From patchwork Thu Mar 9 11:09:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Imran Khan X-Patchwork-Id: 13167251 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 BE009C64EC4 for ; Thu, 9 Mar 2023 11:15:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229702AbjCILPP (ORCPT ); Thu, 9 Mar 2023 06:15:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231473AbjCILOf (ORCPT ); Thu, 9 Mar 2023 06:14:35 -0500 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6364AF24A1; Thu, 9 Mar 2023 03:09:52 -0800 (PST) Received: from pps.filterd (m0246627.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3297ehhf018305; Thu, 9 Mar 2023 11:09:48 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=sM2f8KUGw2ieEok7xffWn1NRPRHy+6lIt8O7z1nqwUA=; b=TSnSEGn5fb0r5OLvOmUoycnnvxGcMtkvj/9K5fXfjPDk9H8e+BsRTw2uEkMU64l1vELt aKRdI2H/G4dZsIpo3IJXtA0+sTk8iJzlIig9WYSj42yiRC20iPnTLAfw7xbxFk4NGbsv fAUU1a0c9ZPPgIOYiCw0zCAnLYMpgsH90fLJ4ilnFoqXLDpeP+0PxTuAJ8Ka31WQUpKD BSQ1H4dQ7EgM8MFHSHQNhxHF2vEp/QZLOagIHzUsYu/NtfarilnJfAQ1za8URmfhtyeU aWG/rkqYpVFuOzgPtj5XzP90WmFP17XqbXdCEgdU+QlDiVNQamF5pJCX1cuYikzzwo4B ig== Received: from phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta02.appoci.oracle.com [147.154.114.232]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3p5nn96r6y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 09 Mar 2023 11:09:48 +0000 Received: from pps.filterd (phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (8.17.1.5/8.17.1.5) with ESMTP id 3299XM3J020822; Thu, 9 Mar 2023 11:09:47 GMT Received: from pps.reinject (localhost [127.0.0.1]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 3p6fu9b78j-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 09 Mar 2023 11:09:47 +0000 Received: from phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 329B70tO021817; Thu, 9 Mar 2023 11:09:46 GMT Received: from localhost.localdomain (dhcp-10-191-129-247.vpn.oracle.com [10.191.129.247]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTP id 3p6fu9b73f-4; Thu, 09 Mar 2023 11:09:46 +0000 From: Imran Khan To: tj@kernel.org, gregkh@linuxfoundation.org, viro@zeniv.linux.org.uk, willy@infradead.org Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, joe.jin@oracle.com Subject: [PATCH v2 3/3] kernfs: change kernfs_rename_lock into a read-write lock. Date: Thu, 9 Mar 2023 22:09:32 +1100 Message-Id: <20230309110932.2889010-4-imran.f.khan@oracle.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230309110932.2889010-1-imran.f.khan@oracle.com> References: <20230309110932.2889010-1-imran.f.khan@oracle.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-03-09_06,2023-03-08_03,2023-02-09_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 adultscore=0 phishscore=0 suspectscore=0 malwarescore=0 spamscore=0 bulkscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2303090088 X-Proofpoint-GUID: ZO8p4MktoRctYaJuWOGPKLN1rJZ9us9T X-Proofpoint-ORIG-GUID: ZO8p4MktoRctYaJuWOGPKLN1rJZ9us9T 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 Reviewed-by: Matthew Wilcox (Oracle) Signed-off-by: Imran Khan --- 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);