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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY autolearn=ham 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 E85FEC433DF for ; Mon, 12 Oct 2020 21:28:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A13F52145D for ; Mon, 12 Oct 2020 21:28:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="qUgIOMoc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729782AbgJLV2Y (ORCPT ); Mon, 12 Oct 2020 17:28:24 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:49362 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729761AbgJLV2X (ORCPT ); Mon, 12 Oct 2020 17:28:23 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09CLEEKC034160; Mon, 12 Oct 2020 21:28:21 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2020-01-29; bh=UAnGm5JzYKr7D/1aRkhxjAYsWYjSoOGfJNbuADtBquE=; b=qUgIOMocWmVnPUpu74ODO1jk1J7bxYrkh9GB2sGPSjYoJP7ODGJQWi5r44vkD7Be7EsK UU/sn9Z8Lwe+I3NnEIKuIsT38o5Z2MnGFOHFK0dSo8G/yCbSyKVqXeUyD0llfyfwlUBt GY/uat2Y7TCExFB2XRr+t2qVnkdIWPsvy7M9XEsOO+7yGw/+Z997GXHFPinxc9a8dEpj jgqY8+9tjxLBwQIsWAMatYGflbQ/eKytH2uocpGyxBvNRtq8RgI2NlMZiHE5T6GxNhER o3cTb7XrwwRhVxrssCcvOE4wna1Aawf56YeEc0mjhLxmz7m7JgPso+FWfYPy1eeNihUj Uw== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2120.oracle.com with ESMTP id 3434wkf7cw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 12 Oct 2020 21:28:21 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09CLBUP8088279; Mon, 12 Oct 2020 21:28:20 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3020.oracle.com with ESMTP id 344by1a0up-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 12 Oct 2020 21:28:20 +0000 Received: from abhmp0011.oracle.com (abhmp0011.oracle.com [141.146.116.17]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 09CLSJo8006386; Mon, 12 Oct 2020 21:28:19 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 12 Oct 2020 14:28:19 -0700 Date: Mon, 12 Oct 2020 14:28:18 -0700 From: "Darrick J. Wong" To: Brian Foster Cc: Pavel Reichl , linux-xfs@vger.kernel.org Subject: Re: [PATCH v11 1/4] xfs: Refactor xfs_isilocked() Message-ID: <20201012212818.GX6540@magnolia> References: <20201009195515.82889-1-preichl@redhat.com> <20201009195515.82889-2-preichl@redhat.com> <20201012160308.GH917726@bfoster> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201012160308.GH917726@bfoster> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9772 signatures=668681 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 spamscore=0 suspectscore=1 mlxscore=0 malwarescore=0 adultscore=0 bulkscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010120160 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9772 signatures=668681 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 lowpriorityscore=0 mlxscore=0 malwarescore=0 phishscore=0 suspectscore=1 impostorscore=0 clxscore=1015 spamscore=0 priorityscore=1501 bulkscore=0 adultscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010120160 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Mon, Oct 12, 2020 at 12:03:08PM -0400, Brian Foster wrote: > On Fri, Oct 09, 2020 at 09:55:12PM +0200, Pavel Reichl wrote: > > Refactor xfs_isilocked() to use newly introduced __xfs_rwsem_islocked(). > > __xfs_rwsem_islocked() is a helper function which encapsulates checking > > state of rw_semaphores hold by inode. > > > > Signed-off-by: Pavel Reichl > > Suggested-by: Dave Chinner > > Suggested-by: Eric Sandeen > > Suggested-by: Darrick J. Wong > > Reviewed-by: Darrick J. Wong > > --- > > fs/xfs/xfs_inode.c | 48 ++++++++++++++++++++++++++++++++++++++-------- > > fs/xfs/xfs_inode.h | 21 +++++++++++++------- > > 2 files changed, 54 insertions(+), 15 deletions(-) > > > > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c > > index c06129cffba9..7c1ceb4df4ec 100644 > > --- a/fs/xfs/xfs_inode.c > > +++ b/fs/xfs/xfs_inode.c > > @@ -345,9 +345,43 @@ xfs_ilock_demote( > > } > > > > #if defined(DEBUG) || defined(XFS_WARN) > > -int > > +static inline bool > > +__xfs_rwsem_islocked( > > + struct rw_semaphore *rwsem, > > + int lock_flags) > > +{ > > + int arg; > > + > > + if (!debug_locks) > > + return rwsem_is_locked(rwsem); > > + > > + if (lock_flags & (1 << XFS_SHARED_LOCK_SHIFT)) { > > + /* > > + * The caller could be asking if we have (shared | excl) > > + * access to the lock. Ask lockdep if the rwsem is > > + * locked either for read or write access. > > + * > > + * The caller could also be asking if we have only > > + * shared access to the lock. Holding a rwsem > > + * write-locked implies read access as well, so the > > + * request to lockdep is the same for this case. > > + */ > > + arg = -1; > > + } else { > > + /* > > + * The caller is asking if we have only exclusive access > > + * to the lock. Ask lockdep if the rwsem is locked for > > + * write access. > > + */ > > + arg = 0; > > + } > > Are these arg values documented somewhere? A quick look at the function > below didn't show anything.. Alas, no. :( If you trace lockdep_is_held_type -> lock_is_held_type -> __lock_is_held then you'll notice that "if (read == -1" bit, but none of those functions are documented. So I have no if that's /really/ permanent, other than to say that it exists because Dave and Christoph and I requested it years ago and commit f8319483f57f1 has been unchanged since 2016. --D > Also, I find the pattern of shifting in the caller slightly confusing, > particularly with the 'lock_flags' name being passed down through the > caller. Any reason we couldn't pass the shift value as a parameter and > do the shift at the top of the function so the logic is clear and in one > place? > > > + > > + return lockdep_is_held_type(rwsem, arg); > > +} > > + > > +bool > > xfs_isilocked( > > - xfs_inode_t *ip, > > + struct xfs_inode *ip, > > uint lock_flags) > > { > > if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) { > ... > > diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h > > index e9a8bb184d1f..77776af75c77 100644 > > --- a/fs/xfs/xfs_inode.h > > +++ b/fs/xfs/xfs_inode.h > > @@ -268,12 +268,19 @@ static inline void xfs_ifunlock(struct xfs_inode *ip) > > * Bit ranges: 1<<1 - 1<<16-1 -- iolock/ilock modes (bitfield) > > * 1<<16 - 1<<32-1 -- lockdep annotation (integers) > > */ > > -#define XFS_IOLOCK_EXCL (1<<0) > > -#define XFS_IOLOCK_SHARED (1<<1) > > -#define XFS_ILOCK_EXCL (1<<2) > > -#define XFS_ILOCK_SHARED (1<<3) > > -#define XFS_MMAPLOCK_EXCL (1<<4) > > -#define XFS_MMAPLOCK_SHARED (1<<5) > > + > > +#define XFS_IOLOCK_FLAG_SHIFT 0 > > +#define XFS_ILOCK_FLAG_SHIFT 2 > > +#define XFS_MMAPLOCK_FLAG_SHIFT 4 > > + > > +#define XFS_SHARED_LOCK_SHIFT 1 > > + > > +#define XFS_IOLOCK_EXCL (1 << (XFS_IOLOCK_FLAG_SHIFT)) > > +#define XFS_IOLOCK_SHARED (XFS_IOLOCK_EXCL << (XFS_SHARED_LOCK_SHIFT)) > > +#define XFS_ILOCK_EXCL (1 << (XFS_ILOCK_FLAG_SHIFT)) > > +#define XFS_ILOCK_SHARED (XFS_ILOCK_EXCL << (XFS_SHARED_LOCK_SHIFT)) > > +#define XFS_MMAPLOCK_EXCL (1 << (XFS_MMAPLOCK_FLAG_SHIFT)) > > +#define XFS_MMAPLOCK_SHARED (XFS_MMAPLOCK_EXCL << (XFS_SHARED_LOCK_SHIFT)) > > > > Any reason for the extra params around the shift values? > > Brian > > > #define XFS_LOCK_MASK (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED \ > > | XFS_ILOCK_EXCL | XFS_ILOCK_SHARED \ > > @@ -412,7 +419,7 @@ void xfs_ilock(xfs_inode_t *, uint); > > int xfs_ilock_nowait(xfs_inode_t *, uint); > > void xfs_iunlock(xfs_inode_t *, uint); > > void xfs_ilock_demote(xfs_inode_t *, uint); > > -int xfs_isilocked(xfs_inode_t *, uint); > > +bool xfs_isilocked(struct xfs_inode *, uint); > > uint xfs_ilock_data_map_shared(struct xfs_inode *); > > uint xfs_ilock_attr_map_shared(struct xfs_inode *); > > > > -- > > 2.26.2 > > >