1 files changed, 167 insertions, 167 deletions

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 6bf5332136e5..1acfa43bf1ab 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 
 #include <linux/bitops.h>
+#include <linux/cleanup.h>
 #include <linux/device.h>
 #include <linux/idr.h>
 #include <linux/init.h>
@@ -13,12 +14,15 @@
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/string.h>
+#include <linux/srcu.h>
 #include <linux/sysfs.h>
 #include <linux/types.h>
 
 #include <linux/gpio/consumer.h>
 #include <linux/gpio/driver.h>
 
+#include <uapi/linux/gpio.h>
+
 #include "gpiolib.h"
 #include "gpiolib-sysfs.h"
 
@@ -75,12 +79,10 @@ static ssize_t direction_show(struct device *dev,
 	struct gpio_desc *desc = data->desc;
 	int value;
 
-	mutex_lock(&data->mutex);
-
-	gpiod_get_direction(desc);
-	value = !!test_bit(FLAG_IS_OUT, &desc->flags);
-
-	mutex_unlock(&data->mutex);
+	scoped_guard(mutex, &data->mutex) {
+		gpiod_get_direction(desc);
+		value = !!test_bit(FLAG_IS_OUT, &desc->flags);
+	}
 
 	return sysfs_emit(buf, "%s\n", value ? "out" : "in");
 }
@@ -92,7 +94,7 @@ static ssize_t direction_store(struct device *dev,
 	struct gpio_desc *desc = data->desc;
 	ssize_t			status;
 
-	mutex_lock(&data->mutex);
+	guard(mutex)(&data->mutex);
 
 	if (sysfs_streq(buf, "high"))
 		status = gpiod_direction_output_raw(desc, 1);
@@ -103,8 +105,6 @@ static ssize_t direction_store(struct device *dev,
 	else
 		status = -EINVAL;
 
-	mutex_unlock(&data->mutex);
-
 	return status ? : size;
 }
 static DEVICE_ATTR_RW(direction);
@@ -116,11 +116,8 @@ static ssize_t value_show(struct device *dev,
 	struct gpio_desc *desc = data->desc;
 	ssize_t			status;
 
-	mutex_lock(&data->mutex);
-
-	status = gpiod_get_value_cansleep(desc);
-
-	mutex_unlock(&data->mutex);
+	scoped_guard(mutex, &data->mutex)
+		status = gpiod_get_value_cansleep(desc);
 
 	if (status < 0)
 		return status;
@@ -138,18 +135,17 @@ static ssize_t value_store(struct device *dev,
 
 	status = kstrtol(buf, 0, &value);
 
-	mutex_lock(&data->mutex);
+	guard(mutex)(&data->mutex);
 
-	if (!test_bit(FLAG_IS_OUT, &desc->flags)) {
-		status = -EPERM;
-	} else if (status == 0) {
-		gpiod_set_value_cansleep(desc, value);
-		status = size;
-	}
+	if (!test_bit(FLAG_IS_OUT, &desc->flags))
+		return -EPERM;
+
+	if (status)
+		return status;
 
-	mutex_unlock(&data->mutex);
+	gpiod_set_value_cansleep(desc, value);
 
-	return status;
+	return size;
 }
 static DEVICE_ATTR_PREALLOC(value, S_IWUSR | S_IRUGO, value_show, value_store);
 
@@ -170,6 +166,10 @@ static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags)
 	unsigned long irq_flags;
 	int ret;
 
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return -ENODEV;
+
 	data->irq = gpiod_to_irq(desc);
 	if (data->irq < 0)
 		return -EIO;
@@ -179,12 +179,16 @@ static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags)
 		return -ENODEV;
 
 	irq_flags = IRQF_SHARED;
-	if (flags & GPIO_IRQF_TRIGGER_FALLING)
+	if (flags & GPIO_IRQF_TRIGGER_FALLING) {
 		irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
 			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
-	if (flags & GPIO_IRQF_TRIGGER_RISING)
+		set_bit(FLAG_EDGE_FALLING, &desc->flags);
+	}
+	if (flags & GPIO_IRQF_TRIGGER_RISING) {
 		irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
 			IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
+		set_bit(FLAG_EDGE_RISING, &desc->flags);
+	}
 
 	/*
 	 * FIXME: This should be done in the irq_request_resources callback
@@ -194,7 +198,7 @@ static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags)
 	 *        Remove this redundant call (along with the corresponding
 	 *        unlock) when those drivers have been fixed.
 	 */
-	ret = gpiochip_lock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc));
+	ret = gpiochip_lock_as_irq(guard.gc, gpio_chip_hwgpio(desc));
 	if (ret < 0)
 		goto err_put_kn;
 
@@ -208,8 +212,10 @@ static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags)
 	return 0;
 
 err_unlock:
-	gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc));
+	gpiochip_unlock_as_irq(guard.gc, gpio_chip_hwgpio(desc));
 err_put_kn:
+	clear_bit(FLAG_EDGE_RISING, &desc->flags);
+	clear_bit(FLAG_EDGE_FALLING, &desc->flags);
 	sysfs_put(data->value_kn);
 
 	return ret;
@@ -224,9 +230,15 @@ static void gpio_sysfs_free_irq(struct device *dev)
 	struct gpiod_data *data = dev_get_drvdata(dev);
 	struct gpio_desc *desc = data->desc;
 
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return;
+
 	data->irq_flags = 0;
 	free_irq(data->irq, data);
-	gpiochip_unlock_as_irq(desc->gdev->chip, gpio_chip_hwgpio(desc));
+	gpiochip_unlock_as_irq(guard.gc, gpio_chip_hwgpio(desc));
+	clear_bit(FLAG_EDGE_RISING, &desc->flags);
+	clear_bit(FLAG_EDGE_FALLING, &desc->flags);
 	sysfs_put(data->value_kn);
 }
 
@@ -243,11 +255,8 @@ static ssize_t edge_show(struct device *dev,
 	struct gpiod_data *data = dev_get_drvdata(dev);
 	int flags;
 
-	mutex_lock(&data->mutex);
-
-	flags = data->irq_flags;
-
-	mutex_unlock(&data->mutex);
+	scoped_guard(mutex, &data->mutex)
+		flags = data->irq_flags;
 
 	if (flags >= ARRAY_SIZE(trigger_names))
 		return 0;
@@ -266,26 +275,24 @@ static ssize_t edge_store(struct device *dev,
 	if (flags < 0)
 		return flags;
 
-	mutex_lock(&data->mutex);
+	guard(mutex)(&data->mutex);
 
-	if (flags == data->irq_flags) {
-		status = size;
-		goto out_unlock;
-	}
+	if (flags == data->irq_flags)
+		return size;
 
 	if (data->irq_flags)
 		gpio_sysfs_free_irq(dev);
 
-	if (flags) {
-		status = gpio_sysfs_request_irq(dev, flags);
-		if (!status)
-			status = size;
-	}
+	if (!flags)
+		return size;
+
+	status = gpio_sysfs_request_irq(dev, flags);
+	if (status)
+		return status;
 
-out_unlock:
-	mutex_unlock(&data->mutex);
+	gpiod_line_state_notify(data->desc, GPIO_V2_LINE_CHANGED_CONFIG);
 
-	return status;
+	return size;
 }
 static DEVICE_ATTR_RW(edge);
 
@@ -310,6 +317,8 @@ static int gpio_sysfs_set_active_low(struct device *dev, int value)
 		status = gpio_sysfs_request_irq(dev, flags);
 	}
 
+	gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
+
 	return status;
 }
 
@@ -320,11 +329,8 @@ static ssize_t active_low_show(struct device *dev,
 	struct gpio_desc *desc = data->desc;
 	int value;
 
-	mutex_lock(&data->mutex);
-
-	value = !!test_bit(FLAG_ACTIVE_LOW, &desc->flags);
-
-	mutex_unlock(&data->mutex);
+	scoped_guard(mutex, &data->mutex)
+		value = !!test_bit(FLAG_ACTIVE_LOW, &desc->flags);
 
 	return sysfs_emit(buf, "%d\n", value);
 }
@@ -340,13 +346,9 @@ static ssize_t active_low_store(struct device *dev,
 	if (status)
 		return status;
 
-	mutex_lock(&data->mutex);
-
-	status = gpio_sysfs_set_active_low(dev, value);
-
-	mutex_unlock(&data->mutex);
+	guard(mutex)(&data->mutex);
 
-	return status ? : size;
+	return gpio_sysfs_set_active_low(dev, value) ?: size;
 }
 static DEVICE_ATTR_RW(active_low);
 
@@ -400,27 +402,27 @@ static const struct attribute_group *gpio_groups[] = {
 static ssize_t base_show(struct device *dev,
 			       struct device_attribute *attr, char *buf)
 {
-	const struct gpio_chip *chip = dev_get_drvdata(dev);
+	const struct gpio_device *gdev = dev_get_drvdata(dev);
 
-	return sysfs_emit(buf, "%d\n", chip->base);
+	return sysfs_emit(buf, "%u\n", gdev->base);
 }
 static DEVICE_ATTR_RO(base);
 
 static ssize_t label_show(struct device *dev,
 			       struct device_attribute *attr, char *buf)
 {
-	const struct gpio_chip *chip = dev_get_drvdata(dev);
+	const struct gpio_device *gdev = dev_get_drvdata(dev);
 
-	return sysfs_emit(buf, "%s\n", chip->label ?: "");
+	return sysfs_emit(buf, "%s\n", gdev->label);
 }
 static DEVICE_ATTR_RO(label);
 
 static ssize_t ngpio_show(struct device *dev,
 			       struct device_attribute *attr, char *buf)
 {
-	const struct gpio_chip *chip = dev_get_drvdata(dev);
+	const struct gpio_device *gdev = dev_get_drvdata(dev);
 
-	return sysfs_emit(buf, "%u\n", chip->ngpio);
+	return sysfs_emit(buf, "%u\n", gdev->ngpio);
 }
 static DEVICE_ATTR_RO(ngpio);
 
@@ -443,24 +445,27 @@ static ssize_t export_store(const struct class *class,
 				const char *buf, size_t len)
 {
 	struct gpio_desc *desc;
-	struct gpio_chip *gc;
 	int status, offset;
 	long gpio;
 
 	status = kstrtol(buf, 0, &gpio);
-	if (status < 0)
-		goto done;
+	if (status)
+		return status;
 
 	desc = gpio_to_desc(gpio);
 	/* reject invalid GPIOs */
 	if (!desc) {
-		pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
+		pr_debug_ratelimited("%s: invalid GPIO %ld\n", __func__, gpio);
 		return -EINVAL;
 	}
-	gc = desc->gdev->chip;
+
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return -ENODEV;
+
 	offset = gpio_chip_hwgpio(desc);
-	if (!gpiochip_line_is_valid(gc, offset)) {
-		pr_warn("%s: GPIO %ld masked\n", __func__, gpio);
+	if (!gpiochip_line_is_valid(guard.gc, offset)) {
+		pr_debug_ratelimited("%s: GPIO %ld masked\n", __func__, gpio);
 		return -EINVAL;
 	}
 
@@ -480,10 +485,12 @@ static ssize_t export_store(const struct class *class,
 	}
 
 	status = gpiod_export(desc, true);
-	if (status < 0)
+	if (status < 0) {
 		gpiod_free(desc);
-	else
+	} else {
 		set_bit(FLAG_SYSFS, &desc->flags);
+		gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
+	}
 
 done:
 	if (status)
@@ -507,7 +514,7 @@ static ssize_t unexport_store(const struct class *class,
 	desc = gpio_to_desc(gpio);
 	/* reject bogus commands (gpiod_unexport() ignores them) */
 	if (!desc) {
-		pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
+		pr_debug_ratelimited("%s: invalid GPIO %ld\n", __func__, gpio);
 		return -EINVAL;
 	}
 
@@ -536,12 +543,11 @@ static struct attribute *gpio_class_attrs[] = {
 };
 ATTRIBUTE_GROUPS(gpio_class);
 
-static struct class gpio_class = {
+static const struct class gpio_class = {
 	.name =		"gpio",
-	.class_groups = gpio_class_groups,
+	.class_groups =	gpio_class_groups,
 };
 
-
 /**
  * gpiod_export - export a GPIO through sysfs
  * @desc: GPIO to make available, already requested
@@ -555,17 +561,15 @@ static struct class gpio_class = {
  * will see "direction" sysfs attribute which may be used to change
  * the gpio's direction.  A "value" attribute will always be provided.
  *
- * Returns zero on success, else an error.
+ * Returns:
+ * 0 on success, or negative errno on failure.
  */
 int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
 {
-	const char *ioname = NULL;
 	struct gpio_device *gdev;
 	struct gpiod_data *data;
-	struct gpio_chip *chip;
-	unsigned long flags;
 	struct device *dev;
-	int status, offset;
+	int status;
 
 	/* can't export until sysfs is available ... */
 	if (!class_is_registered(&gpio_class)) {
@@ -578,64 +582,56 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
 		return -EINVAL;
 	}
 
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return -ENODEV;
+
+	if (test_and_set_bit(FLAG_EXPORT, &desc->flags))
+		return -EPERM;
+
 	gdev = desc->gdev;
-	chip = gdev->chip;
 
-	mutex_lock(&sysfs_lock);
+	guard(mutex)(&sysfs_lock);
 
 	/* check if chip is being removed */
-	if (!chip || !gdev->mockdev) {
+	if (!gdev->mockdev) {
 		status = -ENODEV;
-		goto err_unlock;
+		goto err_clear_bit;
 	}
 
-	spin_lock_irqsave(&gpio_lock, flags);
-	if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
-	     test_bit(FLAG_EXPORT, &desc->flags)) {
-		spin_unlock_irqrestore(&gpio_lock, flags);
-		gpiod_dbg(desc, "%s: unavailable (requested=%d, exported=%d)\n",
-				__func__,
-				test_bit(FLAG_REQUESTED, &desc->flags),
-				test_bit(FLAG_EXPORT, &desc->flags));
+	if (!test_bit(FLAG_REQUESTED, &desc->flags)) {
+		gpiod_dbg(desc, "%s: unavailable (not requested)\n", __func__);
 		status = -EPERM;
-		goto err_unlock;
+		goto err_clear_bit;
 	}
-	spin_unlock_irqrestore(&gpio_lock, flags);
 
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data) {
 		status = -ENOMEM;
-		goto err_unlock;
+		goto err_clear_bit;
 	}
 
 	data->desc = desc;
 	mutex_init(&data->mutex);
-	if (chip->direction_input && chip->direction_output)
+	if (guard.gc->direction_input && guard.gc->direction_output)
 		data->direction_can_change = direction_may_change;
 	else
 		data->direction_can_change = false;
 
-	offset = gpio_chip_hwgpio(desc);
-	if (chip->names && chip->names[offset])
-		ioname = chip->names[offset];
-
 	dev = device_create_with_groups(&gpio_class, &gdev->dev,
 					MKDEV(0, 0), data, gpio_groups,
-					ioname ? ioname : "gpio%u",
-					desc_to_gpio(desc));
+					"gpio%u", desc_to_gpio(desc));
 	if (IS_ERR(dev)) {
 		status = PTR_ERR(dev);
 		goto err_free_data;
 	}
 
-	set_bit(FLAG_EXPORT, &desc->flags);
-	mutex_unlock(&sysfs_lock);
 	return 0;
 
 err_free_data:
 	kfree(data);
-err_unlock:
-	mutex_unlock(&sysfs_lock);
+err_clear_bit:
+	clear_bit(FLAG_EXPORT, &desc->flags);
 	gpiod_dbg(desc, "%s: status %d\n", __func__, status);
 	return status;
 }
@@ -657,7 +653,8 @@ static int match_export(struct device *dev, const void *desc)
  * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
  * node. Caller is responsible for unlinking.
  *
- * Returns zero on success, else an error.
+ * Returns:
+ * 0 on success, or negative errno on failure.
  */
 int gpiod_export_link(struct device *dev, const char *name,
 		      struct gpio_desc *desc)
@@ -697,42 +694,34 @@ void gpiod_unexport(struct gpio_desc *desc)
 		return;
 	}
 
-	mutex_lock(&sysfs_lock);
-
-	if (!test_bit(FLAG_EXPORT, &desc->flags))
-		goto err_unlock;
-
-	dev = class_find_device(&gpio_class, NULL, desc, match_export);
-	if (!dev)
-		goto err_unlock;
-
-	data = dev_get_drvdata(dev);
-
-	clear_bit(FLAG_EXPORT, &desc->flags);
+	scoped_guard(mutex, &sysfs_lock) {
+		if (!test_bit(FLAG_EXPORT, &desc->flags))
+			return;
 
-	device_unregister(dev);
+		dev = class_find_device(&gpio_class, NULL, desc, match_export);
+		if (!dev)
+			return;
 
-	/*
-	 * Release irq after deregistration to prevent race with edge_store.
-	 */
-	if (data->irq_flags)
-		gpio_sysfs_free_irq(dev);
+		data = dev_get_drvdata(dev);
+		clear_bit(FLAG_EXPORT, &desc->flags);
+		device_unregister(dev);
 
-	mutex_unlock(&sysfs_lock);
+		/*
+		 * Release irq after deregistration to prevent race with
+		 * edge_store.
+		 */
+		if (data->irq_flags)
+			gpio_sysfs_free_irq(dev);
+	}
 
 	put_device(dev);
 	kfree(data);
-
-	return;
-
-err_unlock:
-	mutex_unlock(&sysfs_lock);
 }
 EXPORT_SYMBOL_GPL(gpiod_unexport);
 
 int gpiochip_sysfs_register(struct gpio_device *gdev)
 {
-	struct gpio_chip *chip = gdev->chip;
+	struct gpio_chip *chip;
 	struct device *parent;
 	struct device *dev;
 
@@ -745,6 +734,12 @@ int gpiochip_sysfs_register(struct gpio_device *gdev)
 	if (!class_is_registered(&gpio_class))
 		return 0;
 
+	guard(srcu)(&gdev->srcu);
+
+	chip = srcu_dereference(gdev->chip, &gdev->srcu);
+	if (!chip)
+		return -ENODEV;
+
 	/*
 	 * For sysfs backward compatibility we need to preserve this
 	 * preferred parenting to the gpio_chip parent field, if set.
@@ -755,15 +750,14 @@ int gpiochip_sysfs_register(struct gpio_device *gdev)
 		parent = &gdev->dev;
 
 	/* use chip->base for the ID; it's already known to be unique */
-	dev = device_create_with_groups(&gpio_class, parent, MKDEV(0, 0), chip,
+	dev = device_create_with_groups(&gpio_class, parent, MKDEV(0, 0), gdev,
 					gpiochip_groups, GPIOCHIP_NAME "%d",
 					chip->base);
 	if (IS_ERR(dev))
 		return PTR_ERR(dev);
 
-	mutex_lock(&sysfs_lock);
+	guard(mutex)(&sysfs_lock);
 	gdev->mockdev = dev;
-	mutex_unlock(&sysfs_lock);
 
 	return 0;
 }
@@ -771,17 +765,23 @@ int gpiochip_sysfs_register(struct gpio_device *gdev)
 void gpiochip_sysfs_unregister(struct gpio_device *gdev)
 {
 	struct gpio_desc *desc;
-	struct gpio_chip *chip = gdev->chip;
+	struct gpio_chip *chip;
 
-	if (!gdev->mockdev)
-		return;
+	scoped_guard(mutex, &sysfs_lock) {
+		if (!gdev->mockdev)
+			return;
 
-	device_unregister(gdev->mockdev);
+		device_unregister(gdev->mockdev);
 
-	/* prevent further gpiod exports */
-	mutex_lock(&sysfs_lock);
-	gdev->mockdev = NULL;
-	mutex_unlock(&sysfs_lock);
+		/* prevent further gpiod exports */
+		gdev->mockdev = NULL;
+	}
+
+	guard(srcu)(&gdev->srcu);
+
+	chip = srcu_dereference(gdev->chip, &gdev->srcu);
+	if (!chip)
+		return;
 
 	/* unregister gpiod class devices owned by sysfs */
 	for_each_gpio_desc_with_flag(chip, desc, FLAG_SYSFS) {
@@ -790,11 +790,29 @@ void gpiochip_sysfs_unregister(struct gpio_device *gdev)
 	}
 }
 
+/*
+ * We're not really looking for a device - we just want to iterate over the
+ * list and call this callback for each GPIO device. This is why this function
+ * always returns 0.
+ */
+static int gpiofind_sysfs_register(struct gpio_chip *gc, const void *data)
+{
+	struct gpio_device *gdev = gc->gpiodev;
+	int ret;
+
+	if (gdev->mockdev)
+		return 0;
+
+	ret = gpiochip_sysfs_register(gdev);
+	if (ret)
+		chip_err(gc, "failed to register the sysfs entry: %d\n", ret);
+
+	return 0;
+}
+
 static int __init gpiolib_sysfs_init(void)
 {
-	int		status;
-	unsigned long	flags;
-	struct gpio_device *gdev;
+	int status;
 
 	status = class_register(&gpio_class);
 	if (status < 0)
@@ -806,26 +824,8 @@ static int __init gpiolib_sysfs_init(void)
 	 * We run before arch_initcall() so chip->dev nodes can have
 	 * registered, and so arch_initcall() can always gpiod_export().
 	 */
-	spin_lock_irqsave(&gpio_lock, flags);
-	list_for_each_entry(gdev, &gpio_devices, list) {
-		if (gdev->mockdev)
-			continue;
+	(void)gpio_device_find(NULL, gpiofind_sysfs_register);
 
-		/*
-		 * TODO we yield gpio_lock here because
-		 * gpiochip_sysfs_register() acquires a mutex. This is unsafe
-		 * and needs to be fixed.
-		 *
-		 * Also it would be nice to use gpio_device_find() here so we
-		 * can keep gpio_chips local to gpiolib.c, but the yield of
-		 * gpio_lock prevents us from doing this.
-		 */
-		spin_unlock_irqrestore(&gpio_lock, flags);
-		status = gpiochip_sysfs_register(gdev);
-		spin_lock_irqsave(&gpio_lock, flags);
-	}
-	spin_unlock_irqrestore(&gpio_lock, flags);
-
-	return status;
+	return 0;
 }
 postcore_initcall(gpiolib_sysfs_init);