From patchwork Fri Mar 2 19:06:36 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10255527 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id EBFA46037D for ; Fri, 2 Mar 2018 19:15:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DB2E92823E for ; Fri, 2 Mar 2018 19:15:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CF3662832D; Fri, 2 Mar 2018 19:15:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2E92E2823E for ; Fri, 2 Mar 2018 19:15:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1426347AbeCBTPo (ORCPT ); Fri, 2 Mar 2018 14:15:44 -0500 Received: from mga06.intel.com ([134.134.136.31]:4817 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423640AbeCBTPn (ORCPT ); Fri, 2 Mar 2018 14:15:43 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Mar 2018 11:15:42 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.47,413,1515484800"; d="scan'208";a="22401525" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by orsmga006.jf.intel.com with ESMTP; 02 Mar 2018 11:15:42 -0800 Subject: [PATCH v6] dax: introduce IS_DEVDAX() and IS_FSDAX() From: Dan Williams To: linux-nvdimm@lists.01.org Cc: Theodore Ts'o , Andreas Dilger , Alexander Viro , "Darrick J. Wong" , linux-xfs@vger.kernel.org, Matthew Wilcox , Ross Zwisler , stable@vger.kernel.org, Jan Kara , Jan Kara , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org Date: Fri, 02 Mar 2018 11:06:36 -0800 Message-ID: <152001757529.22146.17936438768625217740.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: References: User-Agent: StGit/0.18-2-gc94f MIME-Version: 1.0 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The current IS_DAX() helper that checks if a file is in DAX mode serves two purposes. It is a control flow branch condition for DAX vs non-DAX paths and it is a mechanism to perform dead code elimination. The dead code elimination is required in the CONFIG_FS_DAX=n case since there are symbols in fs/dax.c that will be elided. While the dead code elimination can be addressed with nop stubs for the fs/dax.c symbols that does not address the need for a DAX control flow helper where fs/dax.c symbols are not involved. Moreover, the control flow changes, in some cases, need to be cognizant of whether the DAX file is a typical file or a Device-DAX special file. Introduce IS_DEVDAX() and IS_FSDAX() to simultaneously address the file-type control flow and dead-code elimination use cases. IS_DAX() will be deleted after all sites are converted to use the file-type specific helper. Note, this change is also a pre-requisite for fixing the definition of the S_DAX inode flag in the CONFIG_FS_DAX=n + CONFIG_DEV_DAX=y case. The flag needs to be defined, non-zero, if either DAX facility is enabled. Cc: "Theodore Ts'o" Cc: Andreas Dilger Cc: Alexander Viro Cc: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org Cc: Matthew Wilcox Cc: Ross Zwisler Cc: Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Reported-by: Jan Kara Reviewed-by: Jan Kara Signed-off-by: Dan Williams Reviewed-by: Darrick J. Wong --- Changes since v5: * add comments to clarify the S_ISCHR() checks (Darrick) include/linux/fs.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/include/linux/fs.h b/include/linux/fs.h index 79c413985305..751975b8b29b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1909,6 +1909,30 @@ static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags #define IS_WHITEOUT(inode) (S_ISCHR(inode->i_mode) && \ (inode)->i_rdev == WHITEOUT_DEV) +static inline bool IS_DEVDAX(struct inode *inode) +{ + if (!IS_ENABLED(CONFIG_DEV_DAX)) + return false; + if ((inode->i_flags & S_DAX) == 0) + return false; + /* regular files with S_DAX are filesystem-dax instances */ + if (!S_ISCHR(inode->i_mode)) + return false; + return true; +} + +static inline bool IS_FSDAX(struct inode *inode) +{ + if (!IS_ENABLED(CONFIG_FS_DAX)) + return false; + if ((inode->i_flags & S_DAX) == 0) + return false; + /* character devices with S_DAX are device-dax instances */ + if (S_ISCHR(inode->i_mode)) + return false; + return true; +} + static inline bool HAS_UNMAPPED_ID(struct inode *inode) { return !uid_valid(inode->i_uid) || !gid_valid(inode->i_gid);