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, 37 insertions, 24 deletions

diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index ebc5728aab4e..f224d9bcea5e 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -152,6 +152,13 @@ static void update_range(struct sw_flow_match *match,
 			       sizeof((match)->key->field));                \
 	} while (0)
 
+#define SW_FLOW_KEY_BITMAP_COPY(match, field, value_p, nbits, is_mask) ({     \
+	update_range(match, offsetof(struct sw_flow_key, field),	      \
+		     bitmap_size(nbits), is_mask);			      \
+	bitmap_copy(is_mask ? (match)->mask->key.field : (match)->key->field, \
+		    value_p, nbits);					      \
+})
+
 static bool match_validate(const struct sw_flow_match *match,
 			   u64 key_attrs, u64 mask_attrs, bool log)
 {
@@ -670,8 +677,8 @@ static int ip_tun_from_nlattr(const struct nlattr *attr,
 			      bool log)
 {
 	bool ttl = false, ipv4 = false, ipv6 = false;
+	IP_TUNNEL_DECLARE_FLAGS(tun_flags) = { };
 	bool info_bridge_mode = false;
-	__be16 tun_flags = 0;
 	int opts_type = 0;
 	struct nlattr *a;
 	int rem;
@@ -697,7 +704,7 @@ static int ip_tun_from_nlattr(const struct nlattr *attr,
 		case OVS_TUNNEL_KEY_ATTR_ID:
 			SW_FLOW_KEY_PUT(match, tun_key.tun_id,
 					nla_get_be64(a), is_mask);
-			tun_flags |= TUNNEL_KEY;
+			__set_bit(IP_TUNNEL_KEY_BIT, tun_flags);
 			break;
 		case OVS_TUNNEL_KEY_ATTR_IPV4_SRC:
 			SW_FLOW_KEY_PUT(match, tun_key.u.ipv4.src,
@@ -729,10 +736,10 @@ static int ip_tun_from_nlattr(const struct nlattr *attr,
 			ttl = true;
 			break;
 		case OVS_TUNNEL_KEY_ATTR_DONT_FRAGMENT:
-			tun_flags |= TUNNEL_DONT_FRAGMENT;
+			__set_bit(IP_TUNNEL_DONT_FRAGMENT_BIT, tun_flags);
 			break;
 		case OVS_TUNNEL_KEY_ATTR_CSUM:
-			tun_flags |= TUNNEL_CSUM;
+			__set_bit(IP_TUNNEL_CSUM_BIT, tun_flags);
 			break;
 		case OVS_TUNNEL_KEY_ATTR_TP_SRC:
 			SW_FLOW_KEY_PUT(match, tun_key.tp_src,
@@ -743,7 +750,7 @@ static int ip_tun_from_nlattr(const struct nlattr *attr,
 					nla_get_be16(a), is_mask);
 			break;
 		case OVS_TUNNEL_KEY_ATTR_OAM:
-			tun_flags |= TUNNEL_OAM;
+			__set_bit(IP_TUNNEL_OAM_BIT, tun_flags);
 			break;
 		case OVS_TUNNEL_KEY_ATTR_GENEVE_OPTS:
 			if (opts_type) {
@@ -755,7 +762,7 @@ static int ip_tun_from_nlattr(const struct nlattr *attr,
 			if (err)
 				return err;
 
-			tun_flags |= TUNNEL_GENEVE_OPT;
+			__set_bit(IP_TUNNEL_GENEVE_OPT_BIT, tun_flags);
 			opts_type = type;
 			break;
 		case OVS_TUNNEL_KEY_ATTR_VXLAN_OPTS:
@@ -768,7 +775,7 @@ static int ip_tun_from_nlattr(const struct nlattr *attr,
 			if (err)
 				return err;
 
-			tun_flags |= TUNNEL_VXLAN_OPT;
+			__set_bit(IP_TUNNEL_VXLAN_OPT_BIT, tun_flags);
 			opts_type = type;
 			break;
 		case OVS_TUNNEL_KEY_ATTR_PAD:
@@ -784,7 +791,7 @@ static int ip_tun_from_nlattr(const struct nlattr *attr,
 			if (err)
 				return err;
 
-			tun_flags |= TUNNEL_ERSPAN_OPT;
+			__set_bit(IP_TUNNEL_ERSPAN_OPT_BIT, tun_flags);
 			opts_type = type;
 			break;
 		case OVS_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE:
@@ -798,7 +805,8 @@ static int ip_tun_from_nlattr(const struct nlattr *attr,
 		}
 	}
 
-	SW_FLOW_KEY_PUT(match, tun_key.tun_flags, tun_flags, is_mask);
+	SW_FLOW_KEY_BITMAP_COPY(match, tun_key.tun_flags, tun_flags,
+				__IP_TUNNEL_FLAG_NUM, is_mask);
 	if (is_mask)
 		SW_FLOW_KEY_MEMSET_FIELD(match, tun_proto, 0xff, true);
 	else
@@ -823,13 +831,15 @@ static int ip_tun_from_nlattr(const struct nlattr *attr,
 		}
 		if (ipv4) {
 			if (info_bridge_mode) {
+				__clear_bit(IP_TUNNEL_KEY_BIT, tun_flags);
+
 				if (match->key->tun_key.u.ipv4.src ||
 				    match->key->tun_key.u.ipv4.dst ||
 				    match->key->tun_key.tp_src ||
 				    match->key->tun_key.tp_dst ||
 				    match->key->tun_key.ttl ||
 				    match->key->tun_key.tos ||
-				    tun_flags & ~TUNNEL_KEY) {
+				    !ip_tunnel_flags_empty(tun_flags)) {
 					OVS_NLERR(log, "IPv4 tun info is not correct");
 					return -EINVAL;
 				}
@@ -874,7 +884,7 @@ static int __ip_tun_to_nlattr(struct sk_buff *skb,
 			      const void *tun_opts, int swkey_tun_opts_len,
 			      unsigned short tun_proto, u8 mode)
 {
-	if (output->tun_flags & TUNNEL_KEY &&
+	if (test_bit(IP_TUNNEL_KEY_BIT, output->tun_flags) &&
 	    nla_put_be64(skb, OVS_TUNNEL_KEY_ATTR_ID, output->tun_id,
 			 OVS_TUNNEL_KEY_ATTR_PAD))
 		return -EMSGSIZE;
@@ -910,10 +920,10 @@ static int __ip_tun_to_nlattr(struct sk_buff *skb,
 		return -EMSGSIZE;
 	if (nla_put_u8(skb, OVS_TUNNEL_KEY_ATTR_TTL, output->ttl))
 		return -EMSGSIZE;
-	if ((output->tun_flags & TUNNEL_DONT_FRAGMENT) &&
+	if (test_bit(IP_TUNNEL_DONT_FRAGMENT_BIT, output->tun_flags) &&
 	    nla_put_flag(skb, OVS_TUNNEL_KEY_ATTR_DONT_FRAGMENT))
 		return -EMSGSIZE;
-	if ((output->tun_flags & TUNNEL_CSUM) &&
+	if (test_bit(IP_TUNNEL_CSUM_BIT, output->tun_flags) &&
 	    nla_put_flag(skb, OVS_TUNNEL_KEY_ATTR_CSUM))
 		return -EMSGSIZE;
 	if (output->tp_src &&
@@ -922,18 +932,20 @@ static int __ip_tun_to_nlattr(struct sk_buff *skb,
 	if (output->tp_dst &&
 	    nla_put_be16(skb, OVS_TUNNEL_KEY_ATTR_TP_DST, output->tp_dst))
 		return -EMSGSIZE;
-	if ((output->tun_flags & TUNNEL_OAM) &&
+	if (test_bit(IP_TUNNEL_OAM_BIT, output->tun_flags) &&
 	    nla_put_flag(skb, OVS_TUNNEL_KEY_ATTR_OAM))
 		return -EMSGSIZE;
 	if (swkey_tun_opts_len) {
-		if (output->tun_flags & TUNNEL_GENEVE_OPT &&
+		if (test_bit(IP_TUNNEL_GENEVE_OPT_BIT, output->tun_flags) &&
 		    nla_put(skb, OVS_TUNNEL_KEY_ATTR_GENEVE_OPTS,
 			    swkey_tun_opts_len, tun_opts))
 			return -EMSGSIZE;
-		else if (output->tun_flags & TUNNEL_VXLAN_OPT &&
+		else if (test_bit(IP_TUNNEL_VXLAN_OPT_BIT,
+				  output->tun_flags) &&
 			 vxlan_opt_to_nlattr(skb, tun_opts, swkey_tun_opts_len))
 			return -EMSGSIZE;
-		else if (output->tun_flags & TUNNEL_ERSPAN_OPT &&
+		else if (test_bit(IP_TUNNEL_ERSPAN_OPT_BIT,
+				  output->tun_flags) &&
 			 nla_put(skb, OVS_TUNNEL_KEY_ATTR_ERSPAN_OPTS,
 				 swkey_tun_opts_len, tun_opts))
 			return -EMSGSIZE;
@@ -2029,7 +2041,7 @@ static int __ovs_nla_put_key(const struct sw_flow_key *swkey,
 	if ((swkey->tun_proto || is_mask)) {
 		const void *opts = NULL;
 
-		if (output->tun_key.tun_flags & TUNNEL_OPTIONS_PRESENT)
+		if (ip_tunnel_is_options_present(output->tun_key.tun_flags))
 			opts = TUN_METADATA_OPTS(output, swkey->tun_opts_len);
 
 		if (ip_tun_to_nlattr(skb, &output->tun_key, opts,
@@ -2752,7 +2764,8 @@ static int validate_geneve_opts(struct sw_flow_key *key)
 		opts_len -= len;
 	}
 
-	key->tun_key.tun_flags |= crit_opt ? TUNNEL_CRIT_OPT : 0;
+	if (crit_opt)
+		__set_bit(IP_TUNNEL_CRIT_OPT_BIT, key->tun_key.tun_flags);
 
 	return 0;
 }
@@ -2760,6 +2773,7 @@ static int validate_geneve_opts(struct sw_flow_key *key)
 static int validate_and_copy_set_tun(const struct nlattr *attr,
 				     struct sw_flow_actions **sfa, bool log)
 {
+	IP_TUNNEL_DECLARE_FLAGS(dst_opt_type) = { };
 	struct sw_flow_match match;
 	struct sw_flow_key key;
 	struct metadata_dst *tun_dst;
@@ -2767,9 +2781,7 @@ static int validate_and_copy_set_tun(const struct nlattr *attr,
 	struct ovs_tunnel_info *ovs_tun;
 	struct nlattr *a;
 	int err = 0, start, opts_type;
-	__be16 dst_opt_type;
 
-	dst_opt_type = 0;
 	ovs_match_init(&match, &key, true, NULL);
 	opts_type = ip_tun_from_nlattr(nla_data(attr), &match, false, log);
 	if (opts_type < 0)
@@ -2781,13 +2793,14 @@ static int validate_and_copy_set_tun(const struct nlattr *attr,
 			err = validate_geneve_opts(&key);
 			if (err < 0)
 				return err;
-			dst_opt_type = TUNNEL_GENEVE_OPT;
+
+			__set_bit(IP_TUNNEL_GENEVE_OPT_BIT, dst_opt_type);
 			break;
 		case OVS_TUNNEL_KEY_ATTR_VXLAN_OPTS:
-			dst_opt_type = TUNNEL_VXLAN_OPT;
+			__set_bit(IP_TUNNEL_VXLAN_OPT_BIT, dst_opt_type);
 			break;
 		case OVS_TUNNEL_KEY_ATTR_ERSPAN_OPTS:
-			dst_opt_type = TUNNEL_ERSPAN_OPT;
+			__set_bit(IP_TUNNEL_ERSPAN_OPT_BIT, dst_opt_type);
 			break;
 		}
 	}