xfrm: Indicate xfrm_state offload errors

Current code silently ignores driver errors when configuring
IPSec offload xfrm_state, and falls back to host-based crypto.

Fail the xfrm_state creation if the driver has an error, because
the NIC offloading was explicitly requested by the user program.

This will communicate back to the user that there was an error.

Fixes: d77e38e6 ("xfrm: Add an IPsec hardware offloading API")
Signed-off-by: Ilan Tayari <ilant@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/xfrm/xfrm_user.c

@@ -595,9 +595,12 @@ static struct xfrm_state *xfrm_state_construct(struct net *net,
 			goto error;
 	}
 
-	if (attrs[XFRMA_OFFLOAD_DEV] &&
-	    xfrm_dev_state_add(net, x, nla_data(attrs[XFRMA_OFFLOAD_DEV])))
+	if (attrs[XFRMA_OFFLOAD_DEV]) {
+		err = xfrm_dev_state_add(net, x,
+					 nla_data(attrs[XFRMA_OFFLOAD_DEV]));
+		if (err)
 			goto error;
+	}
 
 	if ((err = xfrm_alloc_replay_state_esn(&x->replay_esn, &x->preplay_esn,
 					       attrs[XFRMA_REPLAY_ESN_VAL])))