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Subject: Re: [RFC 2/4] Deactivate mmap_sem assert
To: Peter Zijlstra <peterz@infradead.org>
References: <cover.1492595897.git.ldufour@linux.vnet.ibm.com>
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From: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Date: Wed, 19 Apr 2017 15:45:50 +0200
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On 19/04/2017 14:30, Peter Zijlstra wrote:
> On Wed, Apr 19, 2017 at 02:18:25PM +0200, Laurent Dufour wrote:
>> When mmap_sem will be moved to a range lock, some assertion done in
>> the code are no more valid, like the one ensuring mmap_sem is held.
>>
> 
> Why are they no longer valid?

I didn't explain that very well..

When using a range lock we can't check that the lock is simply held, but
if the range we are interesting on is locked or not.

As I mentioned this patch will have to be reverted / reviewed once the
range lock is providing dedicated APIs, but some check might be
difficult to adapt to a range.