ipsec: one thread index per-SA

Type: improvement

AN SA is uni-drectional therefore it can be used only for encrypt or
decrypt, not both. So it only needs one thread ID. free up some space on
the 1st cacheline.

Signed-off-by: Neale Ranns <neale@graphiant.com>
Change-Id: I21cb7cff70a763cbe2bffead860b574bc80b3136
diff --git a/src/vnet/ipsec/ah_decrypt.c b/src/vnet/ipsec/ah_decrypt.c
index 682f6cc..03a9dc8 100644
--- a/src/vnet/ipsec/ah_decrypt.c
+++ b/src/vnet/ipsec/ah_decrypt.c
@@ -176,16 +176,16 @@
 					  thread_index, current_sa_index);
 	}
 
-      if (PREDICT_FALSE (~0 == sa0->decrypt_thread_index))
+      if (PREDICT_FALSE (~0 == sa0->thread_index))
 	{
 	  /* this is the first packet to use this SA, claim the SA
 	   * for this thread. this could happen simultaneously on
 	   * another thread */
-	  clib_atomic_cmp_and_swap (&sa0->decrypt_thread_index, ~0,
+	  clib_atomic_cmp_and_swap (&sa0->thread_index, ~0,
 				    ipsec_sa_assign_thread (thread_index));
 	}
 
-      if (PREDICT_TRUE (thread_index != sa0->decrypt_thread_index))
+      if (PREDICT_TRUE (thread_index != sa0->thread_index))
 	{
 	  next[0] = AH_DECRYPT_NEXT_HANDOFF;
 	  goto next;