[Fwd: remap_page_range() vs nopage()]

[Fwd: remap_page_range() vs nopage()]

[Michel Hubert]

Hello, 

I previously posted this question to kernelnewbies.org but without 
getting any answer.  I hope it is not too basic for this mailing list...

It's written in Linux Device Driver 2nd edition that remap_page_range
(which maps an entire range at once) should be used for device IO
whereas nopage (which maps a single page at a time) should be used for
real physical memory.

However, I noticed that mmap_mem() in drivers/char/mem.c uses
exclusively remap_page_range.  How could this work when dealing with non
contiguous physical memory ?

Thank you, 

Michel


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Re: [Fwd: remap_page_range() vs nopage()]

[William Lee Irwin III]

On Wed, Jul 14, 2004 at 06:43:06PM -0400, Michel Hubert wrote:
> I previously posted this question to kernelnewbies.org but without 
> getting any answer.  I hope it is not too basic for this mailing list...
> It's written in Linux Device Driver 2nd edition that remap_page_range
> (which maps an entire range at once) should be used for device IO
> whereas nopage (which maps a single page at a time) should be used for
> real physical memory.
> However, I noticed that mmap_mem() in drivers/char/mem.c uses
> exclusively remap_page_range.  How could this work when dealing with non
> contiguous physical memory ?

I gave up on fixing this and the highmem issue with mem.c a while ago.
There's holy penguin pee here, beware.


-- wli
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