From patchwork Wed Jun 9 08:52:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ian Kent X-Patchwork-Id: 12309317 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 B95DBC47095 for ; Wed, 9 Jun 2021 08:52:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A4F4061263 for ; Wed, 9 Jun 2021 08:52:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237826AbhFIIyt convert rfc822-to-8bit (ORCPT ); Wed, 9 Jun 2021 04:54:49 -0400 Received: from us-smtp-delivery-44.mimecast.com ([205.139.111.44]:52286 "EHLO us-smtp-delivery-44.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237818AbhFIIyr (ORCPT ); Wed, 9 Jun 2021 04:54:47 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-280-8y1QuQ0oMTu7V5NPd0r9VA-1; Wed, 09 Jun 2021 04:52:49 -0400 X-MC-Unique: 8y1QuQ0oMTu7V5NPd0r9VA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1D299801B16; Wed, 9 Jun 2021 08:52:48 +0000 (UTC) Received: from web.messagingengine.com (ovpn-116-20.sin2.redhat.com [10.67.116.20]) by smtp.corp.redhat.com (Postfix) with ESMTP id B73145D9E2; Wed, 9 Jun 2021 08:52:26 +0000 (UTC) Subject: [PATCH v6 7/7] kernfs: dont call d_splice_alias() under kernfs node lock From: Ian Kent To: Greg Kroah-Hartman , Tejun Heo Cc: Eric Sandeen , Fox Chen , Brice Goglin , Al Viro , Rick Lindsley , David Howells , Miklos Szeredi , Marcelo Tosatti , "Eric W. Biederman" , Carlos Maiolino , linux-fsdevel , Kernel Mailing List Date: Wed, 09 Jun 2021 16:52:25 +0800 Message-ID: <162322874509.361452.3143376113190093370.stgit@web.messagingengine.com> In-Reply-To: <162322846765.361452.17051755721944717990.stgit@web.messagingengine.com> References: <162322846765.361452.17051755721944717990.stgit@web.messagingengine.com> User-Agent: StGit/0.23 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=raven@themaw.net X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: themaw.net Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The call to d_splice_alias() in kernfs_iop_lookup() doesn't depend on any kernfs node so there's no reason to hold the kernfs node lock when calling it. Signed-off-by: Ian Kent Reviewed-by: Miklos Szeredi --- fs/kernfs/dir.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 195561c08439a..a5820a8c139a2 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -1097,7 +1097,6 @@ static struct dentry *kernfs_iop_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { - struct dentry *ret; struct kernfs_node *parent = dir->i_private; struct kernfs_node *kn; struct inode *inode = NULL; @@ -1117,11 +1116,10 @@ static struct dentry *kernfs_iop_lookup(struct inode *dir, /* Needed only for negative dentry validation */ if (!inode) kernfs_set_rev(parent, dentry); - /* instantiate and hash (possibly negative) dentry */ - ret = d_splice_alias(inode, dentry); up_read(&kernfs_rwsem); - return ret; + /* instantiate and hash (possibly negative) dentry */ + return d_splice_alias(inode, dentry); } static int kernfs_iop_mkdir(struct user_namespace *mnt_userns,