centos man page for __netdev_alloc_skb

__NETDEV_ALLOC_SKB(9)						 Linux Networking					     __NETDEV_ALLOC_SKB(9)

NAME
       __netdev_alloc_skb - allocate an skbuff for rx on a specific device

SYNOPSIS
       struct sk_buff * __netdev_alloc_skb(struct net_device * dev, unsigned int length, gfp_t gfp_mask);

ARGUMENTS
       dev
	   network device to receive on

       length
	   length to allocate

       gfp_mask
	   get_free_pages mask, passed to alloc_skb

DESCRIPTION
       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.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014						     __NETDEV_ALLOC_SKB(9)