Re: kmap_atomic in 2.6.20.x

From: Jens Axboe
Date: Wed Jun 06 2007 - 15:10:56 EST


On Wed, Jun 06 2007, Raz Ben-Jehuda(caro) wrote:
> Hello
>
> I am running into some problems with kmap_atomic in my driver.
> My driver copies some pages coming from
> user space to "kernel space kmalloc'ed memory".
> I had this code running from 2.6.5 to 2.6.17 without any problems.
> I have upgraded to 2.6.20.xx and this code fails to kmap_atomic.
> I am running a uni processor 2 GRAM machine, 32bit.
>
> Basically this is code does:
>
> get_user_pages(page,...)
>
> kmap_atomic(page,KM_USER0);
> .. copy and stuff
> kunmap_atomic(page,KM_USER0)

dst = kmap_atomic(page, KM_USER0);
...
kunmap_atomic(dst, KM_USER0);

Note the subtle difference.

--
Jens Axboe

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