Re: [patch 4/6] xip: support non-struct page backed memory

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

Linus Torvalds wrote:
> Implementing a kmap_pfn() sounds like a perfectly sane idea. But why does 
> it need to even be mapped into kernel space? Is it for the ELF header 
> reading or something (not having looked at the patch, just reacting to the 
> wrongness of using virt_to_phys())?
It needs to be mapped into kernel space to do regular file operations 
other than mmap. In mm/filemap_xip.c we do access the xip memory from 
kernel to fulfill sys_read/sys_write and friends [copy_from/to_user to 
user's buffer].

so long,
Carsten