Subject: Re: [Patch RFC 36/37] fs: Convert bd_mount_sem to mutex
From: Daniel Walker <dwalker@fifo99.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@infradead.org>, LKML <linux-kernel@vger.kernel.org>,
       matthias@kaehlcke.net, Andrew Morton <akpm@linux-foundation.org>,
       Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <peterz@infradead.org>,
       Al Viro <viro@zeniv.linux.org.uk>
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Date: Mon, 27 Jul 2009 09:42:28 -0700
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On Mon, 2009-07-27 at 17:30 +0200, Thomas Gleixner wrote:
> On Mon, 27 Jul 2009, Christoph Hellwig wrote:
> 
> > On Sun, Jul 26, 2009 at 08:20:38AM -0000, Thomas Gleixner wrote:
> > > bd_mount_sem is used as mutex so make it a mutex.
> > 
> > Actually we may return to userspace with it held, so the conversion
> > is a bad idea.  But I have a patch I need to post to completely get
> > rid of it.
> 
> That's why it's RFC :)

You better inspect these at much greater detail.. Matthias (added to the
CC) , and I did a great number of semaphore to mutex changes and I don't
recall there being too many clear easy ones remaining .. So unless the
semaphore was added in the past 12 months or so , I'd treat it as likely
unsafe for converting to a mutex..

Daniel

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