[PATCH v7 6/6] kernfs: dont call d_splice_alias() under kernfs node lock

From: Ian Kent
Date: Tue Jun 15 2021 - 06:27:29 EST


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@xxxxxxxxxx>
Reviewed-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
---
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,