Re: [PATCH 2.6.21] cramfs: add cramfs Linear XIP

[Carsten Otte <cotte@de.ibm.com>]

Jared Hulbert wrote:
>> To me, it looks like this
>> work can be modified to use filemap_xip.
> 
> How?
First, get a struct page behind the subject file system image. A good 
idea to get there is to use vmem_map, which allows have a 
discontiguous mem_map array in virtual storage. Then add the memory 
segment's address range to it. Sparsemem also helps, if vmem_map is 
not available.

Second, implement get_xip_page for this file system. This address 
space operation needs to be provided for all files that are supposed 
to be XIP. readpage(s)/writepage(s) should not be provided for these 
files, becuase they rely on using the page cache.

Third, use file operations from mm/filemap_xip.c.

so long,
Carsten