bnx2x: Take the distribution range definition out of skb_tx_hash()

Move the calcualation of the Tx hash for a given hash range into a separate
function and define the skb_tx_hash(), which calculates a Tx hash for a
[0; dev->real_num_tx_queues - 1] hash values range, using this
function (__skb_tx_hash()).
Signed-off-by: Vladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -1747,6 +1747,16 @@ static inline void netif_wake_subqueue(struct net_device *dev, u16 queue_index)
 		__netif_schedule(txq->qdisc);
 }
 
+/*
+ * Returns a Tx hash for the given packet when dev->real_num_tx_queues is used
+ * as a distribution range limit for the returned value.
+ */
+static inline u16 skb_tx_hash(const struct net_device *dev,
+			      const struct sk_buff *skb)
+{
+	return __skb_tx_hash(dev, skb, dev->real_num_tx_queues);
+}
+
 /**
  *	netif_is_multiqueue - test if device has multiple transmit queues
  *	@dev: network device

include/linux/skbuff.h

@@ -2165,8 +2165,9 @@ static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
 	return skb->queue_mapping != 0;
 }
 
-extern u16 skb_tx_hash(const struct net_device *dev,
-		       const struct sk_buff *skb);
+extern u16 __skb_tx_hash(const struct net_device *dev,
+			 const struct sk_buff *skb,
+			 unsigned int num_tx_queues);
 
 #ifdef CONFIG_XFRM
 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)

net/core/dev.c

@@ -2112,14 +2112,19 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
 
 static u32 hashrnd __read_mostly;
 
-u16 skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb)
+/*
+ * Returns a Tx hash based on the given packet descriptor a Tx queues' number
+ * to be used as a distribution range.
+ */
+u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb,
+		  unsigned int num_tx_queues)
 {
 	u32 hash;
 
 	if (skb_rx_queue_recorded(skb)) {
 		hash = skb_get_rx_queue(skb);
-		while (unlikely(hash >= dev->real_num_tx_queues))
-			hash -= dev->real_num_tx_queues;
+		while (unlikely(hash >= num_tx_queues))
+			hash -= num_tx_queues;
 		return hash;
 	}
 
@@ -2129,9 +2134,9 @@ u16 skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb)
 		hash = (__force u16) skb->protocol ^ skb->rxhash;
 	hash = jhash_1word(hash, hashrnd);
 
-	return (u16) (((u64) hash * dev->real_num_tx_queues) >> 32);
+	return (u16) (((u64) hash * num_tx_queues) >> 32);
 }
-EXPORT_SYMBOL(skb_tx_hash);
+EXPORT_SYMBOL(__skb_tx_hash);
 
 static inline u16 dev_cap_txqueue(struct net_device *dev, u16 queue_index)
 {