** - * find_lock_entry - locate, pin and lock a page cache entry - * @mapping: the address_space to search - * @offset: the page cache index + * find_lock_entry - Locate and lock a page cache entry. + * @mapping: The address_space to search. + * @index: The page cache index. * - * Looks up the page cache slot at @mapping & @offset. If there is a - * page cache page, it is returned locked and with an increased - * refcount. + * Looks up the page at @mapping & @index. If there is a page in the + * cache, the head page is returned locked and with an increased refcount. * * If the slot holds a shadow entry of a previously evicted page, or a * swap entry from shmem/tmpfs, it is returned. * - * find_lock_entry() may sleep. - * - * Return: the found page or shadow entry, %NULL if nothing is found. + * Context: May sleep. + * Return: The head page or shadow entry, %NULL if nothing is found. */ -struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset) +struct page *find_lock_entry(struct address_space *mapping, pgoff_t index) { struct page *page; repeat: - page = find_get_entry(mapping, offset); + page = find_get_entry(mapping, index); if (page && !xa_is_value(page)) { lock_page(page); /* Has the page been truncated? */ - if (unlikely(page_mapping(page) != mapping)) { + if (unlikely(page->mapping != mapping)) { unlock_page(page); put_page(page); goto repeat; } - page = find_subpage(page, offset); - VM_BUG_ON_PAGE(page_to_pgoff(page) != offset, page); + VM_BUG_ON_PAGE(!thp_valid_index(page, index), page); } return page; } diff --git a/mm/shmem.c b/mm/shmem.c index 271548ca20f3..bbb43e9d35df 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1834,8 +1834,9 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, page = NULL; } if (page || sgp == SGP_READ) { - *pagep = page; - return 0; + if (page && PageTransHuge(page)) + hindex = round_down(index, HPAGE_PMD_NR); + goto out; } /* @@ -1961,14 +1962,13 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, * it now, lest undo on failure cancel our earlier guarantee. */ if (sgp != SGP_WRITE && !PageUptodate(page)) { - struct page *head = compound_head(page); int i; - for (i = 0; i < compound_nr(head); i++) { - clear_highpage(head + i); - flush_dcache_page(head + i); + for (i = 0; i < compound_nr(page); i++) { + clear_highpage(page + i); + flush_dcache_page(page + i); } - SetPageUptodate(head); + SetPageUptodate(page); } /* Perhaps the file has been truncated since we checked */ @@ -1984,6 +1984,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, error = -EINVAL; goto unlock; } +out: *pagep = page + index - hindex; return 0; -- 2.28.0