From: Johan Hovold <johan@kernel.org>
Date: Mon, 4 May 2015 15:10:45 +0000 (+0200)
Subject: gpio: sysfs: fix race between gpiod export and unexport
X-Git-Tag: omap-for-v4.3/legacy-v2-signed~191^2~35
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=72eba6f66a0017356380eec64db8780305aee2b8;p=pandora-kernel.git

gpio: sysfs: fix race between gpiod export and unexport

Make sure to deregister the class device (and release the irq) while
holding the sysfs lock in gpio_unexport to prevent racing with
gpio_export.

Note that this requires the recently introduced per-gpio locking to
avoid a deadlock with the kernfs active protection when waiting for the
attribute operations to drain during deregistration.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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