mptcp: allow changing the 'backup' bit when no sockets are open

current Linux refuses to change the 'backup' bit of MPTCP endpoints, i.e.
using MPTCP_PM_CMD_SET_FLAGS, unless it finds (at least) one subflow that
matches the endpoint address. There is no reason for that, so we can just
ignore the return value of mptcp_nl_addr_backup(). In this way, endpoints
can reconfigure their 'backup' flag even if no MPTCP sockets are open (or
more generally, in case the MP_PRIO message is not sent out).

Fixes: 0f9f696a502e ("mptcp: add set_flags command in PM netlink")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index c4f9a5ce3815307a6b54d5ac318d3eac98927d00..050eea231528bc762226bbd86d43447011428921 100644 (file)
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -1718,9 +1718,7 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
 
        list_for_each_entry(entry, &pernet->local_addr_list, list) {
                if (addresses_equal(&entry->addr, &addr.addr, true)) {
-                       ret = mptcp_nl_addr_backup(net, &entry->addr, bkup);
-                       if (ret)
-                               return ret;
+                       mptcp_nl_addr_backup(net, &entry->addr, bkup);
 
                        if (bkup)
                                entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;