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Date: Thu, 28 Aug 2008 00:45:11 +0400
From: Alexey Dobriyan <adobriyan@gmail.com>
To: Jonathan Corbet <corbet@lwn.net>
Cc: LKML <linux-kernel@vger.kernel.org>, Greg KH <greg@kroah.com>,
       hjk@linutronix.de
Subject: Re: [PATCH, RFC] uio BKL removal
Message-ID: <20080827204511.GA31638@x200.localdomain>
References: <20080826171532.2414c7a2@bike.lwn.net>
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On Tue, Aug 26, 2008 at 05:15:32PM -0600, Jonathan Corbet wrote:
> UIO: BKL removal
> 
> Remove the BKL from the UIO driver, and add complete locking where needed
> to serialize idr accesses.

> --- a/drivers/uio/uio.c
> +++ b/drivers/uio/uio.c
> @@ -47,6 +47,9 @@ static struct uio_class {
>  	struct class *class;
>  } *uio_class;
>  
> +/* Protect idr accesses */

You can rename it to uio_idr_mutex (it's mutex, dammit!) and put next to
uio_idr and avoid comment ;-) Or if locking around _pre_get() isn't
necessary you can actually make it spinlock ;-) Anyway, put it close.

> +static DEFINE_MUTEX(minor_lock);

Indeed, BKL protects nothing because of GFP_KERNEL allocation.