smb/server: use lookup_one_unlocked()

In process_query_dir_entries(), instead of locking the directory,
performing a lookup, then unlocking, we can simply call
lookup_one_unlocked().  That takes locks the directory only when needed.

This removes the only users of lock_dir() and unlock_dir() so they can
be removed.

Signed-off-by: NeilBrown <neil@brown.name>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: neilbrown

fs/smb/server/smb2pdu.c

@@ -4108,20 +4108,6 @@ struct smb2_query_dir_private {
 	int			info_level;
 };
 
-static void lock_dir(struct ksmbd_file *dir_fp)
-{
-	struct dentry *dir = dir_fp->filp->f_path.dentry;
-
-	inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
-}
-
-static void unlock_dir(struct ksmbd_file *dir_fp)
-{
-	struct dentry *dir = dir_fp->filp->f_path.dentry;
-
-	inode_unlock(d_inode(dir));
-}
-
 static int process_query_dir_entries(struct smb2_query_dir_private *priv)
 {
 	struct mnt_idmap	*idmap = file_mnt_idmap(priv->dir_fp->filp);
@@ -4136,12 +4122,10 @@ static int process_query_dir_entries(struct smb2_query_dir_private *priv)
 		if (dentry_name(priv->d_info, priv->info_level))
 			return -EINVAL;
 
-		lock_dir(priv->dir_fp);
-		dent = lookup_one(idmap,
-				  &QSTR_LEN(priv->d_info->name,
-					    priv->d_info->name_len),
-				  priv->dir_fp->filp->f_path.dentry);
-		unlock_dir(priv->dir_fp);
+		dent = lookup_one_unlocked(idmap,
+					   &QSTR_LEN(priv->d_info->name,
+						     priv->d_info->name_len),
+					   priv->dir_fp->filp->f_path.dentry);
 
 		if (IS_ERR(dent)) {
 			ksmbd_debug(SMB, "Cannot lookup `%s' [%ld]\n",