[v2,05/23] gpio: sysfs: reduce gpiochip-export locking scope
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Message ID 1430752248-15401-6-git-send-email-johan@kernel.org
State New
Headers show

Commit Message

Johan Hovold May 4, 2015, 3:10 p.m. UTC
Reduce scope of sysfs_lock protection during chip export and unexport,
which is only needed to prevent gpiod (re-)exports during chip removal.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/gpio/gpiolib-sysfs.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Comments

Linus Walleij May 12, 2015, 8:05 a.m. UTC | #1
On Mon, May 4, 2015 at 5:10 PM, Johan Hovold <johan@kernel.org> wrote:

> Reduce scope of sysfs_lock protection during chip export and unexport,
> which is only needed to prevent gpiod (re-)exports during chip removal.
>
> Signed-off-by: Johan Hovold <johan@kernel.org>

Patch applied with some manual interventions.
Pls check result!

Yours,
Linus Walleij
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Patch
diff mbox

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 658ed28e6d7d..d19bf234e878 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -779,7 +779,6 @@  int gpiochip_export(struct gpio_chip *chip)
 		return 0;
 
 	/* use chip->base for the ID; it's already known to be unique */
-	mutex_lock(&sysfs_lock);
 	dev = device_create_with_groups(&gpio_class, chip->dev, MKDEV(0, 0),
 					chip, gpiochip_groups,
 					"gpiochip%d", chip->base);
@@ -787,6 +786,8 @@  int gpiochip_export(struct gpio_chip *chip)
 		status = PTR_ERR(dev);
 	else
 		status = 0;
+
+	mutex_lock(&sysfs_lock);
 	chip->exported = (status == 0);
 	mutex_unlock(&sysfs_lock);
 
@@ -803,17 +804,17 @@  void gpiochip_unexport(struct gpio_chip *chip)
 	struct gpio_desc *desc;
 	unsigned int i;
 
-	mutex_lock(&sysfs_lock);
 	dev = class_find_device(&gpio_class, NULL, chip, match_export);
 	if (dev) {
 		put_device(dev);
 		device_unregister(dev);
 		/* prevent further gpiod exports */
+		mutex_lock(&sysfs_lock);
 		chip->exported = false;
+		mutex_unlock(&sysfs_lock);
 		status = 0;
 	} else
 		status = -ENODEV;
-	mutex_unlock(&sysfs_lock);
 
 	if (status)
 		chip_dbg(chip, "%s: status %d\n", __func__, status);