thunderbolt: Fix to check for kmemdup failure

Memory allocated via kmemdup might fail and return a NULL pointer.
This patch adds a check on the return value of kmemdup and passes the
error upstream.
Signed-off-by: NAditya Pakki <pakki001@umn.edu>
Reviewed-by: NMukesh Ojha <mojha@codeaurora.org>
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/switch.c

@@ -1294,13 +1294,14 @@ int tb_switch_configure(struct tb_switch *sw)
 	return tb_plug_events_active(sw, true);
 }
 
-static void tb_switch_set_uuid(struct tb_switch *sw)
+static int tb_switch_set_uuid(struct tb_switch *sw)
 {
 	u32 uuid[4];
-	int cap;
+	int cap, ret;
 
+	ret = 0;
 	if (sw->uuid)
-		return;
+		return ret;
 
 	/*
 	 * The newer controllers include fused UUID as part of link
@@ -1308,7 +1309,9 @@ static void tb_switch_set_uuid(struct tb_switch *sw)
 	 */
 	cap = tb_switch_find_vse_cap(sw, TB_VSE_CAP_LINK_CONTROLLER);
 	if (cap > 0) {
-		tb_sw_read(sw, uuid, TB_CFG_SWITCH, cap + 3, 4);
+		ret = tb_sw_read(sw, uuid, TB_CFG_SWITCH, cap + 3, 4);
+		if (ret)
+			return ret;
 	} else {
 		/*
 		 * ICM generates UUID based on UID and fills the upper
@@ -1323,6 +1326,9 @@ static void tb_switch_set_uuid(struct tb_switch *sw)
 	}
 
 	sw->uuid = kmemdup(uuid, sizeof(uuid), GFP_KERNEL);
+	if (!sw->uuid)
+		ret = -ENOMEM;
+	return ret;
 }
 
 static int tb_switch_add_dma_port(struct tb_switch *sw)
@@ -1372,7 +1378,9 @@ static int tb_switch_add_dma_port(struct tb_switch *sw)
 
 	if (status) {
 		tb_sw_info(sw, "switch flash authentication failed\n");
-		tb_switch_set_uuid(sw);
+		ret = tb_switch_set_uuid(sw);
+		if (ret)
+			return ret;
 		nvm_set_auth_status(sw, status);
 	}
 
@@ -1422,7 +1430,9 @@ int tb_switch_add(struct tb_switch *sw)
 		}
 		tb_sw_dbg(sw, "uid: %#llx\n", sw->uid);
 
-		tb_switch_set_uuid(sw);
+		ret = tb_switch_set_uuid(sw);
+		if (ret)
+			return ret;
 
 		for (i = 0; i <= sw->config.max_port_number; i++) {
 			if (sw->ports[i].disabled) {