From: Johannes Berg <johannes.berg@xxxxxxxxx>
Seems like the extack cookie hasn't found any users outside
of wireless, which always uses nl_set_extack_cookie_u64().
Thus, allocating 20 bytes for it is pointless, reduce that
to 8 bytes, and add a BUILD_BUG_ON() to ensure it's enough
(obviously it is, for a u64, but in case it changes again.)
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
include/linux/netlink.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index c3ae84a77e16..882e9c1b6c1d 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -63,7 +63,7 @@ netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg)
}
/* this can be increased when necessary - don't expose to userland */
-#define NETLINK_MAX_COOKIE_LEN 20
+#define NETLINK_MAX_COOKIE_LEN 8
#define NETLINK_MAX_FMTMSG_LEN 80
/**
@@ -212,6 +212,7 @@ static inline void nl_set_extack_cookie_u64(struct netlink_ext_ack *extack,
{
if (!extack)
return;
+ BUILD_BUG_ON(sizeof(extack->cookie) < sizeof(cookie));
memcpy(extack->cookie, &cookie, sizeof(cookie));
extack->cookie_len = sizeof(cookie);
}
--
2.49.0
