netdev - [PATCH net-next 3/6] hv_netvsc: replace divide with mask when computing padding

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Message-Id: <20171201190149.22683-4-sthemmin@microsoft.com>
Date:   Fri,  1 Dec 2017 11:01:46 -0800
From:   Stephen Hemminger <stephen@...workplumber.org>
To:     kys@...rosoft.com, haiyangz@...rosoft.com, sthemmin@...rosoft.com
Cc:     devel@...uxdriverproject.org, netdev@...r.kernel.org
Subject: [PATCH net-next 3/6] hv_netvsc: replace divide with mask when computing padding

Packet alignment is always a power of 2 therefore modulus can
be replaced with a faster and operation

Signed-off-by: Stephen Hemminger <sthemmin@...rosoft.com>
---
 drivers/net/hyperv/netvsc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index ee31faa67cad..4b931f017a25 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -712,11 +712,12 @@ static u32 netvsc_copy_to_send_buf(struct netvsc_device *net_device,
 	int i;
 	u32 msg_size = 0;
 	u32 padding = 0;
-	u32 remain = packet->total_data_buflen % net_device->pkt_align;
 	u32 page_count = packet->cp_partial ? packet->rmsg_pgcnt :
 		packet->page_buf_cnt;
+	u32 remain;
 
 	/* Add padding */
+	remain = packet->total_data_buflen & (net_device->pkt_align - 1);
 	if (skb->xmit_more && remain && !packet->cp_partial) {
 		padding = net_device->pkt_align - remain;
 		rndis_msg->msg_len += padding;
-- 
2.11.0