[PATCH 17/19] init: factor out root device lookup into lookup_root_device()

[Vincent Mailhol <mailhol@kernel.org>]

DPS root detection will also need to work if root_wait is set, meaning
that wait_for_root() needs to handle the DPS logic.

Move early_lookup_bdev() out of wait_for_root() into the new
lookup_root_device() so later changes can extend the lookup policy
without duplicating the retry logic.

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
---
 init/do_mounts.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/init/do_mounts.c b/init/do_mounts.c
index 95e0b3a0f711..5fb5aeb88da9 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -402,6 +402,11 @@ void __init mount_root(char *root_device_name)
 	}
 }
 
+static int __init lookup_root_device(char *root_device_name)
+{
+	return early_lookup_bdev(root_device_name, &ROOT_DEV);
+}
+
 /* wait for any asynchronous scanning to complete */
 static void __init wait_for_root(char *root_device_name)
 {
@@ -415,7 +420,7 @@ static void __init wait_for_root(char *root_device_name)
 	end = ktime_add_ms(ktime_get_raw(), root_wait);
 
 	while (!driver_probe_done() ||
-	       early_lookup_bdev(root_device_name, &ROOT_DEV) < 0) {
+	       lookup_root_device(root_device_name) < 0) {
 		msleep(5);
 		if (root_wait > 0 && ktime_after(ktime_get_raw(), end))
 			break;

-- 
2.53.0