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Date: Mon, 13 Jun 2005 12:54:40 -0700
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To: Christoph Hellwig <hch@infradead.org>
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Cc: Daniel Eischen <deischen@freebsd.org>, freebsd-hackers@freebsd.org,
	Scott Long <scottl@samsco.org>, Apache Xie <apachexm@hotmail.com>
Subject: Re: contigmalloc() and mmap()
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Christoph Hellwig wrote:

>On Mon, Jun 13, 2005 at 12:55:40PM -0600, Scott Long wrote:
>  
>
>>>Lot's of driver use file->private to get at per-device data easily,
>>>but that's just a shortcut.
>>>      
>>>
>>Ok, I thought that you were talking about per-process data being in the
>>file descriptor.
>>    
>>
>
>No, Linux has absolutely no concept of per-process data in driver, and
>if you think of it that would be rather bogus anyway (e.g. a driver opening
>the same device multiple times)
>  
>

though, some people use it for that purpose (e.g. in the original posting).

it might not be such a bad idea..
I don't see why the device entrypoints shouldn't have that argument
available.. (file descriptor by which we are getting here)
As long as it can take account of the fact that not all accesses come 
via an FD
(e.g mounted disks).