init: wait for partition and retry scan

As Clear Linux boots fast the device is not ready when
the mounting code is reached, so a retry device scan will
be performed every 0.5 sec for at least 40 sec
and synchronize the async task.

Signed-off-by: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>

init/do_mounts.c

@@ -284,8 +284,18 @@ dev_t name_to_dev_t(const char *name)
 	if (strcmp(name, "/dev/ram") == 0)
 		return Root_RAM0;
 #ifdef CONFIG_BLOCK
-	if (strncmp(name, "PARTUUID=", 9) == 0)
-		return devt_from_partuuid(name + 9);
+	if (strncmp(name, "PARTUUID=", 9) == 0) {
+		dev_t res;
+		int  needtowait = 40<<1;
+		res = devt_from_partuuid(name + 9);
+		while (!res && needtowait) {
+			/* waiting 0.5 sec */
+			msleep(500);
+			res = devt_from_partuuid(name + 9);
+			needtowait--;
+		}
+		return res;
+	}
 	if (strncmp(name, "PARTLABEL=", 10) == 0)
 		return devt_from_partlabel(name + 10);
 	if (strncmp(name, "/dev/", 5) == 0)
@@ -613,7 +623,9 @@ void __init prepare_namespace(void)
 	 * For example, it is not atypical to wait 5 seconds here
 	 * for the touchpad of a laptop to initialize.
 	 */
+	async_synchronize_full();
 	wait_for_device_probe();
+	async_synchronize_full();
 
 	md_run_setup();