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From: Ian Kent <raven@themaw.net>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tejun Heo <tj@kernel.org>
Cc: Eric Sandeen <sandeen@sandeen.net>,
	Fox Chen <foxhlchen@gmail.com>,
	Brice Goglin <brice.goglin@gmail.com>,
	Al Viro <viro@ZenIV.linux.org.uk>,
	Rick Lindsley <ricklind@linux.vnet.ibm.com>,
	David Howells <dhowells@redhat.com>,
	Miklos Szeredi <miklos@szeredi.hu>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Carlos Maiolino <cmaiolino@redhat.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [PATCH v7 6/6] kernfs: dont call d_splice_alias() under kernfs node lock
Date: Tue, 15 Jun 2021 18:27:06 +0800	[thread overview]
Message-ID: <162375282484.232295.17118280961409351125.stgit@web.messagingengine.com> (raw)
In-Reply-To: <162375263398.232295.14755578426619198534.stgit@web.messagingengine.com>

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 <raven@themaw.net>
Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
---
 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 a5080fb1dfc05..723348607033c 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,



  parent reply	other threads:[~2021-06-15 10:27 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-15 10:25 [PATCH v7 0/6] kernfs: proposed locking and concurrency improvement Ian Kent
2021-06-15 10:25 ` [PATCH v7 1/6] kernfs: move revalidate to be near lookup Ian Kent
2021-06-15 15:06   ` Greg Kroah-Hartman
2021-06-15 10:26 ` [PATCH v7 2/6] kernfs: add a revision to identify directory node changes Ian Kent
2021-06-16  9:11   ` Miklos Szeredi
2021-06-15 10:26 ` [PATCH v7 3/6] kernfs: use VFS negative dentry caching Ian Kent
2021-06-16  9:12   ` Miklos Szeredi
2021-06-15 10:26 ` [PATCH v7 4/6] kernfs: switch kernfs to use an rwsem Ian Kent
2021-06-15 10:26 ` [PATCH v7 5/6] kernfs: use i_lock to protect concurrent inode updates Ian Kent
2021-06-15 10:27 ` Ian Kent [this message]
2021-06-15 10:39 ` [PATCH v7 0/6] kernfs: proposed locking and concurrency improvement Ian Kent

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