On 4/8/17 1:48 PM, Johannes Berg wrote: > diff --git a/include/linux/netlink.h b/include/linux/netlink.h > index da14ab61f363..47562e940e9c 100644 > --- a/include/linux/netlink.h > +++ b/include/linux/netlink.h > @@ -62,11 +62,41 @@ netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg) > return __netlink_kernel_create(net, unit, THIS_MODULE, cfg); > } > > +/** > + * struct netlink_ext_ack - netlink extended ACK report struct > + * @_msg: message string to report - don't access directly, use > + * %NL_SET_ERR_MSG > + * @bad_attr: attribute with error > + * @missing_attr: number of missing attr (or 0) > + * @cookie: cookie data to return to userspace (for success) > + * @cookie_len: actual cookie data length > + */ > +struct netlink_ext_ack { > + const char *_msg; > + const struct nlattr *bad_attr; > + u16 missing_attr; > + u8 cookie[NETLINK_MAX_COOKIE_LEN]; > + u8 cookie_len; > +}; > + I think v3 is in your future ... /home/dsa/kernel-4.git/include/linux/netlink.h:78:12: error: ‘NETLINK_MAX_COOKIE_LEN’ undeclared here (not in a function) u8 cookie[NETLINK_MAX_COOKIE_LEN]; ^ it's defined in patch 3; needed in patch 1