diff mbox

gpiolib: unexport requested gpios on gpiochip removal

Message ID 1433946861-22371-1-git-send-email-bgolaszewski@baylibre.com
State New
Headers show

Commit Message

Bartosz Golaszewski June 10, 2015, 2:34 p.m. UTC
When a GPIO expander device is removed - e.g. via i2c-adapter
new_device/delete_device interface - with some GPIOs still requested,
gpiochip_remove() function will emit a warning but remove the chip
anyway.

If we then reinstantiate this device and try to export any of the GPIOs
still requested on gpiochip deletion the following warning will be
emitted:

WARNING: CPU: 0 PID: 90 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x58/0x78()
sysfs: cannot create duplicate filename '/class/gpio/gpio504'
Modules linked in: gpio_pca953x ipv6
CPU: 0 PID: 90 Comm: sh Not tainted 4.0.0 #1
Hardware name: Generic AM33XX (Flattened Device Tree)
[<c0015ba0>] (unwind_backtrace) from [<c00121f4>] (show_stack+0x10/0x14)
[<c00121f4>] (show_stack) from [<c0592fb4>] (dump_stack+0x84/0x9c)
[<c0592fb4>] (dump_stack) from [<c003e6c8>] (warn_slowpath_common+0x7c/0xb8)
[<c003e6c8>] (warn_slowpath_common) from [<c003e734>] (warn_slowpath_fmt+0x30/0x40)
[<c003e734>] (warn_slowpath_fmt) from [<c01b7e48>] (sysfs_warn_dup+0x58/0x78)
[<c01b7e48>] (sysfs_warn_dup) from [<c01b815c>] (sysfs_do_create_link_sd.isra.2+0xb0/0xb8)
[<c01b815c>] (sysfs_do_create_link_sd.isra.2) from [<c03ab030>] (device_add+0x1e4/0x510)
[<c03ab030>] (device_add) from [<c03ab4e0>] (device_create_groups_vargs+0x9c/0xc0)
[<c03ab4e0>] (device_create_groups_vargs) from [<c03ab57c>] (device_create_with_groups+0x24/0x2c)
[<c03ab57c>] (device_create_with_groups) from [<c0353000>] (gpiod_export+0xf8/0x224)
[<c0353000>] (gpiod_export) from [<c035317c>] (export_store+0x50/0xd0)
[<c035317c>] (export_store) from [<c03ae200>] (class_attr_store+0x18/0x24)
[<c03ae200>] (class_attr_store) from [<c01b778c>] (sysfs_kf_write+0x4c/0x50)
[<c01b778c>] (sysfs_kf_write) from [<c01b69d0>] (kernfs_fop_write+0xbc/0x1a4)
[<c01b69d0>] (kernfs_fop_write) from [<c014d6fc>] (vfs_write+0xa4/0x1b0)
[<c014d6fc>] (vfs_write) from [<c014dd64>] (SyS_write+0x40/0x94)
[<c014dd64>] (SyS_write) from [<c000e6e0>] (ret_fast_syscall+0x0/0x4c)

sysfs_do_create_link_sd() fails due to dangling links in /sys/class/gpio
rendering these GPIOs unusable until reboot.

Instead of warning the user, just silently unexport all requested GPIOs.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 drivers/gpio/gpiolib.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Johan Hovold June 10, 2015, 5:29 p.m. UTC | #1
Hi Bartosz,

On Wed, Jun 10, 2015 at 04:34:21PM +0200, Bartosz Golaszewski wrote:
> When a GPIO expander device is removed - e.g. via i2c-adapter
> new_device/delete_device interface - with some GPIOs still requested,
> gpiochip_remove() function will emit a warning but remove the chip
> anyway.
> 
> If we then reinstantiate this device and try to export any of the GPIOs
> still requested on gpiochip deletion the following warning will be
> emitted:

For GPIOs exported through sysfs, this has already been fixed by commit
483d82110879 ("gpio: sysfs: fix memory leaks and device hotplug"), which
has also been backported to stable.

Thanks,
Johan
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diff mbox

Patch

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 6bc612b..74a5e45 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -342,7 +342,7 @@  void gpiochip_remove(struct gpio_chip *chip)
 	spin_lock_irqsave(&gpio_lock, flags);
 	for (id = 0; id < chip->ngpio; id++) {
 		if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags))
-			dev_crit(chip->dev, "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
+			gpiod_unexport(&chip->desc[id]);
 	}
 	for (id = 0; id < chip->ngpio; id++)
 		chip->desc[id].chip = NULL;