[NET]: Add netdev_alloc_skb().

Add a dev_alloc_skb variant that takes a struct net_device * paramater.
For now that paramater is unused, but I'll use it to allocate the skb
from node-local memory in a follow-up patch.  Also there have been some
other plans mentioned on the list that can use it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 0 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 4307e764ef0a..b91fbfb7d54c 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1104,6 +1104,28 @@ static inline struct sk_buff *dev_alloc_skb(unsigned int length)
         return __dev_alloc_skb(length, GFP_ATOMIC);
 }
 
+extern struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
+                unsigned int length, gfp_t gfp_mask);
+
+/**
+ *      netdev_alloc_skb - allocate an skbuff for rx on a specific device
+ *      @dev: network device to receive on
+ *      @length: length to allocate
+ *
+ *      Allocate a new &sk_buff and assign it a usage count of one. The
+ *      buffer has unspecified headroom built in. Users should allocate
+ *      the headroom they think they need without accounting for the
+ *      built in space. The built in space is used for optimisations.
+ *
+ *      %NULL is returned if there is no free memory. Although this function
+ *      allocates memory it can be called from an interrupt.
+ */
+static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
+                unsigned int length)
+{
+        return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
+}
+
 /**
  *      skb_cow - copy header of skb when it is required
  *      @skb: buffer to cow