Re: [patch] mspec - special memory driver and do_no_pfn handler

[Jes Sorensen <jes@sgi.com>]

Carsten Otte wrote:
> Jes Sorensen wrote:
>> Index: linux-2.6/include/linux/mm.h
>> ===================================================================
>> --- linux-2.6.orig/include/linux/mm.h
>> +++ linux-2.6/include/linux/mm.h
>> @@ -199,6 +199,7 @@
>>  	void (*open)(struct vm_area_struct * area);
>>  	void (*close)(struct vm_area_struct * area);
>>  	struct page * (*nopage)(struct vm_area_struct * area, unsigned long address, int *type);
>> +	long (*nopfn)(struct vm_area_struct * area, unsigned long address, int *type);
>>  	int (*populate)(struct vm_area_struct * area, unsigned long address, unsigned long len, pgprot_t prot, unsigned long pgoff, int nonblock);
>>  #ifdef CONFIG_NUMA
>>  	int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
> If you use address as parameter to nopfn, it won't work with highmem
> on 32bit systems. Alternative would be to use (unsigned long) phys. page
> frame number.

Hi Carsten,

The address comes from handle_pte_fault() passing it to do_no_pfn()
passing it to ->nopfn(), ie. it's the faulted address, not the physical
one.

> Your work in memory.c looks like the right thing to do.
> Afaics it will work for xip as well once I figure how to
> do COW. Cool stuff :-).

:-)

Cheers,
Jes