linux-kernel - Re: [PATCH v3] pinctrl: move subsystem mutex to pinctrl

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Date:	Mon, 27 May 2013 15:57:13 +0200
From:	Linus Walleij <linus.walleij@...aro.org>
To:	James Hogan <james.hogan@...tec.com>
Cc:	Linus Walleij <linus.walleij@...ricsson.com>,
	Patrice Chotard <patrice.chotard@...com>,
	LKML <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Stephen Warren <swarren@...dia.com>,
	Anmar Oueja <anmar.oueja@...aro.org>,
	Laurent Meunier <laurent.meunier@...com>
Subject: Re: [PATCH v3] pinctrl: move subsystem mutex to pinctrl_dev struct

On Fri, May 24, 2013 at 5:22 PM, James Hogan <james.hogan@...tec.com> wrote:
> On 26 April 2013 16:08, Linus Walleij <linus.walleij@...ricsson.com> wrote:
>> @@ -608,7 +610,7 @@ static int pinconf_dbg_config_print(struct seq_file *s, void *d)
>>         bool found = false;
>>         unsigned long config;
>>
>> -       mutex_lock(&pinctrl_mutex);
>> +       mutex_lock(&pctldev->mutex);
>>
>>         /* Parse the pinctrl map and look for the elected pin/state */
>>         for_each_maps(maps_node, i, map) {
>
> This change causes an oops on v3.10-rc2 when you read pinconf-config
> because pctldev is initialised to NULL and not set until inside the
> loop.

It is taking the wrong mutex. The function right below it is
also iterating the maps, and then it shall take the maps
mutex and nothing else.

I just sent a patch fixing it up.

> If this debugfs file
> isn't meant to be specific to a pinctrl device should it be in the
> root pinctrl directory instead of in each pinctrl device's directory?

Yes. We need to fix this after this immediate fixup, for the next
merge window.

Yours,
Linus Walleij
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