On 15/02/16 16:02, Jiri Benc wrote:
On Mon, 15 Feb 2016 15:42:01 +0000, Robert Shearman wrote:+static const char *lwtunnel_encap_str(enum lwtunnel_encap_types encap_type) +{ + switch (encap_type) { + case LWTUNNEL_ENCAP_MPLS: + return "LWTUNNEL_ENCAP_MPLS"; + case LWTUNNEL_ENCAP_IP: + return "LWTUNNEL_ENCAP_IP"; + case LWTUNNEL_ENCAP_ILA: + return "LWTUNNEL_ENCAP_ILA"; + case LWTUNNEL_ENCAP_IP6: + return "LWTUNNEL_ENCAP_IP6"; + case LWTUNNEL_ENCAP_NONE: + case __LWTUNNEL_ENCAP_MAX: + /* should not have got here */ + break; + } + WARN_ON(1); + return "LWTUNNEL_ENCAP_NONE"; +} + +#endif /* CONFIG_MODULES */ + struct lwtunnel_state *lwtunnel_state_alloc(int encap_len) { struct lwtunnel_state *lws; @@ -85,6 +109,14 @@ int lwtunnel_build_state(struct net_device *dev, u16 encap_type, ret = -EOPNOTSUPP; rcu_read_lock(); ops = rcu_dereference(lwtun_encaps[encap_type]); +#ifdef CONFIG_MODULES + if (!ops) { + rcu_read_unlock(); + request_module("rtnl-lwt-%s", lwtunnel_encap_str(encap_type));Why the repeating of "lwt"/"LWTUNNEL" and the unnecessary "ENCAP"? Wouldn't be lwtunnel_encap_str returning just "MPLS" or "ILA" enough? I don't have any strong preference here, it just looks weird to me. Maybe there's a reason.
Yeah, it's the C preprocessor. MODULE_ALIAS_RTNL_LWT includes the string for the encap type in the module alias, and since the LWT encap types are defined as enums this is symbolic name. I can't see any way of getting the preprocessor to convert MODULE_ALIAS_RTNL_LWT(LWTUNNEL_ENCAP_MPLS) into "rtnl-lwt-MPLS", but I'm open to suggestions.
I could just drop the "lwt-" bit of the alias string given that it's included in the name of the enum values.
Also, this doesn't affect IP lwtunnels, i.e. LWTUNNEL_ENCAP_IP and LWTUNNEL_ENCAP_IP6. Should we just return NULL from lwtunnel_encap_str in such cases (plus unknown encap_type) and WARN on the NULL here?
True, but I figured that it was cleaner for the lwtunnel infra to not assume whether how those modules are implemented. If you disagree, then I can change to doing as you suggest.
Thanks, Rob
