[PATCH] libio: Remove special-case reference count

[Sebastian Huber]

On 11/09/17 20:34, Gedare Bloom wrote:
> On Fri, Sep 8, 2017 at 1:04 AM, Sebastian Huber
> <sebastian.huber at embedded-brains.de>  wrote:
>> On 08/09/17 00:08, Gedare Bloom wrote:
>>
>>> I understand the motivation. I need to look carefully at whether this
>>> breaks the special case, and how to otherwise fix it.
>> The change didn't introduce test suite failures.
>>
> Yeah, I neglected to create a test case for this. When I can, I will.
> The language at issue here from the standard is:
> "The mmap() function shall add an extra reference to the file
> associated with the file descriptor fildes which is not removed by a
> subsequent close() on that file descriptor. This reference shall be
> removed when there are no more mappings to the file."

Yes, this sounds reasonable especially since it says

"... shall add an extra reference to the file associated with ..."

It doesn't say

"... shall add an extra reference to the file descriptor ..."

This is in line with the IO library (without your mapping specific file 
descriptor reference counting) which delegates the file (node) specific 
reference counting to the file system support. You do this for example 
in your share memory support via POSIX_Shm_Control::reference_count.

-- 
Sebastian Huber, embedded brains GmbH

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