[PATCH 5.3 01/25] netfilter: add missing IS_ENABLED(CONFIG_NF_TABLES) check to header-file.

[Greg Kroah-Hartman]

From: Jeremy Sowden <jeremy@xxxxxxxxxx>

commit 47e640af2e492cc28778dd6f894d50313f7fba75 upstream.

nf_tables.h defines an API comprising several inline functions and
macros that depend on the nft member of struct net.  However, this is
only defined is CONFIG_NF_TABLES is enabled.  Added preprocessor checks
to ensure that nf_tables.h will compile if CONFIG_NF_TABLES is disabled.

Signed-off-by: Jeremy Sowden <jeremy@xxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/netfilter-devel/20190920094925.aw7actk4tdnk3rke@salvia/T/
Fixes: 3c171f496ef5 ("netfilter: bridge: add connection tracking system")
Reported-by: Adam Borowski <kilobyte@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 include/net/netfilter/nf_tables.h |    4 ++++
 1 file changed, 4 insertions(+)

--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -1206,6 +1206,8 @@ void nft_trace_notify(struct nft_tracein
 #define MODULE_ALIAS_NFT_OBJ(type) \
 	MODULE_ALIAS("nft-obj-" __stringify(type))
 
+#if IS_ENABLED(CONFIG_NF_TABLES)
+
 /*
  * The gencursor defines two generations, the currently active and the
  * next one. Objects contain a bitmask of 2 bits specifying the generations
@@ -1279,6 +1281,8 @@ static inline void nft_set_elem_change_a
 	ext->genmask ^= nft_genmask_next(net);
 }
 
+#endif /* IS_ENABLED(CONFIG_NF_TABLES) */
+
 /*
  * We use a free bit in the genmask field to indicate the element
  * is busy, meaning it is currently being processed either by