skb: expose and constify hash primitives

Some minor changes to queue hashing:
 1. Use const on accessor functions
 2. Export skb_tx_hash for use in drivers (see ixgbe)

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 8 insertions, 4 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 1fbab2ae613c..bb1981fd60f3 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1969,7 +1969,7 @@ static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
         skb->queue_mapping = queue_mapping;
 }
 
-static inline u16 skb_get_queue_mapping(struct sk_buff *skb)
+static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
 {
         return skb->queue_mapping;
 }
@@ -1984,16 +1984,19 @@ static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
         skb->queue_mapping = rx_queue + 1;
 }
 
-static inline u16 skb_get_rx_queue(struct sk_buff *skb)
+static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
 {
         return skb->queue_mapping - 1;
 }
 
-static inline bool skb_rx_queue_recorded(struct sk_buff *skb)
+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);
+
 #ifdef CONFIG_XFRM
 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
 {
diff --git a/net/core/dev.c b/net/core/dev.c
index ca212acd3348..fdb9973b82a6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1725,7 +1725,7 @@ out_kfree_skb:
 
 static u32 skb_tx_hashrnd;
 
-static u16 skb_tx_hash(struct net_device *dev, struct sk_buff *skb)
+u16 skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb)
 {
         u32 hash;
 
@@ -1740,6 +1740,7 @@ static u16 skb_tx_hash(struct net_device *dev, struct sk_buff *skb)
 
         return (u16) (((u64) hash * dev->real_num_tx_queues) >> 32);
 }
+EXPORT_SYMBOL(skb_tx_hash);
 
 static struct netdev_queue *dev_pick_tx(struct net_device *dev,
                                         struct sk_buff *skb)