DESCRIPTION

     This macro maps the page of kernel memory to an  index  into
     the  mem_map  array.  The  input  page  is kernel-space page
     addresses such as those that come from the  get_free_page(9)
     function.  The  expression  mem_map[MAP_NR(page)]  returns a
     pointer to a mem_map_t for the page in question.

     Device drivers need access to the page structure  if  it  is
     implimenting some special kind of memory segment, i.e. cache
     for a virtual frame buffer.

RETURN VALUE

     Returns an index into the mem_map array.

AVAILABILITY

     Linux 2.0+

SEE ALSO

     get_free_pages(9)

     /usr/include/asm/page.h

AUTHOR

     Stephen Williams <steve@icarus.com>

BUGS

     There is no check that the page you are passing really is  a
     valid page address.