kmsg_dump: Dump on crash_kexec as well

crash_kexec gets called before kmsg_dump(KMSG_DUMP_OOPS) if
panic_on_oops is set, so the kernel log buffer is not stored
for this case.

This patch adds a KMSG_DUMP_KEXEC dump type which gets called
when crash_kexec() is invoked. To avoid getting double dumps,
the old KMSG_DUMP_PANIC is moved below crash_kexec(). The
mtdoops driver is modified to handle KMSG_DUMP_KEXEC in the
same way as a panic.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/kernel/panic.c b/kernel/panic.c
index 5827f7b..c787333 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -75,7 +75,6 @@
 	dump_stack();
 #endif
 
-	kmsg_dump(KMSG_DUMP_PANIC);
 	/*
 	 * If we have crashed and we have a crash kernel loaded let it handle
 	 * everything else.
@@ -83,6 +82,8 @@
 	 */
 	crash_kexec(NULL);
 
+	kmsg_dump(KMSG_DUMP_PANIC);
+
 	/*
 	 * Note smp_send_stop is the usual smp shutdown function, which
 	 * unfortunately means it may not be hardened to work in a panic