[PATCH net-next-2.6 v8 18/20] CAN : Optimize "if" condition in rx/tx processing

[PATCH net-next-2.6 v8 18/20] CAN : Optimize "if" condition in rx/tx processing

[Tomoya MORINAGA]

For reduce "if" condition, easy to read/understand the code,
optimize "if" condition in rx/tx processing.

Signed-off-by: Tomoya MORINAGA <tomoya-linux-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>
---
 drivers/net/can/pch_can.c |   26 ++++++++++----------------
 1 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/drivers/net/can/pch_can.c b/drivers/net/can/pch_can.c
index 8efbe35..dcd8f00 100644
--- a/drivers/net/can/pch_can.c
+++ b/drivers/net/can/pch_can.c
@@ -746,19 +746,16 @@ static int pch_can_poll(struct napi_struct *napi, int quota)
 
 	if (int_stat == PCH_STATUS_INT) {
 		reg_stat = ioread32(&priv->regs->stat);
-		if (reg_stat & (PCH_BUS_OFF | PCH_LEC_ALL)) {
-			if (reg_stat & PCH_BUS_OFF ||
-			   (reg_stat & PCH_LEC_ALL) != PCH_LEC_ALL) {
-				pch_can_error(ndev, reg_stat);
-				quota--;
-			}
-		}
 
-		if (reg_stat & PCH_TX_OK)
-			pch_can_bit_clear(&priv->regs->stat, PCH_TX_OK);
+		if ((reg_stat & (PCH_BUS_OFF | PCH_LEC_ALL)) &&
+		   ((reg_stat & PCH_LEC_ALL) != PCH_LEC_ALL)) {
+			pch_can_error(ndev, reg_stat);
+			quota--;
+		}
 
-		if (reg_stat & PCH_RX_OK)
-			pch_can_bit_clear(&priv->regs->stat, PCH_RX_OK);
+		if (reg_stat & (PCH_TX_OK | PCH_RX_OK))
+			pch_can_bit_clear(&priv->regs->stat,
+					  reg_stat & (PCH_TX_OK | PCH_RX_OK));
 
 		int_stat = pch_can_int_pending(priv);
 	}
@@ -900,14 +897,13 @@ static netdev_tx_t pch_xmit(struct sk_buff *skb, struct net_device *ndev)
 	if (can_dropped_invalid_skb(ndev, skb))
 		return NETDEV_TX_OK;
 
+	tx_obj_no = priv->tx_obj;
 	if (priv->tx_obj == PCH_TX_OBJ_END) {
 		if (ioread32(&priv->regs->treq2) & PCH_TREQ2_TX_MASK)
 			netif_stop_queue(ndev);
 
-		tx_obj_no = priv->tx_obj;
 		priv->tx_obj = PCH_TX_OBJ_START;
 	} else {
-		tx_obj_no = priv->tx_obj;
 		priv->tx_obj++;
 	}
 
@@ -926,9 +922,7 @@ static netdev_tx_t pch_xmit(struct sk_buff *skb, struct net_device *ndev)
 	id2 |= PCH_ID_MSGVAL;
 
 	/* If remote frame has to be transmitted.. */
-	if (cf->can_id & CAN_RTR_FLAG)
-		id2 &= ~PCH_ID2_DIR;
-	else
+	if (!(cf->can_id & CAN_RTR_FLAG))
 		id2 |= PCH_ID2_DIR;
 
 	iowrite32(id2, &priv->regs->ifregs[1].id2);
-- 
1.6.0.6

Re: [PATCH net-next-2.6 v8 18/20] CAN : Optimize "if" condition in rx/tx processing

[Marc Kleine-Budde]

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On 12/07/2010 12:11 PM, Tomoya MORINAGA wrote:
> For reduce "if" condition, easy to read/understand the code,
> optimize "if" condition in rx/tx processing.
> 
> Signed-off-by: Tomoya MORINAGA <tomoya-linux-ECg8zkTtlr0C6LszWs/t0g@public.gmane.org>
Acked-by: Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> ---
>  drivers/net/can/pch_can.c |   26 ++++++++++----------------
>  1 files changed, 10 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/net/can/pch_can.c b/drivers/net/can/pch_can.c
> index 8efbe35..dcd8f00 100644
> --- a/drivers/net/can/pch_can.c
> +++ b/drivers/net/can/pch_can.c
> @@ -746,19 +746,16 @@ static int pch_can_poll(struct napi_struct *napi, int quota)
>  
>  	if (int_stat == PCH_STATUS_INT) {
>  		reg_stat = ioread32(&priv->regs->stat);
> -		if (reg_stat & (PCH_BUS_OFF | PCH_LEC_ALL)) {
> -			if (reg_stat & PCH_BUS_OFF ||
> -			   (reg_stat & PCH_LEC_ALL) != PCH_LEC_ALL) {
> -				pch_can_error(ndev, reg_stat);
> -				quota--;
> -			}
> -		}
>  
> -		if (reg_stat & PCH_TX_OK)
> -			pch_can_bit_clear(&priv->regs->stat, PCH_TX_OK);
> +		if ((reg_stat & (PCH_BUS_OFF | PCH_LEC_ALL)) &&
> +		   ((reg_stat & PCH_LEC_ALL) != PCH_LEC_ALL)) {
> +			pch_can_error(ndev, reg_stat);
> +			quota--;
> +		}
>  
> -		if (reg_stat & PCH_RX_OK)
> -			pch_can_bit_clear(&priv->regs->stat, PCH_RX_OK);
> +		if (reg_stat & (PCH_TX_OK | PCH_RX_OK))
> +			pch_can_bit_clear(&priv->regs->stat,
> +					  reg_stat & (PCH_TX_OK | PCH_RX_OK));
>  
>  		int_stat = pch_can_int_pending(priv);
>  	}
> @@ -900,14 +897,13 @@ static netdev_tx_t pch_xmit(struct sk_buff *skb, struct net_device *ndev)
>  	if (can_dropped_invalid_skb(ndev, skb))
>  		return NETDEV_TX_OK;
>  
> +	tx_obj_no = priv->tx_obj;
>  	if (priv->tx_obj == PCH_TX_OBJ_END) {
>  		if (ioread32(&priv->regs->treq2) & PCH_TREQ2_TX_MASK)
>  			netif_stop_queue(ndev);
>  
> -		tx_obj_no = priv->tx_obj;
>  		priv->tx_obj = PCH_TX_OBJ_START;
>  	} else {
> -		tx_obj_no = priv->tx_obj;
>  		priv->tx_obj++;
>  	}
>  
> @@ -926,9 +922,7 @@ static netdev_tx_t pch_xmit(struct sk_buff *skb, struct net_device *ndev)
>  	id2 |= PCH_ID_MSGVAL;
>  
>  	/* If remote frame has to be transmitted.. */
> -	if (cf->can_id & CAN_RTR_FLAG)
> -		id2 &= ~PCH_ID2_DIR;
> -	else
> +	if (!(cf->can_id & CAN_RTR_FLAG))
>  		id2 |= PCH_ID2_DIR;
>  
>  	iowrite32(id2, &priv->regs->ifregs[1].id2);


-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
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