From patchwork Thu Mar 2 04:32:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Imran Khan X-Patchwork-Id: 13156678 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE088C7EE2F for ; Thu, 2 Mar 2023 04:32:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229745AbjCBEc2 (ORCPT ); Wed, 1 Mar 2023 23:32:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58278 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229739AbjCBEc0 (ORCPT ); Wed, 1 Mar 2023 23:32:26 -0500 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0581C4A1FC; Wed, 1 Mar 2023 20:32:23 -0800 (PST) Received: from pps.filterd (m0246617.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 321MuxpR010778; Thu, 2 Mar 2023 04:32:20 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2022-7-12; bh=YN/Ch07oSsUOLr3lFWqb7Mfe8tp5H4NhoNi2kvbRIPc=; b=s//Pg01Sz8r4OWSXfIpCwmdlGJzXXlfDsHX3/dZyRC9uqemlp7j7tegI4ZtctDyjGEVz Ec6iXuTKnE74uxEzl3A42ToGB5BX4OERHD0ujGXLBYoo5vQtd3puQewV6D5YQKj7Ziqj jO3dfZelirwJfzoocqtM63rwxo7xYbF55uwqlNC8o7DrXiu3XENm3ZsdkPGfR7fqeLaG OSnws33h+/nw8tNeTUabXfcBx0G/R2lU3Kf7FEt0y9exTwE0wSnGIZKYtrPdI6ihTe/C Zd+EWxsTSLyDhL3zrN5iG9UFu75EvmHFajXwr6UgS6jfgCLHlJx9FImmarT+/1VQnM8I Bw== Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.appoci.oracle.com [147.154.18.20]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3nybb2jnhu-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 02 Mar 2023 04:32:20 +0000 Received: from pps.filterd (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (8.17.1.5/8.17.1.5) with ESMTP id 3222fxjh031538; Thu, 2 Mar 2023 04:32:18 GMT Received: from pps.reinject (localhost [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 3ny8sga7hq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 02 Mar 2023 04:32:18 +0000 Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 3224W8eY012677; Thu, 2 Mar 2023 04:32:18 GMT Received: from localhost.localdomain (dhcp-10-191-129-161.vpn.oracle.com [10.191.129.161]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTP id 3ny8sga7bn-4; Thu, 02 Mar 2023 04:32:17 +0000 From: Imran Khan To: tj@kernel.org, gregkh@linuxfoundation.org, viro@zeniv.linux.org.uk Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, joe.jin@oracle.com Subject: [PATCH 3/3] kernfs: change kernfs_rename_lock into a read-write lock. Date: Thu, 2 Mar 2023 15:32:03 +1100 Message-Id: <20230302043203.1695051-4-imran.f.khan@oracle.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230302043203.1695051-1-imran.f.khan@oracle.com> References: <20230302043203.1695051-1-imran.f.khan@oracle.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-03-02_01,2023-03-01_03,2023-02-09_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 mlxlogscore=999 mlxscore=0 adultscore=0 bulkscore=0 malwarescore=0 phishscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2303020035 X-Proofpoint-GUID: KApAJvKGxjQeBdVv7hOdaI69gaix-Q-T X-Proofpoint-ORIG-GUID: KApAJvKGxjQeBdVv7hOdaI69gaix-Q-T Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org kernfs_rename_lock protects a node's ->parent and thus kernfs topology. Thus it can be used in cases that rely on a stable kernfs topology. Change it to a read-write lock for better scalability. Suggested by: Al Viro Signed-off-by: Imran Khan Reviewed-by: Matthew Wilcox (Oracle) --- fs/kernfs/dir.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 2cdb8516e5287..06e27b36216fe 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -17,7 +17,7 @@ #include "kernfs-internal.h" -static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */ +static DEFINE_RWLOCK(kernfs_rename_lock); /* kn->parent and ->name */ /* * Don't use rename_lock to piggy back on pr_cont_buf. We don't want to * call pr_cont() while holding rename_lock. Because sometimes pr_cont() @@ -196,9 +196,9 @@ int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen) unsigned long flags; int ret; - spin_lock_irqsave(&kernfs_rename_lock, flags); + read_lock_irqsave(&kernfs_rename_lock, flags); ret = kernfs_name_locked(kn, buf, buflen); - spin_unlock_irqrestore(&kernfs_rename_lock, flags); + read_unlock_irqrestore(&kernfs_rename_lock, flags); return ret; } @@ -224,9 +224,9 @@ int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from, unsigned long flags; int ret; - spin_lock_irqsave(&kernfs_rename_lock, flags); + read_lock_irqsave(&kernfs_rename_lock, flags); ret = kernfs_path_from_node_locked(to, from, buf, buflen); - spin_unlock_irqrestore(&kernfs_rename_lock, flags); + read_unlock_irqrestore(&kernfs_rename_lock, flags); return ret; } EXPORT_SYMBOL_GPL(kernfs_path_from_node); @@ -294,10 +294,10 @@ struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn) struct kernfs_node *parent; unsigned long flags; - spin_lock_irqsave(&kernfs_rename_lock, flags); + read_lock_irqsave(&kernfs_rename_lock, flags); parent = kn->parent; kernfs_get(parent); - spin_unlock_irqrestore(&kernfs_rename_lock, flags); + read_unlock_irqrestore(&kernfs_rename_lock, flags); return parent; } @@ -1731,7 +1731,7 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, kernfs_get(new_parent); /* rename_lock protects ->parent and ->name accessors */ - spin_lock_irq(&kernfs_rename_lock); + write_lock_irq(&kernfs_rename_lock); old_parent = kn->parent; kn->parent = new_parent; @@ -1742,7 +1742,7 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, kn->name = new_name; } - spin_unlock_irq(&kernfs_rename_lock); + write_unlock_irq(&kernfs_rename_lock); kn->hash = kernfs_name_hash(kn->name, kn->ns); kernfs_link_sibling(kn);