spans_boundary(9) centos man page | unix.com

SPANS_BOUNDARY(9)						Internal Functions						 SPANS_BOUNDARY(9)

NAME
       spans_boundary - Check a packet can be ISA DMA'd

SYNOPSIS
       int spans_boundary(struct sk_buff * skb);

ARGUMENTS
       skb
	   The buffer to check

DESCRIPTION
       Returns true if the buffer cross a DMA boundary on a PC. The poor thing can only DMA within a 64K block not across the edges of it.

AUTHOR
       Alan Cox <alan@lxorguk.ukuu.org.uk>
	   Author.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014							 SPANS_BOUNDARY(9)