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From: Alex Courbot <acourbot@nvidia.com>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Alexandre Courbot <gnurou@gmail.com>
Subject: Re: [PATCH] gpiolib: Fix locking on gpio debugfs files
Date: Mon, 11 Feb 2013 13:28:38 +0900	[thread overview]
Message-ID: <51187376.2060106@nvidia.com> (raw)
In-Reply-To: <1360406062-14982-1-git-send-email-grant.likely@secretlab.ca>

On 02/09/2013 07:34 PM, Grant Likely wrote:
> The debugfs files really need to hold the gpiolib spinlock before
> accessing the list. Otherwise chip addition/removal will cause an oops.
>
> Cc: Alexandre Courbot <acourbot@nvidia.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

Tested-by: Alexandre Courbot <acourbot@nvidia.com>

Just wondering: if we manage to change this spinlock into a mutex in the 
future, wouldn't it be better to acquire it only once in 
gpiolib_seq_start() and release it in gpiolib_seq_stop()?

Even though the protection introduced by this patch definitely improves 
the situation, it seems to me that chips could still be removed while 
being displayed by gpiolib_seq_show().

Thanks,
Alex.

  reply	other threads:[~2013-02-11  4:26 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-09 10:34 [PATCH] gpiolib: Fix locking on gpio debugfs files Grant Likely
2013-02-11  4:28 ` Alex Courbot [this message]
2013-02-11 11:31   ` Grant Likely
2013-02-12  2:27     ` Alexandre Courbot
2013-02-11 14:31 ` Linus Walleij

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