Subject: Re: [PATCH] l2tp: generate correct module alias strings

From: Guillaume Nault <[email-masked]>
Date: Thu, 30 Mar 2023 12:23:02 +0200

On Thu, Mar 30, 2023 at 11:54:42AM +0200, Andrea Righi wrote:
> Commit 65b32f801bfb ("uapi: move IPPROTO_L2TP to in.h") moved the
> definition of IPPROTO_L2TP from a define to an enum, but since
> __stringify doesn't work properly with enums, we ended up breaking the
> modalias strings for the l2tp modules:
> 
>  $ modinfo l2tp_ip l2tp_ip6 | grep alias
>  alias:          net-pf-2-proto-IPPROTO_L2TP
>  alias:          net-pf-2-proto-2-type-IPPROTO_L2TP
>  alias:          net-pf-10-proto-IPPROTO_L2TP
>  alias:          net-pf-10-proto-2-type-IPPROTO_L2TP
> 
> Use the resolved number directly in MODULE_ALIAS_*() macros (as we
> already do with SOCK_DGRAM) to fix the alias strings:
> 
> $ modinfo l2tp_ip l2tp_ip6 | grep alias
> alias:          net-pf-2-proto-115
> alias:          net-pf-2-proto-115-type-2
> alias:          net-pf-10-proto-115
> alias:          net-pf-10-proto-115-type-2
> 
> Moreover, fix the ordering of the parameters passed to
> MODULE_ALIAS_NET_PF_PROTO_TYPE() by switching proto and type.

Thanks!

Just to be explicit to the maintainers, this patch is for the net tree
(next time, you can use [PATCH net] to make that clear).

> Fixes: 65b32f801bfb ("uapi: move IPPROTO_L2TP to in.h")
> Link: https://lore.kernel.org/lkml/ZCQt7hmodtUaBlCP@righiandr-XPS-13-7390
> Signed-off-by: Guillaume Nault <[email-masked]>
> Signed-off-by: Andrea Righi <[email-masked]>
> ---
>  net/l2tp/l2tp_ip.c  | 8 ++++----
>  net/l2tp/l2tp_ip6.c | 8 ++++----
>  2 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
> index 4db5a554bdbd..41a74fc84ca1 100644
> --- a/net/l2tp/l2tp_ip.c
> +++ b/net/l2tp/l2tp_ip.c
> @@ -677,8 +677,8 @@ MODULE_AUTHOR("James Chapman <[email-masked]>");
>  MODULE_DESCRIPTION("L2TP over IP");
>  MODULE_VERSION("1.0");
>  
> -/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
> - * enums
> +/* Use the values of SOCK_DGRAM (2) as type and IPPROTO_L2TP (115) as protocol,
> + * because __stringify doesn't like enums
>   */
> -MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
> -MODULE_ALIAS_NET_PF_PROTO(PF_INET, IPPROTO_L2TP);
> +MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 115, 2);
> +MODULE_ALIAS_NET_PF_PROTO(PF_INET, 115);
> diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c
> index 2478aa60145f..5137ea1861ce 100644
> --- a/net/l2tp/l2tp_ip6.c
> +++ b/net/l2tp/l2tp_ip6.c
> @@ -806,8 +806,8 @@ MODULE_AUTHOR("Chris Elston <[email-masked]>");
>  MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
>  MODULE_VERSION("1.0");
>  
> -/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
> - * enums
> +/* Use the values of SOCK_DGRAM (2) as type and IPPROTO_L2TP (115) as protocol,
> + * because __stringify doesn't like enums
>   */
> -MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
> -MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);
> +MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 115, 2);
> +MODULE_ALIAS_NET_PF_PROTO(PF_INET6, 115);
> -- 
> 2.39.2
>