Re: [PATCH net] genetlink: fix genlmsg_nlhdr()

[Johannes Berg <johannes@sipsolutions.net>]

On Wed, 2017-11-15 at 13:09 +0100, Michal Kubecek wrote:
> According to the description, first argument of genlmsg_nlhdr() points to
> what genlmsg_put() returns, i.e. beginning of user header. Therefore we
> should only subtract size of genetlink header and netlink message header,
> not user header.
> 
> This also means we don't need to pass the pointer to genetlink family and
> the same is true for genl_dump_check_consistent() which is the only caller
> of genlmsg_nlhdr(). (Note that at the moment, these functions are only
> used for families which do not have user header so that they are not
> affected.)
> 
> Fixes: 670dc2833d14 ("netlink: advertise incomplete dumps")
> Signed-off-by: Michal Kubecek <mkubecek@suse.cz>

Looks sensible, though I don't think it's really needed in net since it
really has no effect - as you note, family->hdrsize is 0 for all the
families calling this right now.

Reviewed-by: Johannes Berg <johannes@sipsolutions.net>

johannes