linux-kernel - [PATCH net-next-2.6 17/17 v3] can: EG20T PCH: Optimize "if" condition in rx/tx processing

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Message-ID: <4CED043A.3060907@dsn.okisemi.com>
Date:	Wed, 24 Nov 2010 21:25:30 +0900
From:	Tomoya MORINAGA <tomoya-linux@....okisemi.com>
To:	Wolfgang Grandegger <wg@...ndegger.com>,
	Wolfram Sang <w.sang@...gutronix.de>,
	Christian Pellegrin <chripell@...e.org>,
	Barry Song <21cnbao@...il.com>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	socketcan-core@...ts.berlios.de, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	"David S. Miller" <davem@...emloft.net>
CC:	qi.wang@...el.com, yong.y.wang@...el.com,
	andrew.chih.howe.khor@...el.com, joel.clark@...el.com,
	kok.howg.ewe@...el.com, margie.foster@...el.com
Subject: [PATCH net-next-2.6 17/17 v3] can: EG20T PCH: Optimize "if" condition
 in rx/tx processing

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

Signed-off-by: Tomoya MORINAGA <tomoya-linux@....okisemi.com>
---
 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 48f4a2e..0ecb0d5 100644
--- a/drivers/net/can/pch_can.c
+++ b/drivers/net/can/pch_can.c
@@ -758,19 +758,16 @@ 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);
 	}
@@ -917,14 +914,13 @@ 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++;
 	}

@@ -947,9 +943,7 @@ 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

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