Removing GENL_ID_GENERATE breaks userspace API

Removing GENL_ID_GENERATE breaks userspace API

[Marcel Holtmann]

Hi Johannes,

you have removed GENL_ID_GENERATE in 4.10, but that is actually breaking userspace API.

commit a07ea4d9941af5a0c6f0be2a71b51ac9c083c5e5
Author: Johannes Berg <johannes.berg@intel.com>
Date:   Mon Oct 24 14:40:02 2016 +0200

    genetlink: no longer support using static family IDs

diff --git a/include/uapi/linux/genetlink.h b/include/uapi/linux/genetlink.h
index 5512c90af7e3..d9b2db4a29c6 100644
--- a/include/uapi/linux/genetlink.h
+++ b/include/uapi/linux/genetlink.h
@@ -26,7 +26,6 @@ struct genlmsghdr {
 /*
  * List of reserved static generic netlink identifiers:
  */
-#define GENL_ID_GENERATE       0
 #define GENL_ID_CTRL           NLMSG_MIN_TYPE

Since the GENL_ID_GENERATE is in include/uapi/ I would have expected that you leave this in. For us, you just broke userspace API with this change.

Regards

Marcel

Re: Removing GENL_ID_GENERATE breaks userspace API

[Johannes Berg]

On Thu, 2017-03-02 at 17:50 +0100, Marcel Holtmann wrote:
> Hi Johannes,
> 
> you have removed GENL_ID_GENERATE in 4.10, but that is actually
> breaking userspace API.
> 
> commit a07ea4d9941af5a0c6f0be2a71b51ac9c083c5e5
> Author: Johannes Berg <johannes.berg@intel.com>
> Date:   Mon Oct 24 14:40:02 2016 +0200
> 
>     genetlink: no longer support using static family IDs
> 
> diff --git a/include/uapi/linux/genetlink.h
> b/include/uapi/linux/genetlink.h
> index 5512c90af7e3..d9b2db4a29c6 100644
> --- a/include/uapi/linux/genetlink.h
> +++ b/include/uapi/linux/genetlink.h
> @@ -26,7 +26,6 @@ struct genlmsghdr {
>  /*
>   * List of reserved static generic netlink identifiers:
>   */
> -#define GENL_ID_GENERATE       0
>  #define GENL_ID_CTRL           NLMSG_MIN_TYPE
> 
> Since the GENL_ID_GENERATE is in include/uapi/ I would have expected
> that you leave this in. For us, you just broke userspace API with
> this change.

Huh. It makes no sense to be using it nor ever did, but I guess we can
add it back with a comment saying that it's actually needed - send a
patch?

johannes