sfc: Allow efx_channel_type::receive_skb() to reject a packet

Instead of having efx_ptp_rx() call netif_receive_skb() for an invalid
PTP packet, make it return false for rejected packets and have
efx_rx_deliver() pass them up.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

drivers/net/ethernet/sfc/net_driver.h

@@ -410,7 +410,7 @@ struct efx_channel_type {
 	void (*post_remove)(struct efx_channel *);
 	void (*get_name)(struct efx_channel *, char *buf, size_t len);
 	struct efx_channel *(*copy)(const struct efx_channel *);
-	void (*receive_skb)(struct efx_channel *, struct sk_buff *);
+	bool (*receive_skb)(struct efx_channel *, struct sk_buff *);
 	bool keep_eventq;
 };
 

drivers/net/ethernet/sfc/ptp.c

@@ -1006,7 +1006,7 @@ bool efx_ptp_is_ptp_tx(struct efx_nic *efx, struct sk_buff *skb)
  * the receive timestamp from the MC - this will probably occur after the
  * packet arrival because of the processing in the MC.
  */
-static void efx_ptp_rx(struct efx_channel *channel, struct sk_buff *skb)
+static bool efx_ptp_rx(struct efx_channel *channel, struct sk_buff *skb)
 {
 	struct efx_nic *efx = channel->efx;
 	struct efx_ptp_data *ptp = efx->ptp_data;
@@ -1019,18 +1019,15 @@ static void efx_ptp_rx(struct efx_channel *channel, struct sk_buff *skb)
 	/* Correct version? */
 	if (ptp->mode == MC_CMD_PTP_MODE_V1) {
 		if (skb->len < PTP_V1_MIN_LENGTH) {
-			netif_receive_skb(skb);
-			return;
+			return false;
 		}
 		version = ntohs(*(__be16 *)&skb->data[PTP_V1_VERSION_OFFSET]);
 		if (version != PTP_VERSION_V1) {
-			netif_receive_skb(skb);
-			return;
+			return false;
 		}
 	} else {
 		if (skb->len < PTP_V2_MIN_LENGTH) {
-			netif_receive_skb(skb);
-			return;
+			return false;
 		}
 		version = skb->data[PTP_V2_VERSION_OFFSET];
 
@@ -1041,8 +1038,7 @@ static void efx_ptp_rx(struct efx_channel *channel, struct sk_buff *skb)
 		BUILD_BUG_ON(PTP_V1_SEQUENCE_LENGTH != PTP_V2_SEQUENCE_LENGTH);
 
 		if ((version & PTP_VERSION_V2_MASK) != PTP_VERSION_V2) {
-			netif_receive_skb(skb);
-			return;
+			return false;
 		}
 	}
 
@@ -1073,6 +1069,8 @@ static void efx_ptp_rx(struct efx_channel *channel, struct sk_buff *skb)
 
 	skb_queue_tail(&ptp->rxq, skb);
 	queue_work(ptp->workwq, &ptp->work);
+
+	return true;
 }
 
 /* Transmit a PTP packet.  This has to be transmitted by the MC

drivers/net/ethernet/sfc/rx.c

@@ -575,12 +575,14 @@ static void efx_rx_deliver(struct efx_channel *channel,
 	/* Record the rx_queue */
 	skb_record_rx_queue(skb, channel->rx_queue.core_index);
 
-	/* Pass the packet up */
 	if (channel->type->receive_skb)
-		channel->type->receive_skb(channel, skb);
-	else
-		netif_receive_skb(skb);
+		if (channel->type->receive_skb(channel, skb))
+			goto handled;
+
+	/* Pass the packet up */
+	netif_receive_skb(skb);
 
+handled:
 	/* Update allocation strategy method */
 	channel->rx_alloc_level += RX_ALLOC_FACTOR_SKB;
 }