linux-kernel - Re: initialize a mutex into locked state?

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Message-Id: <38111D58-C42F-4ED3-BC31-04884795BE38@linuxhacker.ru>
Date:	Fri, 17 Jun 2016 10:14:10 -0400
From:	Oleg Drokin <green@...uxhacker.ru>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Mailing List <linux-kernel@...r.kernel.org>, mingo@...hat.com,
	arjan@...ux.intel.com, "J . Bruce Fields" <bfields@...ldses.org>,
	Jeff Layton <jlayton@...chiereds.net>
Subject: Re: initialize a mutex into locked state?


On Jun 17, 2016, at 4:25 AM, Peter Zijlstra wrote:

> On Wed, Jun 15, 2016 at 02:23:35PM -0400, Oleg Drokin wrote:
>> Hello!
>> 
>>  To my surprise I found out that it's not possible to initialise a mutex into
>>  a locked state.
>>  I discussed it with Arjan and apparently there's no fundamental reason
>>  not to allow this.
> 
> There is. A mutex _must_ have an owner. If you can initialize it in
> locked state, you could do so statically, ie. outside of the context of
> a task.

What's wrong with disallowing only static initializers, but allowing dynamic ones?
Then there is a clear owner.