From patchwork Tue Dec 8 19:18:41 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ross Zwisler X-Patchwork-Id: 7801701 Return-Path: X-Original-To: patchwork-linux-nvdimm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id B3ADA9F387 for ; Tue, 8 Dec 2015 19:19:01 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id BCC36203FB for ; Tue, 8 Dec 2015 19:19:00 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CDDD02047C for ; Tue, 8 Dec 2015 19:18:59 +0000 (UTC) Received: from ml01.vlan14.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id C36681A1F86; Tue, 8 Dec 2015 11:18:59 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by ml01.01.org (Postfix) with ESMTP id 2EC821A20B8 for ; Tue, 8 Dec 2015 11:18:58 -0800 (PST) Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga103.jf.intel.com with ESMTP; 08 Dec 2015 11:18:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,400,1444719600"; d="scan'208";a="9746618" Received: from rzwisler-desk.amr.corp.intel.com (HELO phyrexia.intel.com) ([10.252.198.110]) by fmsmga004.fm.intel.com with ESMTP; 08 Dec 2015 11:18:56 -0800 From: Ross Zwisler To: linux-kernel@vger.kernel.org Subject: [PATCH v3 3/7] mm: add find_get_entries_tag() Date: Tue, 8 Dec 2015 12:18:41 -0700 Message-Id: <1449602325-20572-4-git-send-email-ross.zwisler@linux.intel.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1449602325-20572-1-git-send-email-ross.zwisler@linux.intel.com> References: <1449602325-20572-1-git-send-email-ross.zwisler@linux.intel.com> Cc: Dave Hansen , Dave Chinner , "J. Bruce Fields" , linux-mm@kvack.org, Andreas Dilger , "H. Peter Anvin" , Jeff Layton , linux-nvdimm@lists.01.org, x86@kernel.org, Ingo Molnar , Ross Zwisler , linux-ext4@vger.kernel.org, xfs@oss.sgi.com, Alexander Viro , Thomas Gleixner , Theodore Ts'o , Jan Kara , linux-fsdevel@vger.kernel.org, Andrew Morton , Matthew Wilcox X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_LOW, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add find_get_entries_tag() to the family of functions that include find_get_entries(), find_get_pages() and find_get_pages_tag(). This is needed for DAX dirty page handling because we need a list of both page offsets and radix tree entries ('indices' and 'entries' in this function) that are marked with the PAGECACHE_TAG_TOWRITE tag. Signed-off-by: Ross Zwisler Reviewed-by: Jan Kara --- include/linux/pagemap.h | 3 +++ mm/filemap.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 71 insertions(+) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 26eabf5..4db0425 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -361,6 +361,9 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start, unsigned int nr_pages, struct page **pages); unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, int tag, unsigned int nr_pages, struct page **pages); +unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start, + int tag, unsigned int nr_entries, + struct page **entries, pgoff_t *indices); struct page *grab_cache_page_write_begin(struct address_space *mapping, pgoff_t index, unsigned flags); diff --git a/mm/filemap.c b/mm/filemap.c index 167a4d9..99dfbc9 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1498,6 +1498,74 @@ repeat: } EXPORT_SYMBOL(find_get_pages_tag); +/** + * find_get_entries_tag - find and return entries that match @tag + * @mapping: the address_space to search + * @start: the starting page cache index + * @tag: the tag index + * @nr_entries: the maximum number of entries + * @entries: where the resulting entries are placed + * @indices: the cache indices corresponding to the entries in @entries + * + * Like find_get_entries, except we only return entries which are tagged with + * @tag. + */ +unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start, + int tag, unsigned int nr_entries, + struct page **entries, pgoff_t *indices) +{ + void **slot; + unsigned int ret = 0; + struct radix_tree_iter iter; + + if (!nr_entries) + return 0; + + rcu_read_lock(); +restart: + radix_tree_for_each_tagged(slot, &mapping->page_tree, + &iter, start, tag) { + struct page *page; +repeat: + page = radix_tree_deref_slot(slot); + if (unlikely(!page)) + continue; + if (radix_tree_exception(page)) { + if (radix_tree_deref_retry(page)) { + /* + * Transient condition which can only trigger + * when entry at index 0 moves out of or back + * to root: none yet gotten, safe to restart. + */ + goto restart; + } + + /* + * A shadow entry of a recently evicted page, a swap + * entry from shmem/tmpfs or a DAX entry. Return it + * without attempting to raise page count. + */ + goto export; + } + if (!page_cache_get_speculative(page)) + goto repeat; + + /* Has the page moved? */ + if (unlikely(page != *slot)) { + page_cache_release(page); + goto repeat; + } +export: + indices[ret] = iter.index; + entries[ret] = page; + if (++ret == nr_entries) + break; + } + rcu_read_unlock(); + return ret; +} +EXPORT_SYMBOL(find_get_entries_tag); + /* * CD/DVDs are error prone. When a medium error occurs, the driver may fail * a _large_ part of the i/o request. Imagine the worst scenario: