A slew of fixes dealing with some irritating bugs (non-regressions)

that have been around forever in the GPIO subsystem, most of them
 also tagged for stable:
 
 - A large slew of fixes from Johan Hovold who is finally testing and
   reviewing the removal path of the GPIO drivers.
 
 - Fix of_get_named_gpiod_flags() so it works as expected.
 
 - Fix an IRQ handling bug in the crystalcove driver.
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Merge tag 'gpio-v3.19-4' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

Pull GPIO fixes from Linus Walleij:
 "Here is a set of fixes that mainly appeared when Johan Hovold started
  exercising the removal path of the GPIO library, dealing with
  hotplugging of GPIO controllers. Details from tag:

  A slew of fixes dealing with some irritating bugs (non-regressions)
  that have been around forever in the GPIO subsystem, most of them also
  tagged for stable:

   - A large slew of fixes from Johan Hovold who is finally testing and
     reviewing the removal path of the GPIO drivers.

   - Fix of_get_named_gpiod_flags() so it works as expected.

   - Fix an IRQ handling bug in the crystalcove driver"

* tag 'gpio-v3.19-4' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpiolib: of: Correct error handling in of_get_named_gpiod_flags
  gpio: sysfs: fix gpio attribute-creation race
  gpio: sysfs: fix gpio device-attribute leak
  gpio: sysfs: fix gpio-chip device-attribute leak
  gpio: unregister gpiochip device before removing it
  gpio: fix sleep-while-atomic in gpiochip_remove
  gpio: fix memory leak and sleep-while-atomic
  gpio: clean up gpiochip_add error handling
  gpio: fix gpio-chip list corruption
  gpio: fix memory and reference leaks in gpiochip_add error path
  gpio: crystalcove: use handle_nested_irq

drivers/gpio/gpio-crystalcove.c

@@ -272,7 +272,7 @@ static irqreturn_t crystalcove_gpio_irq_handler(int irq, void *data)
 	for (gpio = 0; gpio < CRYSTALCOVE_GPIO_NUM; gpio++) {
 		if (pending & BIT(gpio)) {
 			virq = irq_find_mapping(cg->chip.irqdomain, gpio);
-			generic_handle_irq(virq);
+			handle_nested_irq(virq);
 		}
 	}
 

drivers/gpio/gpiolib-of.c

@@ -45,8 +45,14 @@ static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
 		return false;
 
 	ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
-	if (ret < 0)
-		return false;
+	if (ret < 0) {
+		/* We've found the gpio chip, but the translation failed.
+		 * Return true to stop looking and return the translation
+		 * error via out_gpio
+		 */
+		gg_data->out_gpio = ERR_PTR(ret);
+		return true;
+	 }
 
 	gg_data->out_gpio = gpiochip_get_desc(gc, ret);
 	return true;

drivers/gpio/gpiolib-sysfs.c

@@ -128,7 +128,7 @@ static ssize_t gpio_value_store(struct device *dev,
 	return status;
 }
 
-static const DEVICE_ATTR(value, 0644,
+static DEVICE_ATTR(value, 0644,
 		gpio_value_show, gpio_value_store);
 
 static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
@@ -353,17 +353,46 @@ static ssize_t gpio_active_low_store(struct device *dev,
 	return status ? : size;
 }
 
-static const DEVICE_ATTR(active_low, 0644,
+static DEVICE_ATTR(active_low, 0644,
 		gpio_active_low_show, gpio_active_low_store);
 
-static const struct attribute *gpio_attrs[] = {
+static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr,
+			       int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct gpio_desc *desc = dev_get_drvdata(dev);
+	umode_t mode = attr->mode;
+	bool show_direction = test_bit(FLAG_SYSFS_DIR, &desc->flags);
+
+	if (attr == &dev_attr_direction.attr) {
+		if (!show_direction)
+			mode = 0;
+	} else if (attr == &dev_attr_edge.attr) {
+		if (gpiod_to_irq(desc) < 0)
+			mode = 0;
+		if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags))
+			mode = 0;
+	}
+
+	return mode;
+}
+
+static struct attribute *gpio_attrs[] = {
+	&dev_attr_direction.attr,
+	&dev_attr_edge.attr,
 	&dev_attr_value.attr,
 	&dev_attr_active_low.attr,
 	NULL,
 };
 
-static const struct attribute_group gpio_attr_group = {
-	.attrs = (struct attribute **) gpio_attrs,
+static const struct attribute_group gpio_group = {
+	.attrs = gpio_attrs,
+	.is_visible = gpio_is_visible,
+};
+
+static const struct attribute_group *gpio_groups[] = {
+	&gpio_group,
+	NULL
 };
 
 /*
@@ -400,16 +429,13 @@ static ssize_t chip_ngpio_show(struct device *dev,
 }
 static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
 
-static const struct attribute *gpiochip_attrs[] = {
+static struct attribute *gpiochip_attrs[] = {
 	&dev_attr_base.attr,
 	&dev_attr_label.attr,
 	&dev_attr_ngpio.attr,
 	NULL,
 };
-
-static const struct attribute_group gpiochip_attr_group = {
-	.attrs = (struct attribute **) gpiochip_attrs,
-};
+ATTRIBUTE_GROUPS(gpiochip);
 
 /*
  * /sys/class/gpio/export ... write-only
@@ -556,45 +582,30 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
 		goto fail_unlock;
 	}
 
-	if (!desc->chip->direction_input || !desc->chip->direction_output)
-		direction_may_change = false;
+	if (desc->chip->direction_input && desc->chip->direction_output &&
+			direction_may_change) {
+		set_bit(FLAG_SYSFS_DIR, &desc->flags);
+	}
+
 	spin_unlock_irqrestore(&gpio_lock, flags);
 
 	offset = gpio_chip_hwgpio(desc);
 	if (desc->chip->names && desc->chip->names[offset])
 		ioname = desc->chip->names[offset];
 
-	dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
-			    desc, ioname ? ioname : "gpio%u",
-			    desc_to_gpio(desc));
+	dev = device_create_with_groups(&gpio_class, desc->chip->dev,
+					MKDEV(0, 0), desc, gpio_groups,
+					ioname ? ioname : "gpio%u",
+					desc_to_gpio(desc));
 	if (IS_ERR(dev)) {
 		status = PTR_ERR(dev);
 		goto fail_unlock;
 	}
 
-	status = sysfs_create_group(&dev->kobj, &gpio_attr_group);
-	if (status)
-		goto fail_unregister_device;
-
-	if (direction_may_change) {
-		status = device_create_file(dev, &dev_attr_direction);
-		if (status)
-			goto fail_unregister_device;
-	}
-
-	if (gpiod_to_irq(desc) >= 0 && (direction_may_change ||
-				       !test_bit(FLAG_IS_OUT, &desc->flags))) {
-		status = device_create_file(dev, &dev_attr_edge);
-		if (status)
-			goto fail_unregister_device;
-	}
-
 	set_bit(FLAG_EXPORT, &desc->flags);
 	mutex_unlock(&sysfs_lock);
 	return 0;
 
-fail_unregister_device:
-	device_unregister(dev);
 fail_unlock:
 	mutex_unlock(&sysfs_lock);
 	gpiod_dbg(desc, "%s: status %d\n", __func__, status);
@@ -718,6 +729,7 @@ void gpiod_unexport(struct gpio_desc *desc)
 		dev = class_find_device(&gpio_class, NULL, desc, match_export);
 		if (dev) {
 			gpio_setup_irq(desc, dev, 0);
+			clear_bit(FLAG_SYSFS_DIR, &desc->flags);
 			clear_bit(FLAG_EXPORT, &desc->flags);
 		} else
 			status = -ENODEV;
@@ -750,13 +762,13 @@ int gpiochip_export(struct gpio_chip *chip)
 
 	/* use chip->base for the ID; it's already known to be unique */
 	mutex_lock(&sysfs_lock);
-	dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
-				"gpiochip%d", chip->base);
-	if (!IS_ERR(dev)) {
-		status = sysfs_create_group(&dev->kobj,
-				&gpiochip_attr_group);
-	} else
+	dev = device_create_with_groups(&gpio_class, chip->dev, MKDEV(0, 0),
+					chip, gpiochip_groups,
+					"gpiochip%d", chip->base);
+	if (IS_ERR(dev))
 		status = PTR_ERR(dev);
+	else
+		status = 0;
 	chip->exported = (status == 0);
 	mutex_unlock(&sysfs_lock);
 

drivers/gpio/gpiolib.c

@@ -248,29 +248,30 @@ int gpiochip_add(struct gpio_chip *chip)
 		base = gpiochip_find_base(chip->ngpio);
 		if (base < 0) {
 			status = base;
-			goto unlock;
+			spin_unlock_irqrestore(&gpio_lock, flags);
+			goto err_free_descs;
 		}
 		chip->base = base;
 	}
 
 	status = gpiochip_add_to_list(chip);
+	if (status) {
+		spin_unlock_irqrestore(&gpio_lock, flags);
+		goto err_free_descs;
+	}
 
-	if (status == 0) {
-		for (id = 0; id < chip->ngpio; id++) {
-			struct gpio_desc *desc = &descs[id];
-			desc->chip = chip;
+	for (id = 0; id < chip->ngpio; id++) {
+		struct gpio_desc *desc = &descs[id];
 
-			/* REVISIT:  most hardware initializes GPIOs as
-			 * inputs (often with pullups enabled) so power
-			 * usage is minimized.  Linux code should set the
-			 * gpio direction first thing; but until it does,
-			 * and in case chip->get_direction is not set,
-			 * we may expose the wrong direction in sysfs.
-			 */
-			desc->flags = !chip->direction_input
-				? (1 << FLAG_IS_OUT)
-				: 0;
-		}
+		desc->chip = chip;
+
+		/* REVISIT: most hardware initializes GPIOs as inputs (often
+		 * with pullups enabled) so power usage is minimized. Linux
+		 * code should set the gpio direction first thing; but until
+		 * it does, and in case chip->get_direction is not set, we may
+		 * expose the wrong direction in sysfs.
+		 */
+		desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
 	}
 
 	chip->desc = descs;
@@ -284,12 +285,9 @@ int gpiochip_add(struct gpio_chip *chip)
 	of_gpiochip_add(chip);
 	acpi_gpiochip_add(chip);
 
-	if (status)
-		goto fail;
-
 	status = gpiochip_export(chip);
 	if (status)
-		goto fail;
+		goto err_remove_chip;
 
 	pr_debug("%s: registered GPIOs %d to %d on device: %s\n", __func__,
 		chip->base, chip->base + chip->ngpio - 1,
@@ -297,11 +295,15 @@ int gpiochip_add(struct gpio_chip *chip)
 
 	return 0;
 
-unlock:
+err_remove_chip:
+	acpi_gpiochip_remove(chip);
+	of_gpiochip_remove(chip);
+	spin_lock_irqsave(&gpio_lock, flags);
+	list_del(&chip->list);
 	spin_unlock_irqrestore(&gpio_lock, flags);
-fail:
-	kfree(descs);
 	chip->desc = NULL;
+err_free_descs:
+	kfree(descs);
 
 	/* failures here can mean systems won't boot... */
 	pr_err("%s: GPIOs %d..%d (%s) failed to register\n", __func__,
@@ -325,14 +327,15 @@ void gpiochip_remove(struct gpio_chip *chip)
 	unsigned long	flags;
 	unsigned	id;
 
-	acpi_gpiochip_remove(chip);
-
-	spin_lock_irqsave(&gpio_lock, flags);
+	gpiochip_unexport(chip);
 
 	gpiochip_irqchip_remove(chip);
+
+	acpi_gpiochip_remove(chip);
 	gpiochip_remove_pin_ranges(chip);
 	of_gpiochip_remove(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");
@@ -342,7 +345,6 @@ void gpiochip_remove(struct gpio_chip *chip)
 
 	list_del(&chip->list);
 	spin_unlock_irqrestore(&gpio_lock, flags);
-	gpiochip_unexport(chip);
 
 	kfree(chip->desc);
 	chip->desc = NULL;

drivers/gpio/gpiolib.h

@@ -77,6 +77,7 @@ struct gpio_desc {
 #define FLAG_OPEN_DRAIN	7	/* Gpio is open drain type */
 #define FLAG_OPEN_SOURCE 8	/* Gpio is open source type */
 #define FLAG_USED_AS_IRQ 9	/* GPIO is connected to an IRQ */
+#define FLAG_SYSFS_DIR	10	/* show sysfs direction attribute */
 
 #define ID_SHIFT	16	/* add new flags before this one */