Commit a462903f authored by Johannes Berg's avatar Johannes Berg Committed by Jakub Kicinski
Browse files

net: netlink: reduce extack cookie size 



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: default avatarJohannes Berg <johannes.berg@intel.com>
Link: https://patch.msgid.link/20250516115927.38209-2-johannes@sipsolutions.net


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent a8ae8a0e

include/linux/netlink.h

+2 −1
Original line number Diff line number Diff line
@@ -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);

}