Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation

linux-os (Dick Johnson)
2005-12-15T16:22:48Z

On Thu, 15 Dec 2005, David Howells wrote:

> Nikita Danilov <nikita@clusterfs.com> wrote:
>
>> And to convert almost all calls to down/up to mutex_{down,up}. At which
>> point, it no longer makes sense to share the same data-type for
>> semaphore and mutex.
>
> But what to do about DECLARE_MUTEX? :-/
>
> David

Isn't "struct semaphore" already an opaque type. Nobody, except
the optimizer wizards, should even care what's in them. They are
already manipulated with init_MUTEX, up, down, etc. There shouldn't
be any code changes if the actual internal workings are changed.

If some code is peeking into the internal workings, then it's
broken. Don't break the whole kernel by a name-change. Sharing
the same data-type, as long as there are no alignment problems,
has no negative impact at all. If there is stuff inside those
structures that is not used for a particular instance, who cares?
Somebody doing debugging? If they are doing kernel debugging,
they should know what they are doing, you don't dumb-down the
kernel to the lowest common denominator because there may be
different structure members used for different purposes!

Cheers,
Dick Johnson
Penguin : Linux version 2.6.13.4 on an i686 machine (5589.56 BogoMips).
Warning : 98.36% of all statistics are fiction.
.

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