netdev - [PATCH net-next 3/3] net: systemport: Simplify circular pointer arithmetic

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Date:   Thu, 23 Mar 2017 10:36:48 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, opendmb@...il.com,
        Florian Fainelli <f.fainelli@...il.com>
Subject: [PATCH net-next 3/3] net: systemport: Simplify circular pointer arithmetic

Similar to c298ede2fe21 ("net: bcmgenet: simplify circular pointer
arithmetic") we don't need to complex arthimetic since we always have a
ring size that is a power of 2.

Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
---
 drivers/net/ethernet/broadcom/bcmsysport.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
index c915bcfae0af..61e26c6b26ab 100644
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -682,11 +682,7 @@ static unsigned int bcm_sysport_desc_rx(struct bcm_sysport_priv *priv,
 		p_index = rdma_readl(priv, RDMA_CONS_INDEX);
 	p_index &= RDMA_PROD_INDEX_MASK;
 
-	if (p_index < priv->rx_c_index)
-		to_process = (RDMA_CONS_INDEX_MASK + 1) -
-			priv->rx_c_index + p_index;
-	else
-		to_process = p_index - priv->rx_c_index;
+	to_process = (p_index - priv->rx_c_index) & RDMA_CONS_INDEX_MASK;
 
 	netif_dbg(priv, rx_status, ndev,
 		  "p_index=%d rx_c_index=%d to_process=%d\n",
-- 
2.9.3