Commit 6efcfe10 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'gpio-fixes-for-v6.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux 

Pull gpio fixes from Bartosz Golaszewski:
 "The first fix is a backport from my v6.15-rc1 queue that turned out to
  be needed in v6.14 as well but as the former diverged from my fixes
  branch I had to adjust the patch a bit.

  The second one fixes a regression observed in user-space where closing
  a file descriptor associated with a GPIO device results in a ~10ms
  delay due to the atomic notifier calling rcu_synchronize() when
  unregistering.

  Summary:

   - don't check the return value of gpio_chip::get_direction() when
     registering a GPIO chip

   - use raw notifier for line state events"

* tag 'gpio-fixes-for-v6.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
  gpio: cdev: use raw notifier for line state events
  gpiolib: don't check the retval of get_direction() when registering a chip
parents b1144bc7 dcb73cba

drivers/gpio/gpiolib-cdev.c

+9 −6
Original line number Diff line number Diff line
@@ -2729,7 +2729,8 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file) 
	cdev->gdev = gpio_device_get(gdev);



	cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;

	ret = atomic_notifier_chain_register(&gdev->line_state_notifier,

	scoped_guard(write_lock_irqsave, &gdev->line_state_lock)

		ret = raw_notifier_chain_register(&gdev->line_state_notifier,

						  &cdev->lineinfo_changed_nb);

	if (ret)

		goto out_free_bitmap;
@@ -2754,7 +2755,8 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file) 
	blocking_notifier_chain_unregister(&gdev->device_notifier,

					   &cdev->device_unregistered_nb);

out_unregister_line_notifier:

	atomic_notifier_chain_unregister(&gdev->line_state_notifier,

	scoped_guard(write_lock_irqsave, &gdev->line_state_lock)

		raw_notifier_chain_unregister(&gdev->line_state_notifier,

					      &cdev->lineinfo_changed_nb);

out_free_bitmap:

	gpio_device_put(gdev);
@@ -2779,7 +2781,8 @@ static int gpio_chrdev_release(struct inode *inode, struct file *file) 


	blocking_notifier_chain_unregister(&gdev->device_notifier,

					   &cdev->device_unregistered_nb);

	atomic_notifier_chain_unregister(&gdev->line_state_notifier,

	scoped_guard(write_lock_irqsave, &gdev->line_state_lock)

		raw_notifier_chain_unregister(&gdev->line_state_notifier,

					      &cdev->lineinfo_changed_nb);

	bitmap_free(cdev->watched_lines);

	gpio_device_put(gdev);

drivers/gpio/gpiolib.c

+16 −19
Original line number Diff line number Diff line
@@ -1025,7 +1025,8 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, 
		}

	}



	ATOMIC_INIT_NOTIFIER_HEAD(&gdev->line_state_notifier);

	rwlock_init(&gdev->line_state_lock);

	RAW_INIT_NOTIFIER_HEAD(&gdev->line_state_notifier);

	BLOCKING_INIT_NOTIFIER_HEAD(&gdev->device_notifier);



	ret = init_srcu_struct(&gdev->srcu);
@@ -1056,25 +1057,20 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, 


		desc->gdev = gdev;



		if (gc->get_direction && gpiochip_line_is_valid(gc, desc_index)) {

			ret = gc->get_direction(gc, desc_index);

			if (ret < 0)

		/*

				 * FIXME: Bail-out here once all GPIO drivers

				 * are updated to not return errors in

				 * situations that can be considered normal

				 * operation.

				 */

				dev_warn(&gdev->dev,

					 "%s: get_direction failed: %d\n",

					 __func__, ret);



			assign_bit(FLAG_IS_OUT, &desc->flags, !ret);

		} else {

		 * We would typically want to check the return value of

		 * get_direction() here but we must not check the return value

		 * and bail-out as pin controllers can have pins configured to

		 * alternate functions and return -EINVAL. Also: there's no

		 * need to take the SRCU lock here.

		 */

		if (gc->get_direction && gpiochip_line_is_valid(gc, desc_index))

			assign_bit(FLAG_IS_OUT, &desc->flags,

				   !gc->get_direction(gc, desc_index));

		else

			assign_bit(FLAG_IS_OUT,

				   &desc->flags, !gc->direction_input);

	}

	}



	ret = of_gpiochip_add(gc);

	if (ret)
@@ -4193,8 +4189,9 @@ EXPORT_SYMBOL_GPL(gpiod_set_array_value_cansleep); 


void gpiod_line_state_notify(struct gpio_desc *desc, unsigned long action)

{

	atomic_notifier_call_chain(&desc->gdev->line_state_notifier,

				   action, desc);

	guard(read_lock_irqsave)(&desc->gdev->line_state_lock);



	raw_notifier_call_chain(&desc->gdev->line_state_notifier, action, desc);

}



/**

drivers/gpio/gpiolib.h

+4 −1
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/gpio/driver.h>

#include <linux/module.h>

#include <linux/notifier.h>

#include <linux/spinlock.h>

#include <linux/srcu.h>

#include <linux/workqueue.h>
@@ -45,6 +46,7 @@ 
 * @list: links gpio_device:s together for traversal

 * @line_state_notifier: used to notify subscribers about lines being

 *                       requested, released or reconfigured

 * @line_state_lock: RW-spinlock protecting the line state notifier

 * @line_state_wq: used to emit line state events from a separate thread in

 *                 process context

 * @device_notifier: used to notify character device wait queues about the GPIO
@@ -72,7 +74,8 @@ struct gpio_device { 
	const char		*label;

	void			*data;

	struct list_head        list;

	struct atomic_notifier_head line_state_notifier;

	struct raw_notifier_head line_state_notifier;

	rwlock_t		line_state_lock;

	struct workqueue_struct	*line_state_wq;

	struct blocking_notifier_head device_notifier;

	struct srcu_struct	srcu;