lguest: Reboot support

Reboot Implemented

(Prevent fd leak, fix style and fix documentation --RR)

Signed-off-by: Balaji Rao <balajirrao@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
index f10abc8..c1069bc 100644
--- a/drivers/lguest/core.c
+++ b/drivers/lguest/core.c
@@ -235,6 +235,8 @@
 		lguest_arch_handle_trap(lg);
 	}
 
+	if (lg->dead == ERR_PTR(-ERESTART))
+		return -ERESTART;
 	/* The Guest is dead => "No such file or directory" */
 	return -ENOENT;
 }
diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c
index b478aff..05fad6f 100644
--- a/drivers/lguest/hypercalls.c
+++ b/drivers/lguest/hypercalls.c
@@ -41,8 +41,8 @@
 		 * do that. */
 		kill_guest(lg, "already have lguest_data");
 		break;
-	case LHCALL_CRASH: {
-		/* Crash is such a trivial hypercall that we do it in four
+	case LHCALL_SHUTDOWN: {
+		/* Shutdown is such a trivial hypercall that we do it in four
 		 * lines right here. */
 		char msg[128];
 		/* If the lgread fails, it will call kill_guest() itself; the
@@ -50,6 +50,8 @@
 		__lgread(lg, msg, args->arg1, sizeof(msg));
 		msg[sizeof(msg)-1] = '\0';
 		kill_guest(lg, "CRASH: %s", msg);
+		if (args->arg2 == LGUEST_SHUTDOWN_RESTART)
+			lg->dead = ERR_PTR(-ERESTART);
 		break;
 	}
 	case LHCALL_FLUSH_TLB: