netdev - [PATCH net-next 10/15] netvsc: replace modulus with mask for alignment

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Message-Id: <20170503230117.20070-11-sthemmin@microsoft.com>
Date:   Wed,  3 May 2017 16:01:12 -0700
From:   Stephen Hemminger <stephen@...workplumber.org>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, Stephen Hemminger <sthemmin@...rosoft.com>
Subject: [PATCH net-next 10/15] netvsc: replace modulus with mask for alignment

Since packet alignment (pkt_align) is always a power of 2, it
is safe to replace expensive divide with shift.

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

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index d9bd1a2db4db..767ff20d659e 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -722,7 +722,7 @@ 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 remain = packet->total_data_buflen & (net_device->pkt_align - 1);
 	u32 page_count = packet->cp_partial ? packet->rmsg_pgcnt :
 		packet->page_buf_cnt;
 
-- 
2.11.0