netfilter: nftables: comment indirect serialization of commit_mutex w…

…ith rtnl_mutex Add an explicit comment in the code to describe the indirect serialization of the holders of the commit_mutex with the rtnl_mutex. Commit 90d2723 ("netfilter: nf_tables: do not hold reference on netdevice from preparation phase") already describes this, but a comment in this case is better for reference. Reported-by: Vladimir Oltean <[email protected]> Reviewed-by: Vladimir Oltean <[email protected]> Signed-off-by: Pablo Neira Ayuso <[email protected]>
walac · Dec 8, 2020 · 42f1c27 · 42f1c27
1 parent 917d80d
commit 42f1c27
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
@@ -1723,6 +1723,10 @@ static struct nft_hook *nft_netdev_hook_alloc(struct net *net,
 	}
 
 	nla_strlcpy(ifname, attr, IFNAMSIZ);
+	/* nf_tables_netdev_event() is called under rtnl_mutex, this is
+	 * indirectly serializing all the other holders of the commit_mutex with
+	 * the rtnl_mutex.
+	 */
 	dev = __dev_get_by_name(net, ifname);
 	if (!dev) {
 		err = -ENOENT;