net/tls: fix socket wmem accounting on fallback with netem

netem runs skb_orphan_partial() which "disconnects" the skb
from normal TCP write memory accounting.  We should not adjust
sk->sk_wmem_alloc on the fallback path for such skbs.

Fixes: e8f6979 ("net/tls: Add generic NIC offload infrastructure")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tls/tls_device_fallback.c

@@ -209,6 +209,10 @@ static void complete_skb(struct sk_buff *nskb, struct sk_buff *skb, int headln)
 
 	update_chksum(nskb, headln);
 
+	/* sock_efree means skb must gone through skb_orphan_partial() */
+	if (nskb->destructor == sock_efree)
+		return;
+
 	delta = nskb->truesize - skb->truesize;
 	if (likely(delta < 0))
 		WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));