[netdev/net][ppc][bisected 8550ff8] build fails net/core/dev.c:6020:19: error: dereferencing pointer

Greetings

netdev's net branch fails to build on my PowerPC box with error

net/core/dev.c: In function 'gro_list_prepare':
net/core/dev.c:6015:51: error: 'TC_SKB_EXT' undeclared (first use in this function); did you mean 'TC_U32_EAT'?
     struct tc_skb_ext *skb_ext = skb_ext_find(skb, TC_SKB_EXT);
                                                    ^~~~~~~~~~
                                                    TC_U32_EAT
net/core/dev.c:6015:51: note: each undeclared identifier is reported only once for each function it appears in
net/core/dev.c:6020:19: error: dereferencing pointer to incomplete type 'struct tc_skb_ext'
      diffs |= p_ext->chain ^ skb_ext->chain;
                    ^~
make[2]: *** [scripts/Makefile.build:273: net/core/dev.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [scripts/Makefile.build:516: net/core] Error 2
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:1847: net] Error 2
make: *** Waiting for unfinished jobs...

Which was included due to below commit

commit 8550ff8d8c75416e984d9c4b082845e57e560984
Author: Paul Blakey <paulb@nvidia.com  <mailto:paulb@nvidia.com>>
Date:   Mon Jul 5 13:54:51 2021 +0300

     skbuff: Release nfct refcount on napi stolen or re-used skbs
     
     When multiple SKBs are merged to a new skb under napi GRO,
     or SKB is re-used by napi, if nfct was set for them in the
     driver, it will not be released while freeing their stolen
     head state or on re-use.
     
     Release nfct on napi's stolen or re-used SKBs, and
     in gro_list_prepare, check conntrack metadata diff.
     
     Fixes: 5c6b94604744 ("net/mlx5e: CT: Handle misses after executing CT action")
     Reviewed-by: Roi Dayan <roid@nvidia.com  <mailto:roid@nvidia.com>>
     Signed-off-by: Paul Blakey <paulb@nvidia.com  <mailto:paulb@nvidia.com>>
     Signed-off-by: David S. Miller <davem@davemloft.net  <mailto:davem@davemloft.net>>

diff --git a/net/core/dev.c b/net/core/dev.c
index c253c2aafe97..177a5aec0b6b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c

@@ -6008,6 +6008,18 @@ static void gro_list_prepare(const struct list_head *head,
                         diffs = memcmp(skb_mac_header(p),
                                        skb_mac_header(skb),
                                        maclen);
+
+               diffs |= skb_get_nfct(p) ^ skb_get_nfct(skb);
+
+               if (!diffs) {
+                       struct tc_skb_ext *skb_ext = skb_ext_find(skb, TC_SKB_EXT);
+                       struct tc_skb_ext *p_ext = skb_ext_find(p, TC_SKB_EXT);
+
+                       diffs |= (!!p_ext) ^ (!!skb_ext);
+                       if (!diffs && unlikely(skb_ext))
+                               diffs |= p_ext->chain ^ skb_ext->chain;
+               }
+
                 NAPI_GRO_CB(p)->same_flow = !diffs;
         }
  }

kernel config is attached

@paul, could you please have a look into this ?

-- 
Regard's

Abdul Haleem
IBM Linux Technology Center