From patchwork Tue Apr 19 04:50:42 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shiyang Ruan X-Patchwork-Id: 12817340 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E596EC433FE for ; Tue, 19 Apr 2022 04:51:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 981D48D003B; Tue, 19 Apr 2022 00:50:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8DEC98D0032; Tue, 19 Apr 2022 00:50:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 70ABC8D003B; Tue, 19 Apr 2022 00:50:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.a.hostedemail.com [64.99.140.24]) by kanga.kvack.org (Postfix) with ESMTP id 5C1FB8D0032 for ; Tue, 19 Apr 2022 00:50:58 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 367EF554 for ; Tue, 19 Apr 2022 04:50:58 +0000 (UTC) X-FDA: 79372403796.24.90962BD Received: from heian.cn.fujitsu.com (mail.cn.fujitsu.com [183.91.158.132]) by imf03.hostedemail.com (Postfix) with ESMTP id 58D5520002 for ; Tue, 19 Apr 2022 04:50:56 +0000 (UTC) IronPort-Data: A9a23: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 IronPort-HdrOrdr: A9a23:C2Iz5KkhL7hgpqneNOUWESz0vxPpDfLK3DAbv31ZSRFFG/Fxl6iV/cjzsiWE8Qr5OUtQ4exoV5PwIk80maQb3WBVB8bHYOCEghrPEGgB1/qB/9SIIUSXnYQxuZuIMZIOb+EYZmIbsS+V2meF+q4bsby6Gb6T9Jvj5kYoXQd3cLth8gs8Lg6aF3d9TA5ACYFRLuvn2uN34yqnZW8Mbtm2Ql0MX+34rdXNk578JTEcARpP0njysRqYrK79DwOD3goTFxdGwbIZ+2DDlADjooWP2svLsSPh6w== X-IronPort-AV: E=Sophos;i="5.88,333,1635177600"; d="scan'208";a="123671754" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 19 Apr 2022 12:50:54 +0800 Received: from G08CNEXMBPEKD04.g08.fujitsu.local (unknown [10.167.33.201]) by cn.fujitsu.com (Postfix) with ESMTP id 97B7E4D17170; Tue, 19 Apr 2022 12:50:50 +0800 (CST) Received: from G08CNEXJMPEKD02.g08.fujitsu.local (10.167.33.202) by G08CNEXMBPEKD04.g08.fujitsu.local (10.167.33.201) with Microsoft SMTP Server (TLS) id 15.0.1497.23; Tue, 19 Apr 2022 12:50:52 +0800 Received: from G08CNEXCHPEKD09.g08.fujitsu.local (10.167.33.85) by G08CNEXJMPEKD02.g08.fujitsu.local (10.167.33.202) with Microsoft SMTP Server (TLS) id 15.0.1497.23; Tue, 19 Apr 2022 12:50:51 +0800 Received: from irides.mr.mr (10.167.225.141) by G08CNEXCHPEKD09.g08.fujitsu.local (10.167.33.209) with Microsoft SMTP Server id 15.0.1497.23 via Frontend Transport; Tue, 19 Apr 2022 12:50:48 +0800 From: Shiyang Ruan To: , , , , CC: , , , , , Christoph Hellwig Subject: [PATCH v13 4/7] fsdax: Introduce dax_lock_mapping_entry() Date: Tue, 19 Apr 2022 12:50:42 +0800 Message-ID: <20220419045045.1664996-5-ruansy.fnst@fujitsu.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220419045045.1664996-1-ruansy.fnst@fujitsu.com> References: <20220419045045.1664996-1-ruansy.fnst@fujitsu.com> MIME-Version: 1.0 X-yoursite-MailScanner-ID: 97B7E4D17170.AEC08 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: ruansy.fnst@fujitsu.com X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 58D5520002 X-Rspam-User: Authentication-Results: imf03.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=fujitsu.com (policy=none); spf=none (imf03.hostedemail.com: domain of ruansy.fnst@fujitsu.com has no SPF policy when checking 183.91.158.132) smtp.mailfrom=ruansy.fnst@fujitsu.com X-Stat-Signature: 3xwdbyhm7awo1x1htnncs1xfwbxa1omx X-HE-Tag: 1650343856-799618 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: The current dax_lock_page() locks dax entry by obtaining mapping and index in page. To support 1-to-N RMAP in NVDIMM, we need a new function to lock a specific dax entry corresponding to this file's mapping,index. And output the page corresponding to the specific dax entry for caller use. Signed-off-by: Shiyang Ruan Reviewed-by: Christoph Hellwig Reviewed-by: Darrick J. Wong --- fs/dax.c | 63 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/dax.h | 15 +++++++++++ 2 files changed, 78 insertions(+) diff --git a/fs/dax.c b/fs/dax.c index 1ac12e877f4f..57efd3f73655 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -455,6 +455,69 @@ void dax_unlock_page(struct page *page, dax_entry_t cookie) dax_unlock_entry(&xas, (void *)cookie); } +/* + * dax_lock_mapping_entry - Lock the DAX entry corresponding to a mapping + * @mapping: the file's mapping whose entry we want to lock + * @index: the offset within this file + * @page: output the dax page corresponding to this dax entry + * + * Return: A cookie to pass to dax_unlock_mapping_entry() or 0 if the entry + * could not be locked. + */ +dax_entry_t dax_lock_mapping_entry(struct address_space *mapping, pgoff_t index, + struct page **page) +{ + XA_STATE(xas, NULL, 0); + void *entry; + + rcu_read_lock(); + for (;;) { + entry = NULL; + if (!dax_mapping(mapping)) + break; + + xas.xa = &mapping->i_pages; + xas_lock_irq(&xas); + xas_set(&xas, index); + entry = xas_load(&xas); + if (dax_is_locked(entry)) { + rcu_read_unlock(); + wait_entry_unlocked(&xas, entry); + rcu_read_lock(); + continue; + } + if (!entry || + dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { + /* + * Because we are looking for entry from file's mapping + * and index, so the entry may not be inserted for now, + * or even a zero/empty entry. We don't think this is + * an error case. So, return a special value and do + * not output @page. + */ + entry = (void *)~0UL; + } else { + *page = pfn_to_page(dax_to_pfn(entry)); + dax_lock_entry(&xas, entry); + } + xas_unlock_irq(&xas); + break; + } + rcu_read_unlock(); + return (dax_entry_t)entry; +} + +void dax_unlock_mapping_entry(struct address_space *mapping, pgoff_t index, + dax_entry_t cookie) +{ + XA_STATE(xas, &mapping->i_pages, index); + + if (cookie == ~0UL) + return; + + dax_unlock_entry(&xas, (void *)cookie); +} + /* * Find page cache entry at given index. If it is a DAX entry, return it * with the entry locked. If the page cache doesn't contain an entry at diff --git a/include/linux/dax.h b/include/linux/dax.h index 9c426a207ba8..c152f315d1c9 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -143,6 +143,10 @@ struct page *dax_layout_busy_page(struct address_space *mapping); struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end); dax_entry_t dax_lock_page(struct page *page); void dax_unlock_page(struct page *page, dax_entry_t cookie); +dax_entry_t dax_lock_mapping_entry(struct address_space *mapping, + unsigned long index, struct page **page); +void dax_unlock_mapping_entry(struct address_space *mapping, + unsigned long index, dax_entry_t cookie); #else static inline struct page *dax_layout_busy_page(struct address_space *mapping) { @@ -170,6 +174,17 @@ static inline dax_entry_t dax_lock_page(struct page *page) static inline void dax_unlock_page(struct page *page, dax_entry_t cookie) { } + +static inline dax_entry_t dax_lock_mapping_entry(struct address_space *mapping, + unsigned long index, struct page **page) +{ + return 0; +} + +static inline void dax_unlock_mapping_entry(struct address_space *mapping, + unsigned long index, dax_entry_t cookie) +{ +} #endif int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,