net: mvneta: some small improvements

patch1 removes the NETIF_F_GRO check ourself, because the net subsystem will handle it for us.

patch2 enables NETIF_F_RXCSUM by default, since the driver and HW supports the feature.

patch3 is a small optimization, to reduce smp_processor_id() calling in mvneta_tx_done_gbe.

since v1:
- based on net-next tree
- remove the fix patches, since they should be based on net branch.
- Add Gregory's Reviewed-by tag

Jisheng Zhang (3):
net: mvneta: Don't check NETIF_F_GRO ourself
net: mvneta: enable NETIF_F_RXCSUM by default
net: mvneta: reduce smp_processor_id() calling in mvneta_tx_done_gbe

 drivers/net/ethernet/marvell/mvneta.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

2.18.0

napi_gro_receive() checks NETIF_F_GRO bit as well, if the bit is not set, we will go through GRO_NORMAL in napi_skb_finish(), so fall back to netif_receive_skb_internal(), so we don't need to check NETIF_F_GRO ourself.

---
 drivers/net/ethernet/marvell/mvneta.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

index bc80a678abc3..814aee92a1d3 100644
@@ -2065,10 +2065,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
 		/* Linux processing */
 		rxq->skb->protocol = eth_type_trans(rxq->skb, dev);
 
-		if (dev->features & NETIF_F_GRO)
-			napi_gro_receive(napi, rxq->skb);
-		else
-			netif_receive_skb(rxq->skb);
+		napi_gro_receive(napi, rxq->skb);
 
 		/* clean uncomplete skb pointer in queue */
 		rxq->skb = NULL;

2.18.0

The code and HW supports NETIF_F_RXCSUM, so let's enable it by default.

---
 drivers/net/ethernet/marvell/mvneta.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

index 814aee92a1d3..bcd20ebb2ebd 100644
@@ -4595,7 +4595,8 @@ static int mvneta_probe(struct platform_device *pdev)
 		}
 	}
 
-	dev->features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM | NETIF_F_TSO;
+	dev->features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
+			NETIF_F_TSO | NETIF_F_RXCSUM;
 	dev->hw_features |= dev->features;
 	dev->vlan_features |= dev->features;
 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;

2.18.0

Hi Jisheng

I ran some quick tests on a 370RD devel board, which uses a Marvell switch connected to mvneta. I did no see any obvious regressions.

Andrew

In the loop of mvneta_tx_done_gbe(), we call the smp_processor_id() each time, move the call out of the loop to optimize the code a bit.

Before the patch, the loop looks like(under arm64):

        ldr     x1, [x29,#120]
        ...
        ldr     w24, [x1,#36]
        ...
        bl      0 <_raw_spin_lock>
        str     w24, [x27,#132]
        ...

After the patch, the loop looks like(under arm64):

        ...
        bl      0 <_raw_spin_lock>
        str     w23, [x28,#132]
        ...

where w23 is loaded so be ready before the loop.

which is in non-preemptible context, so it's safe to call the smp_processor_id() function once.

---
 drivers/net/ethernet/marvell/mvneta.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

index bcd20ebb2ebd..fe3edb3c2bf4 100644
@@ -2507,12 +2507,13 @@ static void mvneta_tx_done_gbe(struct mvneta_port *pp, u32 cause_tx_done)
 {
 	struct mvneta_tx_queue *txq;
 	struct netdev_queue *nq;
+	int cpu = smp_processor_id();
 
 	while (cause_tx_done) {
 		txq = mvneta_tx_done_policy(pp, cause_tx_done);
 
 		nq = netdev_get_tx_queue(pp->dev, txq->id);
-		__netif_tx_lock(nq, smp_processor_id());
+		__netif_tx_lock(nq, cpu);
 
 		if (txq->count)
 			mvneta_txq_done(pp, txq);

2.18.0

From: Jisheng Zhang <[email protected]>
Date: Fri, 31 Aug 2018 16:08:10 +0800

Series applied, thanks.