fastboot: retry mounting the root fs if we can't find init

currently we wait until all device init is done before trying to mount
the root fs, and to consequently execute init.

In preparation for relaxing the first delay, this patch adds a retry
attempt in case /sbin/init is not found. Before retrying, the code
will wait for all device init to complete.

While this patch by itself doesn't gain boot time yet (it needs follow on
patches), the alternative already is to panic()...

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/init/main.c b/init/main.c
index 3575b842442b..73785a4b2735 100644
--- a/init/main.c
+++ b/init/main.c
@@ -853,6 +853,7 @@ static void run_init_process(char *init_filename)
  */
 static int noinline init_post(void)
 {
+	int retry_count = 1;
 	free_initmem();
 	unlock_kernel();
 	mark_rodata_ro();
@@ -873,6 +874,7 @@ static int noinline init_post(void)
 				ramdisk_execute_command);
 	}
 
+retry:
 	/*
 	 * We try each of these until one succeeds.
 	 *
@@ -885,6 +887,23 @@ static int noinline init_post(void)
 					"defaults...\n", execute_command);
 	}
 	run_init_process("/sbin/init");
+
+	if (retry_count > 0) {
+		retry_count--;
+		/* 
+		 * We haven't found init yet... potentially because the device
+		 * is still being probed. We need to
+		 * - flush keventd and friends
+		 * - wait for the known devices to complete their probing
+		 * - try to mount the root fs again
+		 */
+		flush_scheduled_work();
+		while (driver_probe_done() != 0)
+			msleep(100);
+		prepare_namespace();
+		goto retry;
+	}
+	
 	run_init_process("/etc/init");
 	run_init_process("/bin/init");
 	run_init_process("/bin/sh");