target/user: Make sure netlink would reach all network namespaces

The current code only allow netlink to reach the initial network namespace,
which caused trouble for any client running inside container.

This patch would make sure TCMU netlink would work for all network
namespaces.

Signed-off-by: Sheng Yang <sheng@yasker.org>
Acked-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_user.c

@@ -152,6 +152,7 @@ static struct genl_family tcmu_genl_family = {
 	.maxattr = TCMU_ATTR_MAX,
 	.mcgrps = tcmu_mcgrps,
 	.n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
+	.netnsok = true,
 };
 
 static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
@@ -840,7 +841,7 @@ static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int mino
 
 	genlmsg_end(skb, msg_header);
 
-	ret = genlmsg_multicast(&tcmu_genl_family, skb, 0,
+	ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0,
 				TCMU_MCGRP_CONFIG, GFP_KERNEL);
 
 	/* We don't care if no one is listening */