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

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Message-ID: <20160617082559.GD30935@twins.programming.kicks-ass.net>
Date:	Fri, 17 Jun 2016 10:25:59 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Oleg Drokin <green@...uxhacker.ru>
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 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.