netfilter: ipset: kernel: uapi: fix MARKMASK attr ABI breakage

commit 2dfb973c0dcc6d2211 (add markmask for hash:ip,mark data type)
inserted IPSET_ATTR_MARKMASK in-between other enum values, i.e.
changing values of all further attributes.  This causes 'ipset list'
segfault on existing kernels since ipset no longer finds
IPSET_ATTR_MEMSIZE (it has a different value on kernel side).

Jozsef points out it should be moved below IPSET_ATTR_MARK which
works since there is some extra reserved space after that value.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>

include/uapi/linux/netfilter/ipset/ip_set.h

@@ -83,13 +83,13 @@ enum {
 	IPSET_ATTR_CADT_FLAGS,	/* 8 */
 	IPSET_ATTR_CADT_LINENO = IPSET_ATTR_LINENO,	/* 9 */
 	IPSET_ATTR_MARK,	/* 10 */
+	IPSET_ATTR_MARKMASK,	/* 11 */
 	/* Reserve empty slots */
 	IPSET_ATTR_CADT_MAX = 16,
 	/* Create-only specific attributes */
 	IPSET_ATTR_GC,
 	IPSET_ATTR_HASHSIZE,
 	IPSET_ATTR_MAXELEM,
-	IPSET_ATTR_MARKMASK,
 	IPSET_ATTR_NETMASK,
 	IPSET_ATTR_PROBES,
 	IPSET_ATTR_RESIZE,
@@ -139,7 +139,6 @@ enum ipset_errno {
 	IPSET_ERR_EXIST,
 	IPSET_ERR_INVALID_CIDR,
 	IPSET_ERR_INVALID_NETMASK,
-	IPSET_ERR_INVALID_MARKMASK,
 	IPSET_ERR_INVALID_FAMILY,
 	IPSET_ERR_TIMEOUT,
 	IPSET_ERR_REFERENCED,
@@ -147,6 +146,7 @@ enum ipset_errno {
 	IPSET_ERR_IPADDR_IPV6,
 	IPSET_ERR_COUNTER,
 	IPSET_ERR_COMMENT,
+	IPSET_ERR_INVALID_MARKMASK,
 
 	/* Type specific error codes */
 	IPSET_ERR_TYPE_SPECIFIC = 4352,