[PATCH] net: core: improve the tx_hash calculating

From: Tonghao Zhang <xiangxia.m.yue@gmail.com>
To: netdev@vger.kernel.org
Cc: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Subject: [PATCH] net: core: improve the tx_hash calculating
Date: Thu, 31 May 2018 03:14:01 -0700	[thread overview]
Message-ID: <1527761641-22034-1-git-send-email-xiangxia.m.yue@gmail.com> (raw)

Use the % instead of while, and it may simple code and improve
the calculating. The real_num_tx_queues has been checked when
allocating and setting it.

Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
---
 net/core/dev.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 1844d9b..edc5b75 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2617,15 +2617,13 @@ void netif_device_attach(struct net_device *dev)
  */
 static u16 skb_tx_hash(const struct net_device *dev, struct sk_buff *skb)
 {
-	u32 hash;
 	u16 qoffset = 0;
 	u16 qcount = dev->real_num_tx_queues;
 
 	if (skb_rx_queue_recorded(skb)) {
-		hash = skb_get_rx_queue(skb);
-		while (unlikely(hash >= qcount))
-			hash -= qcount;
-		return hash;
+		/* When setting the real_num_tx_queues, we make sure
+		 * real_num_tx_queues != 0. */
+		return skb_get_rx_queue(skb) % qcount;
 	}
 
 	if (dev->num_tc) {
-- 
1.8.3.1
