sunrpc: Prevent resvport min/max inversion via sysfs and module parameter

The current min/max resvport settings are independently limited
by the entire range of allowed ports, so max_resvport can be
set to a port lower than min_resvport.

Prevent inversion of min/max values when set through sysfs and
module parameter by setting the limits dependent on each other.
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

net/sunrpc/xprtsock.c

@@ -3153,8 +3153,12 @@ static int param_set_uint_minmax(const char *val,
 
 static int param_set_portnr(const char *val, const struct kernel_param *kp)
 {
-	return param_set_uint_minmax(val, kp,
+	if (kp->arg == &xprt_min_resvport)
+		return param_set_uint_minmax(val, kp,
 			RPC_MIN_RESVPORT,
+			xprt_max_resvport);
+	return param_set_uint_minmax(val, kp,
+			xprt_min_resvport,
 			RPC_MAX_RESVPORT);
 }