Commit be711caa authored by Bartosz Golaszewski's avatar Bartosz Golaszewski
Browse files

gpio: add SRCU infrastructure to struct gpio_desc 



Extend the GPIO descriptor with an SRCU structure in order to serialize
the access to the label. Initialize and clean it up where applicable.

Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Acked-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
parent ccfb6ff4

drivers/gpio/gpiolib.c

+16 −2
Original line number Diff line number Diff line
@@ -672,6 +672,10 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_valid); 
static void gpiodev_release(struct device *dev)

{

	struct gpio_device *gdev = to_gpio_device(dev);

	unsigned int i;



	for (i = 0; i < gdev->ngpio; i++)

		cleanup_srcu_struct(&gdev->descs[i].srcu);



	ida_free(&gpio_ida, gdev->id);

	kfree_const(gdev->label);
@@ -836,7 +840,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, 
			       struct lock_class_key *request_key)

{

	struct gpio_device *gdev;

	unsigned int i;

	unsigned int i, j;

	int base = 0;

	int ret = 0;
@@ -970,6 +974,13 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, 
	for (i = 0; i < gc->ngpio; i++) {

		struct gpio_desc *desc = &gdev->descs[i];



		ret = init_srcu_struct(&desc->srcu);

		if (ret) {

			for (j = 0; j < i; j++)

				cleanup_srcu_struct(&gdev->descs[j].srcu);

			goto err_remove_of_chip;

		}



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

			assign_bit(FLAG_IS_OUT,

				   &desc->flags, !gc->get_direction(gc, i));
@@ -981,7 +992,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, 


	ret = gpiochip_add_pin_ranges(gc);

	if (ret)

		goto err_remove_of_chip;

		goto err_cleanup_desc_srcu;



	acpi_gpiochip_add(gc);
@@ -1020,6 +1031,9 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, 
	gpiochip_irqchip_free_valid_mask(gc);

err_remove_acpi_chip:

	acpi_gpiochip_remove(gc);

err_cleanup_desc_srcu:

	for (i = 0; i < gdev->ngpio; i++)

		cleanup_srcu_struct(&gdev->descs[i].srcu);

err_remove_of_chip:

	gpiochip_free_hogs(gc);

	of_gpiochip_remove(gc);

drivers/gpio/gpiolib.h

+3 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/module.h>

#include <linux/notifier.h>

#include <linux/rwsem.h>

#include <linux/srcu.h>



#define GPIOCHIP_NAME	"gpiochip"
@@ -147,6 +148,7 @@ void gpiod_line_state_notify(struct gpio_desc *desc, unsigned long action); 
 * @label:		Name of the consumer

 * @name:		Line name

 * @hog:		Pointer to the device node that hogs this line (if any)

 * @srcu:		SRCU struct protecting the label pointer.

 *

 * These are obtained using gpiod_get() and are preferable to the old

 * integer-based handles.
@@ -184,6 +186,7 @@ struct gpio_desc { 
#ifdef CONFIG_OF_DYNAMIC

	struct device_node	*hog;

#endif

	struct srcu_struct	srcu;

};



#define gpiod_not_found(desc)		(IS_ERR(desc) && PTR_ERR(desc) == -ENOENT)