Re: mmaping a kernel buffer to user space

On 10/31/06, Jiri Slaby <jirislaby@xxxxxxxxx> wrote:
Guillermo Marcus wrote:
> Hi Jiri,
>
> The fact that it does not works with RAM is well documented in LDD3,
> pages 430++. It says (and I tested) that remap_xxx_range does not work
> in this case. They suggest a method using nopage, similar to the one I
> implement.

Could somebody confirm, that this still holds?


Hum, I also tried it some days ago and it didn't work for me, so I
read LDD3 and I found such explanation about such limitation of
remap_pfn_range(). I heard then that changed in 2.6.15 because of the
new flag; so I have had the same situation.

If it is possible to remap a kernel buffer to userspace with
remap_pfn_range, how should be done the right way?

> I do not see why remap_xxx_range has the limitation, but it is there.
> The question is then: can the limitation be removed, or can we implement
> a new function that maps RAM all at once without the need for a nopage
> implementation?
>
> In any case, here is the code.

Hmm, interesting. I used remap_pfn_range for this purpose today and it worked (I
double-checked this). I should probably do the rework :(.

regards,

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