Subject: Re: [PATCH net-next] net: ethernet: ti: cpsw: replace unnecessarily macroses on functions

From: Ivan Khoronzhuk <[email-masked]>
Date: Fri, 27 Jul 2018 22:52:56 +0300

On Fri, Jul 27, 2018 at 10:36:43PM +0300, Ivan Khoronzhuk wrote:
>On Fri, Jul 27, 2018 at 12:21:07PM -0700, Joe Perches wrote:
>>On Fri, 2018-07-27 at 22:13 +0300, Ivan Khoronzhuk wrote:
>>>Replace ugly macroses on functions.
>>
>>Careful, see below.
>>
>>>diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
>>[]
>>>@@ -565,40 +565,40 @@ static const struct cpsw_stats cpsw_gstrings_ch_stats[] = {
>>> 				(func)(slave++, ##arg);			\
>>> 	} while (0)
>>>
>>>-#define cpsw_dual_emac_src_port_detect(cpsw, status, ndev, skb)		\
>>>-	do {								\
>>>-		if (!cpsw->data.dual_emac)				\
>>>-			break;						\
>>>-		if (CPDMA_RX_SOURCE_PORT(status) == 1) {		\
>>>-			ndev = cpsw->slaves[0].ndev;			\
>>>-			skb->dev = ndev;				\
>>>-		} else if (CPDMA_RX_SOURCE_PORT(status) == 2) {		\
>>>-			ndev = cpsw->slaves[1].ndev;			\
>>>-			skb->dev = ndev;				\
>>>-		}							\
>>>-	} while (0)
>>>-#define cpsw_add_mcast(cpsw, priv, addr)				\
>>>-	do {								\
>>>-		if (cpsw->data.dual_emac) {				\
>>>-			struct cpsw_slave *slave = cpsw->slaves +	\
>>>-						priv->emac_port;	\
>>>-			int slave_port = cpsw_get_slave_port(		\
>>>-						slave->slave_num);	\
>>>-			cpsw_ale_add_mcast(cpsw->ale, addr,		\
>>>-				1 << slave_port | ALE_PORT_HOST,	\
>>>-				ALE_VLAN, slave->port_vlan, 0);		\
>>>-		} else {						\
>>>-			cpsw_ale_add_mcast(cpsw->ale, addr,		\
>>>-				ALE_ALL_PORTS,				\
>>>-				0, 0, 0);				\
>>>-		}							\
>>>-	} while (0)
>>>-
>>> static inline int cpsw_get_slave_port(u32 slave_num)
>>> {
>>> 	return slave_num + 1;
>>> }
>>>
>>>+static inline void cpsw_src_port_detect(struct cpsw_common *cpsw, int status,
>>>+					struct sk_buff *skb)
>>>+{
>>>+	if (!cpsw->data.dual_emac)
>>>+		return;
>>>+
>>>+	if (CPDMA_RX_SOURCE_PORT(status) == 1)
>>>+		skb->dev = cpsw->slaves[0].ndev;
>>>+	else if (CPDMA_RX_SOURCE_PORT(status) == 2)
>>>+		skb->dev = cpsw->slaves[1].ndev;
>>>+}
>>
>>perhaps better as a switch/case
>not better, it's shorter.
>
>>
>>>+
>>>+static void cpsw_add_mcast(struct cpsw_priv *priv, u8 *addr)
>>>+{
>>>+	struct cpsw_common *cpsw = priv->cpsw;
>>>+
>>>+	if (cpsw->data.dual_emac) {
>>>+		struct cpsw_slave *slave = cpsw->slaves + priv->emac_port;
>>>+		int slave_port = cpsw_get_slave_port(slave->slave_num);
>>>+
>>>+		cpsw_ale_add_mcast(cpsw->ale, addr,
>>>+				   1 << slave_port | ALE_PORT_HOST,
>>>+				   ALE_VLAN, slave->port_vlan, 0);
>>>+		return;
>>>+	}
>>>+
>>>+	cpsw_ale_add_mcast(cpsw->ale, addr, ALE_ALL_PORTS, 0, 0, 0);
>>>+}
>>>+
>>> static void cpsw_set_promiscious(struct net_device *ndev, bool enable)
>>> {
>>> 	struct cpsw_common *cpsw = ndev_to_cpsw(ndev);
>>>@@ -706,7 +706,7 @@ static void cpsw_ndo_set_rx_mode(struct net_device *ndev)
>>>
>>> 		/* program multicast address list into ALE register */
>>> 		netdev_for_each_mc_addr(ha, ndev) {
>>>-			cpsw_add_mcast(cpsw, priv, (u8 *)ha->addr);
>>>+			cpsw_add_mcast(priv, (u8 *)ha->addr);
>>> 		}
>>> 	}
>>> }
>>>@@ -801,7 +801,8 @@ static void cpsw_rx_handler(void *token, int len, int status)
>>> 	int			ret = 0;
>>> 	struct cpsw_common	*cpsw = ndev_to_cpsw(ndev);
>>>
>>>-	cpsw_dual_emac_src_port_detect(cpsw, status, ndev, skb);
>>>+	cpsw_src_port_detect(cpsw, status, skb);
>>>+	ndev = skb->dev;
>>
>>This is not the same code as the new function
>>is not guaranteed to succeed or set skb->dev.
>Guaranteed by above skb->dev is initialized already.
>The function reflects previous macro.
>
>Even more, seems that here is duplication of ndev=skb->dev;
>It should be removed at init ), even if it 100% is optimized by complier.
>So guaranteed a little more then needed ), will send v2 with removed
>ndev = skb->dev at init if no objection.

But no, not duplicates.
It's used to get cpsw. So everyting is fine.
Patch should go as is.

>
>>
>>> 	if (unlikely(status < 0) || unlikely(!netif_running(ndev))) {
>>> 		/* In dual emac mode check for all interfaces */
>
>-- 
>Regards,
>Ivan Khoronzhuk

-- 
Regards,
Ivan Khoronzhuk