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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andrew Morton <akpm@osdl.org>, Zachary Amsden <zach@vmware.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Fix kunmap_atomic's use of kpte_clear_flush()
Date: Tue, 07 Nov 2006 17:10:52 -0800	[thread overview]
Message-ID: <45512E9C.9030702@goop.org> (raw)
In-Reply-To: <1162946572.29130.9.camel@localhost.localdomain>

Rusty Russell wrote:
> On Tue, 2006-11-07 at 16:22 -0800, Jeremy Fitzhardinge wrote:
>   
>> kunmap_atomic() will call kpte_clear_flush with vaddr/ptep arguments
>> which don't correspond if the vaddr is just a normal lowmem address
>> (ie, not in the KMAP area).  This patch makes sure that the pte is
>> only cleared if kmap area was actually used for the mapping.
>>     
>
> Or in other words, if kmap_atomic() does nothing, kunmap_atomic() should
> do nothing.
>   

Sure.  I guess there's no particular reason why kmap_atomic() couldn't 
always map, but I guess avoid the pagetable updates is worthwhile.

    J

      reply	other threads:[~2006-11-08  1:10 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-11-08  0:22 [PATCH] Fix kunmap_atomic's use of kpte_clear_flush() Jeremy Fitzhardinge
2006-11-08  0:42 ` Zachary Amsden
2006-11-08  0:42 ` Rusty Russell
2006-11-08  1:10   ` Jeremy Fitzhardinge [this message]

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