ip_tunnel: convert __be16 tunnel flags to bitmaps

Historically, tunnel flags like TUNNEL_CSUM or TUNNEL_ERSPAN_OPT
have been defined as __be16. Now all of those 16 bits are occupied
and there's no more free space for new flags.
It can't be simply switched to a bigger container with no
adjustments to the values, since it's an explicit Endian storage,
and on LE systems (__be16)0x0001 equals to
(__be64)0x0001000000000000.
We could probably define new 64-bit flags depending on the
Endianness, i.e. (__be64)0x0001 on BE and (__be64)0x00010000... on
LE, but that would introduce an Endianness dependency and spawn a
ton of Sparse warnings. To mitigate them, all of those places which
were adjusted with this change would be touched anyway, so why not
define stuff properly if there's no choice.

Define IP_TUNNEL_*_BIT counterparts as a bit number instead of the
value already coded and a fistful of <16 <-> bitmap> converters and
helpers. The two flags which have a different bit position are
SIT_ISATAP_BIT and VTI_ISVTI_BIT, as they were defined not as
__cpu_to_be16(), but as (__force __be16), i.e. had different
positions on LE and BE. Now they both have strongly defined places.
Change all __be16 fields which were used to store those flags, to
IP_TUNNEL_DECLARE_FLAGS() -> DECLARE_BITMAP(__IP_TUNNEL_FLAG_NUM) ->
unsigned long[1] for now, and replace all TUNNEL_* occurrences to
their bitmap counterparts. Use the converters in the places which talk
to the userspace, hardware (NFP) or other hosts (GRE header). The rest
must explicitly use the new flags only. This must be done at once,
otherwise there will be too many conversions throughout the code in
the intermediate commits.
Finally, disable the old __be16 flags for use in the kernel code
(except for the two 'irregular' flags mentioned above), to prevent
any accidental (mis)use of them. For the userspace, nothing is
changed, only additions were made.

Most noticeable bloat-o-meter difference (.text):

vmlinux:	307/-1 (306)
gre.ko:		62/0 (62)
ip_gre.ko:	941/-217 (724)	[*]
ip_tunnel.ko:	390/-900 (-510)	[**]
ip_vti.ko:	138/0 (138)
ip6_gre.ko:	534/-18 (516)	[*]
ip6_tunnel.ko:	118/-10 (108)

[*] gre_flags_to_tnl_flags() grew, but still is inlined
[**] ip_tunnel_find() got uninlined, hence such decrease

The average code size increase in non-extreme case is 100-200 bytes
per module, mostly due to sizeof(long) > sizeof(__be16), as
%__IP_TUNNEL_FLAG_NUM is less than %BITS_PER_LONG and the compilers
are able to expand the majority of bitmap_*() calls here into direct
operations on scalars.

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 17 deletions

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 2f6739fe78af..163f94a5a58f 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -225,10 +225,11 @@ static void geneve_rx(struct geneve_dev *geneve, struct geneve_sock *gs,
 	void *oiph;
 
 	if (ip_tunnel_collect_metadata() || gs->collect_md) {
-		__be16 flags;
+		IP_TUNNEL_DECLARE_FLAGS(flags) = { };
 
-		flags = TUNNEL_KEY | (gnvh->oam ? TUNNEL_OAM : 0) |
-			(gnvh->critical ? TUNNEL_CRIT_OPT : 0);
+		__set_bit(IP_TUNNEL_KEY_BIT, flags);
+		__assign_bit(IP_TUNNEL_OAM_BIT, flags, gnvh->oam);
+		__assign_bit(IP_TUNNEL_CRIT_OPT_BIT, flags, gnvh->critical);
 
 		tun_dst = udp_tun_rx_dst(skb, geneve_get_sk_family(gs), flags,
 					 vni_to_tunnel_id(gnvh->vni),
@@ -238,9 +239,11 @@ static void geneve_rx(struct geneve_dev *geneve, struct geneve_sock *gs,
 			goto drop;
 		}
 		/* Update tunnel dst according to Geneve options. */
+		ip_tunnel_flags_zero(flags);
+		__set_bit(IP_TUNNEL_GENEVE_OPT_BIT, flags);
 		ip_tunnel_info_opts_set(&tun_dst->u.tun_info,
 					gnvh->options, gnvh->opt_len * 4,
-					TUNNEL_GENEVE_OPT);
+					flags);
 	} else {
 		/* Drop packets w/ critical options,
 		 * since we don't support any...
@@ -745,14 +748,15 @@ static void geneve_build_header(struct genevehdr *geneveh,
 {
 	geneveh->ver = GENEVE_VER;
 	geneveh->opt_len = info->options_len / 4;
-	geneveh->oam = !!(info->key.tun_flags & TUNNEL_OAM);
-	geneveh->critical = !!(info->key.tun_flags & TUNNEL_CRIT_OPT);
+	geneveh->oam = test_bit(IP_TUNNEL_OAM_BIT, info->key.tun_flags);
+	geneveh->critical = test_bit(IP_TUNNEL_CRIT_OPT_BIT,
+				     info->key.tun_flags);
 	geneveh->rsvd1 = 0;
 	tunnel_id_to_vni(info->key.tun_id, geneveh->vni);
 	geneveh->proto_type = inner_proto;
 	geneveh->rsvd2 = 0;
 
-	if (info->key.tun_flags & TUNNEL_GENEVE_OPT)
+	if (test_bit(IP_TUNNEL_GENEVE_OPT_BIT, info->key.tun_flags))
 		ip_tunnel_info_opts_get(geneveh->options, info);
 }
 
@@ -761,7 +765,7 @@ static int geneve_build_skb(struct dst_entry *dst, struct sk_buff *skb,
 			    bool xnet, int ip_hdr_len,
 			    bool inner_proto_inherit)
 {
-	bool udp_sum = !!(info->key.tun_flags & TUNNEL_CSUM);
+	bool udp_sum = test_bit(IP_TUNNEL_CSUM_BIT, info->key.tun_flags);
 	struct genevehdr *gnvh;
 	__be16 inner_proto;
 	int min_headroom;
@@ -878,7 +882,8 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	if (geneve->cfg.collect_md) {
 		ttl = key->ttl;
 
-		df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0;
+		df = test_bit(IP_TUNNEL_DONT_FRAGMENT_BIT, key->tun_flags) ?
+		     htons(IP_DF) : 0;
 	} else {
 		if (geneve->cfg.ttl_inherit)
 			ttl = ip_tunnel_get_ttl(ip_hdr(skb), skb);
@@ -910,7 +915,8 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	udp_tunnel_xmit_skb(rt, gs4->sock->sk, skb, saddr, info->key.u.ipv4.dst,
 			    tos, ttl, df, sport, geneve->cfg.info.key.tp_dst,
 			    !net_eq(geneve->net, dev_net(geneve->dev)),
-			    !(info->key.tun_flags & TUNNEL_CSUM));
+			    !test_bit(IP_TUNNEL_CSUM_BIT,
+				      info->key.tun_flags));
 	return 0;
 }
 
@@ -998,7 +1004,8 @@ static int geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	udp_tunnel6_xmit_skb(dst, gs6->sock->sk, skb, dev,
 			     &saddr, &key->u.ipv6.dst, prio, ttl,
 			     info->key.label, sport, geneve->cfg.info.key.tp_dst,
-			     !(info->key.tun_flags & TUNNEL_CSUM));
+			     !test_bit(IP_TUNNEL_CSUM_BIT,
+				       info->key.tun_flags));
 	return 0;
 }
 #endif
@@ -1297,7 +1304,8 @@ static struct geneve_dev *geneve_find_dev(struct geneve_net *gn,
 
 static bool is_tnl_info_zero(const struct ip_tunnel_info *info)
 {
-	return !(info->key.tun_id || info->key.tun_flags || info->key.tos ||
+	return !(info->key.tun_id || info->key.tos ||
+		 !ip_tunnel_flags_empty(info->key.tun_flags) ||
 		 info->key.ttl || info->key.label || info->key.tp_src ||
 		 memchr_inv(&info->key.u, 0, sizeof(info->key.u)));
 }
@@ -1435,7 +1443,7 @@ static int geneve_nl2info(struct nlattr *tb[], struct nlattr *data[],
 					    "Remote IPv6 address cannot be Multicast");
 			return -EINVAL;
 		}
-		info->key.tun_flags |= TUNNEL_CSUM;
+		__set_bit(IP_TUNNEL_CSUM_BIT, info->key.tun_flags);
 		cfg->use_udp6_rx_checksums = true;
 #else
 		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_REMOTE6],
@@ -1510,7 +1518,7 @@ static int geneve_nl2info(struct nlattr *tb[], struct nlattr *data[],
 			goto change_notsup;
 		}
 		if (nla_get_u8(data[IFLA_GENEVE_UDP_CSUM]))
-			info->key.tun_flags |= TUNNEL_CSUM;
+			__set_bit(IP_TUNNEL_CSUM_BIT, info->key.tun_flags);
 	}
 
 	if (data[IFLA_GENEVE_UDP_ZERO_CSUM6_TX]) {
@@ -1520,7 +1528,7 @@ static int geneve_nl2info(struct nlattr *tb[], struct nlattr *data[],
 			goto change_notsup;
 		}
 		if (nla_get_u8(data[IFLA_GENEVE_UDP_ZERO_CSUM6_TX]))
-			info->key.tun_flags &= ~TUNNEL_CSUM;
+			__clear_bit(IP_TUNNEL_CSUM_BIT, info->key.tun_flags);
 #else
 		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_GENEVE_UDP_ZERO_CSUM6_TX],
 				    "IPv6 support not enabled in the kernel");
@@ -1753,7 +1761,8 @@ static int geneve_fill_info(struct sk_buff *skb, const struct net_device *dev)
 				    info->key.u.ipv4.dst))
 			goto nla_put_failure;
 		if (nla_put_u8(skb, IFLA_GENEVE_UDP_CSUM,
-			       !!(info->key.tun_flags & TUNNEL_CSUM)))
+			       test_bit(IP_TUNNEL_CSUM_BIT,
+					info->key.tun_flags)))
 			goto nla_put_failure;
 
 #if IS_ENABLED(CONFIG_IPV6)
@@ -1762,7 +1771,8 @@ static int geneve_fill_info(struct sk_buff *skb, const struct net_device *dev)
 				     &info->key.u.ipv6.dst))
 			goto nla_put_failure;
 		if (nla_put_u8(skb, IFLA_GENEVE_UDP_ZERO_CSUM6_TX,
-			       !(info->key.tun_flags & TUNNEL_CSUM)))
+			       !test_bit(IP_TUNNEL_CSUM_BIT,
+					 info->key.tun_flags)))
 			goto nla_put_failure;
 #endif
 	}