suse man page for follow_pfn

FOLLOW_PFN(9)						    Memory Management in Linux						     FOLLOW_PFN(9)

NAME
       follow_pfn - look up PFN at a user virtual address

SYNOPSIS
       int follow_pfn(struct vm_area_struct * vma, unsigned long address, unsigned long * pfn);

ARGUMENTS
       vma
	   memory mapping

       address
	   user virtual address

       pfn
	   location to store found PFN

DESCRIPTION
       Only IO mappings and raw PFN mappings are allowed.

       Returns zero and the pfn at pfn on success, -ve otherwise.

COPYRIGHT
Kernel Hackers Manual 2.6.					     July 2010							     FOLLOW_PFN(9)