linux-kernel - [PATCH 3.2 113/152] gpio: sysfs: fix gpio-chip device-attribute leak

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Message-ID: <lsq.1424137613.918623453@decadent.org.uk>
Date:	Tue, 17 Feb 2015 01:46:53 +0000
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org, "Johan Hovold" <johan@...nel.org>,
	"Linus Walleij" <linus.walleij@...aro.org>
Subject: [PATCH 3.2 113/152] gpio: sysfs: fix gpio-chip device-attribute leak

3.2.67-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@...nel.org>

commit 121b6a79955a3a3fd7bbb9b8cb88d5b9dad6283d upstream.

The gpio-chip device attributes were never destroyed when the device was
removed.

Fix by using device_create_with_groups() to create the device attributes
of the chip class device.

Note that this also fixes the attribute-creation race with userspace.

Fixes: d8f388d8dc8d ("gpio: sysfs interface")
Signed-off-by: Johan Hovold <johan@...nel.org>
Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/gpio/gpiolib.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -587,16 +587,13 @@ static ssize_t chip_ngpio_show(struct de
 }
 static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
 
-static const struct attribute *gpiochip_attrs[] = {
+static struct attribute *gpiochip_attrs[] = {
 	&dev_attr_base.attr,
 	&dev_attr_label.attr,
 	&dev_attr_ngpio.attr,
 	NULL,
 };
-
-static const struct attribute_group gpiochip_attr_group = {
-	.attrs = (struct attribute **) gpiochip_attrs,
-};
+ATTRIBUTE_GROUPS(gpiochip);
 
 /*
  * /sys/class/gpio/export ... write-only
@@ -918,13 +915,13 @@ static int gpiochip_export(struct gpio_c
 
 	/* use chip->base for the ID; it's already known to be unique */
 	mutex_lock(&sysfs_lock);
-	dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
-				"gpiochip%d", chip->base);
-	if (!IS_ERR(dev)) {
-		status = sysfs_create_group(&dev->kobj,
-				&gpiochip_attr_group);
-	} else
+	dev = device_create_with_groups(&gpio_class, chip->dev, MKDEV(0, 0),
+					chip, gpiochip_groups,
+					"gpiochip%d", chip->base);
+	if (IS_ERR(dev))
 		status = PTR_ERR(dev);
+	else
+		status = 0;
 	chip->exported = (status == 0);
 	mutex_unlock(&sysfs_lock);
 

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