autofs: refactor autofs_prepare_pipe()

Refactor autofs_prepare_pipe() by seperating out a check function
to be used later.
Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>
Message-Id: <20230922041215.13675-2-raven@themaw.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/autofs/autofs_i.h

@@ -209,12 +209,20 @@ int autofs_fill_super(struct super_block *, void *, int);
 struct autofs_info *autofs_new_ino(struct autofs_sb_info *);
 void autofs_clean_ino(struct autofs_info *);
 
-static inline int autofs_prepare_pipe(struct file *pipe)
+static inline int autofs_check_pipe(struct file *pipe)
 {
 	if (!(pipe->f_mode & FMODE_CAN_WRITE))
 		return -EINVAL;
 	if (!S_ISFIFO(file_inode(pipe)->i_mode))
 		return -EINVAL;
+	return 0;
+}
+
+static inline int autofs_prepare_pipe(struct file *pipe)
+{
+	int ret = autofs_check_pipe(pipe);
+	if (ret < 0)
+		return ret;
 	/* We want a packet pipe */
 	pipe->f_flags |= O_DIRECT;
 	/* We don't expect -EAGAIN */