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

From: Ivan Khoronzhuk <[email-masked]>
Date: Fri, 27 Jul 2018 22:36:43 +0300

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.

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

-- 
Regards,
Ivan Khoronzhuk