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Date: Wed, 6 Jun 2007 21:17:29 +0200
From: Jens Axboe <jens.axboe@oracle.com>
To: "Raz Ben-Jehuda(caro)" <raziebe@gmail.com>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: kmap_atomic in 2.6.20.x
Message-ID: <20070606191729.GE4735@kernel.dk>
References: <5d96567b0706061003r462c324i733ad3698ac3d90c@mail.gmail.com>
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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