devtmpfs: factor out setup part of devtmpfsd()

Factor out the setup part of devtmpfsd() to make it a bit easier to
see that we always call setup_done() exactly once (provided of course
the kthread is succesfully created).
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20200115184154.3492-3-linux@rasmusvillemoes.dkSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/devtmpfs.c

@@ -388,7 +388,7 @@ static int handle(const char *name, umode_t mode, kuid_t uid, kgid_t gid,
 		return handle_remove(name, dev);
 }
 
-static int devtmpfsd(void *p)
+static int devtmpfs_setup(void *p)
 {
 	int err;
 
@@ -400,7 +400,18 @@ static int devtmpfsd(void *p)
 		goto out;
 	ksys_chdir("/.."); /* will traverse into overmounted root */
 	ksys_chroot(".");
+out:
+	*(int *)p = err;
 	complete(&setup_done);
+	return err;
+}
+
+static int devtmpfsd(void *p)
+{
+	int err = devtmpfs_setup(p);
+
+	if (err)
+		return err;
 	while (1) {
 		spin_lock(&req_lock);
 		while (requests) {
@@ -421,10 +432,6 @@ static int devtmpfsd(void *p)
 		schedule();
 	}
 	return 0;
-out:
-	*(int *)p = err;
-	complete(&setup_done);
-	return err;
 }
 
 /*