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Date: Wed, 14 May 2008 22:17:30 +0100
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>, Ingo Molnar <mingo@elte.hu>,
       linux-kernel@vger.kernel.org,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Thomas Gleixner <tglx@linutronix.de>,
       Alexander Viro <viro@ftp.linux.org.uk>
Subject: Re: [announce] "kill the Big Kernel Lock (BKL)" tree
Message-ID: <20080514221730.5334246d@core>
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> > So you just stick unlock_kernel()/lock_kernel() around the call
> > to TTY (or similar to the entry points)
> > 
> 
> ... assuming that the ISDN code doesn't assume lock continuity across 
> the TTY call.

And procfs and between the tty and the net config code and ...

Keeping the BKL just in legacy places doesn't work. A counting mutex (ie
one you can self multi-lock) might be very useful to fix some of these
however as once we push it down to the point of being a driver specific
lock we can just give it a driver mutex