rhashtable: accept GFP flags in rhashtable_walk_init

In certain cases, the 802.11 mesh pathtable code wants to
iterate over all of the entries in the forwarding table from
the receive path, which is inside an RCU read-side critical
section.  Enable walks inside atomic sections by allowing
GFP_ATOMIC allocations for the walker state.

Change all existing callsites to pass in GFP_KERNEL.

Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Bob Copeland <me@bobcopeland.com>
[also adjust gfs2/glock.c and rhashtable tests]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/ipv6/ila/ila_xlat.c

@@ -501,7 +501,8 @@ static int ila_nl_dump_start(struct netlink_callback *cb)
 	struct ila_net *ilan = net_generic(net, ila_net_id);
 	struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args;
 
-	return rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter);
+	return rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter,
+				    GFP_KERNEL);
 }
 
 static int ila_nl_dump_done(struct netlink_callback *cb)