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Date: Sat, 17 Oct 2009 19:07:20 +0200
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Jonathan Cameron <jic23@cam.ac.uk>
Cc: LKML <linux-kernel@vger.kernel.org>, Zhang Rui <rui.zhang@intel.com>,
       Jean Delvare <khali@linux-fr.org>,
       Rodolfo Giometti <giometti@enneenne.com>,
       "Michele De Candia (VT)" <michele.decandia@valueteam.com>,
       Linux I2C <linux-i2c@vger.kernel.org>
Subject: Re: [PATCH V2] ALS: TSL2550 driver move from i2c/chips
Message-ID: <20091017170718.GB10344@nowhere>
References: <4AD9F750.9090800@cam.ac.uk>
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On Sat, Oct 17, 2009 at 05:56:48PM +0100, Jonathan Cameron wrote:
> +static int tsl2550_get_id(void)
> +{
> +	int ret, val;
> +
> +idr_again:
> +	if (unlikely(idr_pre_get(&tsl2550_idr, GFP_KERNEL) == 0))
> +		return -ENOMEM;
> +	spin_lock(&tsl2550_idr_lock);
> +	ret = idr_get_new(&tsl2550_idr, NULL, &val);
> +	if (unlikely(ret == -EAGAIN))
> +		goto idr_again;


That looks like a fair chance to produce a deadlock
by reacquiring the above spinlock.

Also I never see the above lock released later from this
function or its caller.

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