From e39579a9d0272ef22f42006b0767193b57a1dc2f Mon Sep 17 00:00:00 2001
From: Mandeep Singh Baines <msb@chromium.org>
Date: Fri, 4 Mar 2011 15:58:57 -0800
Subject: [PATCH] update_kernel: fix to be not rely on kernel command-line

This script recently stopped working when we changed the kernel cmdline.

Fix to be more robust by using rootdev instead.

BUG=12780
TEST=Updated my kernel.

Change-Id: I033f670c5db821863441ea1546c382fce3436c01

Review URL: http://codereview.chromium.org/6628027
---
 update_kernel.sh | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/update_kernel.sh b/update_kernel.sh
index b5cb818b43..6d0e61ba48 100755
--- a/update_kernel.sh
+++ b/update_kernel.sh
@@ -62,8 +62,12 @@ function learn_device() {
 # Ask the target what the kernel partition is
 function learn_partition() {
   [ -n "${FLAGS_partition}" ] && return
-  remote_sh cat /proc/cmdline
-  if echo "${REMOTE_OUT}" | egrep -q "${FLAGS_device}3"; then
+  ! remote_sh rootdev
+  if [ "${REMOTE_OUT}" == "/dev/dm-0" ]; then
+    remote_sh ls /sys/block/dm-0/slaves
+    REMOTE_OUT="/dev/${REMOTE_OUT}"
+  fi
+  if [ "${REMOTE_OUT}" == "${FLAGS_device}3" ]; then
     FLAGS_partition="${FLAGS_device}2"
   else
     FLAGS_partition="${FLAGS_device}4"