[PATCH v3] gpio: sim: simplify code with cleanup helpers

[PATCH v3] gpio: sim: simplify code with cleanup helpers

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Use macros defined in linux/cleanup.h to automate resource lifetime
control in gpio-sim.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
v2 -> v3:
- use the non-scoped guard() in two more places where we can return the
  return value of snprintf() directly
- DON'T die on the hill of
  no-line-wrapping-for-the-price-of-more-temp-variables Andy :)

v1 -> v2:
- reorder code to return earlier from functions whenever possible, for
  instance when the last line is just returning a value from snprintf(),
  this saves us int ret; local variables
- tweak the commit message

 drivers/gpio/gpio-sim.c | 254 ++++++++++++++--------------------------
 1 file changed, 85 insertions(+), 169 deletions(-)

diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index 0177b41e0d72..bb8fcf2a794c 100644
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -8,6 +8,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/bitmap.h>
+#include <linux/cleanup.h>
 #include <linux/completion.h>
 #include <linux/configfs.h>
 #include <linux/device.h>
@@ -68,7 +69,7 @@ static int gpio_sim_apply_pull(struct gpio_sim_chip *chip,
 	gc = &chip->gc;
 	desc = &gc->gpiodev->descs[offset];
 
-	mutex_lock(&chip->lock);
+	guard(mutex)(&chip->lock);
 
 	if (test_bit(FLAG_REQUESTED, &desc->flags) &&
 	    !test_bit(FLAG_IS_OUT, &desc->flags)) {
@@ -104,29 +105,24 @@ static int gpio_sim_apply_pull(struct gpio_sim_chip *chip,
 
 set_pull:
 	__assign_bit(offset, chip->pull_map, value);
-	mutex_unlock(&chip->lock);
 	return 0;
 }
 
 static int gpio_sim_get(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
-	int ret;
 
-	mutex_lock(&chip->lock);
-	ret = !!test_bit(offset, chip->value_map);
-	mutex_unlock(&chip->lock);
+	guard(mutex)(&chip->lock);
 
-	return ret;
+	return !!test_bit(offset, chip->value_map);
 }
 
 static void gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value)
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
-	mutex_lock(&chip->lock);
-	__assign_bit(offset, chip->value_map, value);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		__assign_bit(offset, chip->value_map, value);
 }
 
 static int gpio_sim_get_multiple(struct gpio_chip *gc,
@@ -134,9 +130,8 @@ static int gpio_sim_get_multiple(struct gpio_chip *gc,
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
-	mutex_lock(&chip->lock);
-	bitmap_replace(bits, bits, chip->value_map, mask, gc->ngpio);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		bitmap_replace(bits, bits, chip->value_map, mask, gc->ngpio);
 
 	return 0;
 }
@@ -146,9 +141,9 @@ static void gpio_sim_set_multiple(struct gpio_chip *gc,
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
-	mutex_lock(&chip->lock);
-	bitmap_replace(chip->value_map, chip->value_map, bits, mask, gc->ngpio);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		bitmap_replace(chip->value_map, chip->value_map, bits, mask,
+			       gc->ngpio);
 }
 
 static int gpio_sim_direction_output(struct gpio_chip *gc,
@@ -156,10 +151,10 @@ static int gpio_sim_direction_output(struct gpio_chip *gc,
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
-	mutex_lock(&chip->lock);
-	__clear_bit(offset, chip->direction_map);
-	__assign_bit(offset, chip->value_map, value);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock) {
+		__clear_bit(offset, chip->direction_map);
+		__assign_bit(offset, chip->value_map, value);
+	}
 
 	return 0;
 }
@@ -168,9 +163,8 @@ static int gpio_sim_direction_input(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
-	mutex_lock(&chip->lock);
-	__set_bit(offset, chip->direction_map);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		__set_bit(offset, chip->direction_map);
 
 	return 0;
 }
@@ -180,9 +174,8 @@ static int gpio_sim_get_direction(struct gpio_chip *gc, unsigned int offset)
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 	int direction;
 
-	mutex_lock(&chip->lock);
-	direction = !!test_bit(offset, chip->direction_map);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		direction = !!test_bit(offset, chip->direction_map);
 
 	return direction ? GPIO_LINE_DIRECTION_IN : GPIO_LINE_DIRECTION_OUT;
 }
@@ -215,9 +208,9 @@ static void gpio_sim_free(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
 
-	mutex_lock(&chip->lock);
-	__assign_bit(offset, chip->value_map, !!test_bit(offset, chip->pull_map));
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		__assign_bit(offset, chip->value_map,
+			     !!test_bit(offset, chip->pull_map));
 }
 
 static ssize_t gpio_sim_sysfs_val_show(struct device *dev,
@@ -227,9 +220,8 @@ static ssize_t gpio_sim_sysfs_val_show(struct device *dev,
 	struct gpio_sim_chip *chip = dev_get_drvdata(dev);
 	int val;
 
-	mutex_lock(&chip->lock);
-	val = !!test_bit(line_attr->offset, chip->value_map);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		val = !!test_bit(line_attr->offset, chip->value_map);
 
 	return sysfs_emit(buf, "%d\n", val);
 }
@@ -258,9 +250,8 @@ static ssize_t gpio_sim_sysfs_pull_show(struct device *dev,
 	struct gpio_sim_chip *chip = dev_get_drvdata(dev);
 	int pull;
 
-	mutex_lock(&chip->lock);
-	pull = !!test_bit(line_attr->offset, chip->pull_map);
-	mutex_unlock(&chip->lock);
+	scoped_guard(mutex, &chip->lock)
+		pull = !!test_bit(line_attr->offset, chip->pull_map);
 
 	return sysfs_emit(buf, "%s\n", gpio_sim_sysfs_pull_strings[pull]);
 }
@@ -659,17 +650,14 @@ static ssize_t gpio_sim_device_config_dev_name_show(struct config_item *item,
 {
 	struct gpio_sim_device *dev = to_gpio_sim_device(item);
 	struct platform_device *pdev;
-	int ret;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
+
 	pdev = dev->pdev;
 	if (pdev)
-		ret = sprintf(page, "%s\n", dev_name(&pdev->dev));
-	else
-		ret = sprintf(page, "gpio-sim.%d\n", dev->id);
-	mutex_unlock(&dev->lock);
+		return sprintf(page, "%s\n", dev_name(&pdev->dev));
 
-	return ret;
+	return sprintf(page, "gpio-sim.%d\n", dev->id);
 }
 
 CONFIGFS_ATTR_RO(gpio_sim_device_config_, dev_name);
@@ -680,9 +668,8 @@ gpio_sim_device_config_live_show(struct config_item *item, char *page)
 	struct gpio_sim_device *dev = to_gpio_sim_device(item);
 	bool live;
 
-	mutex_lock(&dev->lock);
-	live = gpio_sim_device_is_live_unlocked(dev);
-	mutex_unlock(&dev->lock);
+	scoped_guard(mutex, &dev->lock)
+		live = gpio_sim_device_is_live_unlocked(dev);
 
 	return sprintf(page, "%c\n", live ? '1' : '0');
 }
@@ -837,8 +824,7 @@ gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
 {
 	struct property_entry properties[GPIO_SIM_PROP_MAX];
 	unsigned int prop_idx = 0, line_names_size = 0;
-	struct fwnode_handle *swnode;
-	char **line_names;
+	char **line_names __free(kfree) = NULL;
 
 	memset(properties, 0, sizeof(properties));
 
@@ -857,9 +843,7 @@ gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
 						"gpio-line-names",
 						line_names, line_names_size);
 
-	swnode = fwnode_create_software_node(properties, parent);
-	kfree(line_names);
-	return swnode;
+	return fwnode_create_software_node(properties, parent);
 }
 
 static void gpio_sim_remove_swnode_recursive(struct fwnode_handle *swnode)
@@ -984,7 +968,7 @@ gpio_sim_device_config_live_store(struct config_item *item,
 	if (ret)
 		return ret;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
 	if (live == gpio_sim_device_is_live_unlocked(dev))
 		ret = -EPERM;
@@ -993,8 +977,6 @@ gpio_sim_device_config_live_store(struct config_item *item,
 	else
 		gpio_sim_device_deactivate_unlocked(dev);
 
-	mutex_unlock(&dev->lock);
-
 	return ret ?: count;
 }
 
@@ -1031,17 +1013,14 @@ static ssize_t gpio_sim_bank_config_chip_name_show(struct config_item *item,
 	struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
 	struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
 	struct gpio_sim_chip_name_ctx ctx = { bank->swnode, page };
-	int ret;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
+
 	if (gpio_sim_device_is_live_unlocked(dev))
-		ret = device_for_each_child(&dev->pdev->dev, &ctx,
-					    gpio_sim_emit_chip_name);
-	else
-		ret = sprintf(page, "none\n");
-	mutex_unlock(&dev->lock);
+		return device_for_each_child(&dev->pdev->dev, &ctx,
+					     gpio_sim_emit_chip_name);
 
-	return ret;
+	return sprintf(page, "none\n");
 }
 
 CONFIGFS_ATTR_RO(gpio_sim_bank_config_, chip_name);
@@ -1051,13 +1030,10 @@ gpio_sim_bank_config_label_show(struct config_item *item, char *page)
 {
 	struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
 	struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
-	int ret;
 
-	mutex_lock(&dev->lock);
-	ret = sprintf(page, "%s\n", bank->label ?: "");
-	mutex_unlock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	return ret;
+	return sprintf(page, "%s\n", bank->label ?: "");
 }
 
 static ssize_t gpio_sim_bank_config_label_store(struct config_item *item,
@@ -1067,23 +1043,18 @@ static ssize_t gpio_sim_bank_config_label_store(struct config_item *item,
 	struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
 	char *trimmed;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return -EBUSY;
-	}
 
 	trimmed = gpio_sim_strdup_trimmed(page, count);
-	if (!trimmed) {
-		mutex_unlock(&dev->lock);
+	if (!trimmed)
 		return -ENOMEM;
-	}
 
 	kfree(bank->label);
 	bank->label = trimmed;
 
-	mutex_unlock(&dev->lock);
 	return count;
 }
 
@@ -1094,13 +1065,10 @@ gpio_sim_bank_config_num_lines_show(struct config_item *item, char *page)
 {
 	struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
 	struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
-	int ret;
 
-	mutex_lock(&dev->lock);
-	ret = sprintf(page, "%u\n", bank->num_lines);
-	mutex_unlock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	return ret;
+	return sprintf(page, "%u\n", bank->num_lines);
 }
 
 static ssize_t
@@ -1119,16 +1087,13 @@ gpio_sim_bank_config_num_lines_store(struct config_item *item,
 	if (num_lines == 0)
 		return -EINVAL;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return -EBUSY;
-	}
 
 	bank->num_lines = num_lines;
 
-	mutex_unlock(&dev->lock);
 	return count;
 }
 
@@ -1146,13 +1111,10 @@ gpio_sim_line_config_name_show(struct config_item *item, char *page)
 {
 	struct gpio_sim_line *line = to_gpio_sim_line(item);
 	struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
-	int ret;
 
-	mutex_lock(&dev->lock);
-	ret = sprintf(page, "%s\n", line->name ?: "");
-	mutex_unlock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	return ret;
+	return sprintf(page, "%s\n", line->name ?: "");
 }
 
 static ssize_t gpio_sim_line_config_name_store(struct config_item *item,
@@ -1162,24 +1124,18 @@ static ssize_t gpio_sim_line_config_name_store(struct config_item *item,
 	struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
 	char *trimmed;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return -EBUSY;
-	}
 
 	trimmed = gpio_sim_strdup_trimmed(page, count);
-	if (!trimmed) {
-		mutex_unlock(&dev->lock);
+	if (!trimmed)
 		return -ENOMEM;
-	}
 
 	kfree(line->name);
 	line->name = trimmed;
 
-	mutex_unlock(&dev->lock);
-
 	return count;
 }
 
@@ -1195,13 +1151,10 @@ static ssize_t gpio_sim_hog_config_name_show(struct config_item *item,
 {
 	struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
 	struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
-	int ret;
 
-	mutex_lock(&dev->lock);
-	ret = sprintf(page, "%s\n", hog->name ?: "");
-	mutex_unlock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	return ret;
+	return sprintf(page, "%s\n", hog->name ?: "");
 }
 
 static ssize_t gpio_sim_hog_config_name_store(struct config_item *item,
@@ -1211,24 +1164,18 @@ static ssize_t gpio_sim_hog_config_name_store(struct config_item *item,
 	struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
 	char *trimmed;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return -EBUSY;
-	}
 
 	trimmed = gpio_sim_strdup_trimmed(page, count);
-	if (!trimmed) {
-		mutex_unlock(&dev->lock);
+	if (!trimmed)
 		return -ENOMEM;
-	}
 
 	kfree(hog->name);
 	hog->name = trimmed;
 
-	mutex_unlock(&dev->lock);
-
 	return count;
 }
 
@@ -1242,9 +1189,8 @@ static ssize_t gpio_sim_hog_config_direction_show(struct config_item *item,
 	char *repr;
 	int dir;
 
-	mutex_lock(&dev->lock);
-	dir = hog->dir;
-	mutex_unlock(&dev->lock);
+	scoped_guard(mutex, &dev->lock)
+		dir = hog->dir;
 
 	switch (dir) {
 	case GPIOD_IN:
@@ -1273,12 +1219,10 @@ gpio_sim_hog_config_direction_store(struct config_item *item,
 	struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
 	int dir;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return -EBUSY;
-	}
 
 	if (sysfs_streq(page, "input"))
 		dir = GPIOD_IN;
@@ -1287,17 +1231,10 @@ gpio_sim_hog_config_direction_store(struct config_item *item,
 	else if (sysfs_streq(page, "output-low"))
 		dir = GPIOD_OUT_LOW;
 	else
-		dir = -EINVAL;
-
-	if (dir < 0) {
-		mutex_unlock(&dev->lock);
-		return dir;
-	}
+		return -EINVAL;
 
 	hog->dir = dir;
 
-	mutex_unlock(&dev->lock);
-
 	return count;
 }
 
@@ -1315,9 +1252,8 @@ static void gpio_sim_hog_config_item_release(struct config_item *item)
 	struct gpio_sim_line *line = hog->parent;
 	struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
 
-	mutex_lock(&dev->lock);
-	line->hog = NULL;
-	mutex_unlock(&dev->lock);
+	scoped_guard(mutex, &dev->lock)
+		line->hog = NULL;
 
 	kfree(hog->name);
 	kfree(hog);
@@ -1343,13 +1279,11 @@ gpio_sim_line_config_make_hog_item(struct config_group *group, const char *name)
 	if (strcmp(name, "hog") != 0)
 		return ERR_PTR(-EINVAL);
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
 	hog = kzalloc(sizeof(*hog), GFP_KERNEL);
-	if (!hog) {
-		mutex_unlock(&dev->lock);
+	if (!hog)
 		return ERR_PTR(-ENOMEM);
-	}
 
 	config_item_init_type_name(&hog->item, name,
 				   &gpio_sim_hog_config_type);
@@ -1359,8 +1293,6 @@ gpio_sim_line_config_make_hog_item(struct config_group *group, const char *name)
 	hog->parent = line;
 	line->hog = hog;
 
-	mutex_unlock(&dev->lock);
-
 	return &hog->item;
 }
 
@@ -1369,9 +1301,8 @@ static void gpio_sim_line_config_group_release(struct config_item *item)
 	struct gpio_sim_line *line = to_gpio_sim_line(item);
 	struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
 
-	mutex_lock(&dev->lock);
-	list_del(&line->siblings);
-	mutex_unlock(&dev->lock);
+	scoped_guard(mutex, &dev->lock)
+		list_del(&line->siblings);
 
 	kfree(line->name);
 	kfree(line);
@@ -1406,18 +1337,14 @@ gpio_sim_bank_config_make_line_group(struct config_group *group,
 	if (ret != 1 || nchar != strlen(name))
 		return ERR_PTR(-EINVAL);
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return ERR_PTR(-EBUSY);
-	}
 
 	line = kzalloc(sizeof(*line), GFP_KERNEL);
-	if (!line) {
-		mutex_unlock(&dev->lock);
+	if (!line)
 		return ERR_PTR(-ENOMEM);
-	}
 
 	config_group_init_type_name(&line->group, name,
 				    &gpio_sim_line_config_type);
@@ -1426,8 +1353,6 @@ gpio_sim_bank_config_make_line_group(struct config_group *group,
 	line->offset = offset;
 	list_add_tail(&line->siblings, &bank->line_list);
 
-	mutex_unlock(&dev->lock);
-
 	return &line->group;
 }
 
@@ -1436,9 +1361,8 @@ static void gpio_sim_bank_config_group_release(struct config_item *item)
 	struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
 	struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
 
-	mutex_lock(&dev->lock);
-	list_del(&bank->siblings);
-	mutex_unlock(&dev->lock);
+	scoped_guard(mutex, &dev->lock)
+		list_del(&bank->siblings);
 
 	kfree(bank->label);
 	kfree(bank);
@@ -1466,18 +1390,14 @@ gpio_sim_device_config_make_bank_group(struct config_group *group,
 	struct gpio_sim_device *dev = to_gpio_sim_device(&group->cg_item);
 	struct gpio_sim_bank *bank;
 
-	mutex_lock(&dev->lock);
+	guard(mutex)(&dev->lock);
 
-	if (gpio_sim_device_is_live_unlocked(dev)) {
-		mutex_unlock(&dev->lock);
+	if (gpio_sim_device_is_live_unlocked(dev))
 		return ERR_PTR(-EBUSY);
-	}
 
 	bank = kzalloc(sizeof(*bank), GFP_KERNEL);
-	if (!bank) {
-		mutex_unlock(&dev->lock);
+	if (!bank)
 		return ERR_PTR(-ENOMEM);
-	}
 
 	config_group_init_type_name(&bank->group, name,
 				    &gpio_sim_bank_config_group_type);
@@ -1486,8 +1406,6 @@ gpio_sim_device_config_make_bank_group(struct config_group *group,
 	INIT_LIST_HEAD(&bank->line_list);
 	list_add_tail(&bank->siblings, &dev->bank_list);
 
-	mutex_unlock(&dev->lock);
-
 	return &bank->group;
 }
 
@@ -1495,10 +1413,10 @@ static void gpio_sim_device_config_group_release(struct config_item *item)
 {
 	struct gpio_sim_device *dev = to_gpio_sim_device(item);
 
-	mutex_lock(&dev->lock);
-	if (gpio_sim_device_is_live_unlocked(dev))
-		gpio_sim_device_deactivate_unlocked(dev);
-	mutex_unlock(&dev->lock);
+	scoped_guard(mutex, &dev->lock) {
+		if (gpio_sim_device_is_live_unlocked(dev))
+			gpio_sim_device_deactivate_unlocked(dev);
+	}
 
 	mutex_destroy(&dev->lock);
 	ida_free(&gpio_sim_ida, dev->id);
@@ -1523,7 +1441,7 @@ static const struct config_item_type gpio_sim_device_config_group_type = {
 static struct config_group *
 gpio_sim_config_make_device_group(struct config_group *group, const char *name)
 {
-	struct gpio_sim_device *dev;
+	struct gpio_sim_device *dev __free(kfree) = NULL;
 	int id;
 
 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
@@ -1531,10 +1449,8 @@ gpio_sim_config_make_device_group(struct config_group *group, const char *name)
 		return ERR_PTR(-ENOMEM);
 
 	id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
-	if (id < 0) {
-		kfree(dev);
+	if (id < 0)
 		return ERR_PTR(id);
-	}
 
 	config_group_init_type_name(&dev->group, name,
 				    &gpio_sim_device_config_group_type);
@@ -1545,7 +1461,7 @@ gpio_sim_config_make_device_group(struct config_group *group, const char *name)
 	dev->bus_notifier.notifier_call = gpio_sim_bus_notifier_call;
 	init_completion(&dev->probe_completion);
 
-	return &dev->group;
+	return &no_free_ptr(dev)->group;
 }
 
 static struct configfs_group_operations gpio_sim_config_group_ops = {
-- 
2.39.2

Re: [PATCH v3] gpio: sim: simplify code with cleanup helpers

[Andy Shevchenko]

On Sat, Aug 12, 2023 at 08:36:35PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> Use macros defined in linux/cleanup.h to automate resource lifetime
> control in gpio-sim.

...

>  static void gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value)
>  {
>  	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
>  
> -	mutex_lock(&chip->lock);
> -	__assign_bit(offset, chip->value_map, value);
> -	mutex_unlock(&chip->lock);
> +	scoped_guard(mutex, &chip->lock)
> +		__assign_bit(offset, chip->value_map, value);

But this can also be guarded.

	guard(mutex)(&chip->lock);

	__assign_bit(offset, chip->value_map, value);

>  }

...

>  {
>  	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
>  
> -	mutex_lock(&chip->lock);
> -	bitmap_replace(chip->value_map, chip->value_map, bits, mask, gc->ngpio);
> -	mutex_unlock(&chip->lock);
> +	scoped_guard(mutex, &chip->lock)
> +		bitmap_replace(chip->value_map, chip->value_map, bits, mask,
> +			       gc->ngpio);

Ditto.

	guard(mutex)(&chip->lock);

	bitmap_replace(chip->value_map, chip->value_map, bits, mask, gc->ngpio);

(exactly 80 for the sectants of 80 characters :).

>  }

...

>  {
>  	struct gpio_sim_chip *chip = gpiochip_get_data(gc);
>  
> -	mutex_lock(&chip->lock);
> -	__assign_bit(offset, chip->value_map, !!test_bit(offset, chip->pull_map));
> -	mutex_unlock(&chip->lock);
> +	scoped_guard(mutex, &chip->lock)
> +		__assign_bit(offset, chip->value_map,
> +			     !!test_bit(offset, chip->pull_map));

Ditto.

	guard(mutex)(&chip->lock);

	__assign_bit(offset, chip->value_map, test_bit(offset, chip->pull_map));

(in this form fanatics of 80 can sleep well :-)

Note that !! is redundant as test_bit() family of functions were fixed to
return boolean.

>  }

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3] gpio: sim: simplify code with cleanup helpers

[Bartosz Golaszewski]

On Tue, Aug 15, 2023 at 12:31 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Sat, Aug 12, 2023 at 08:36:35PM +0200, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >
> > Use macros defined in linux/cleanup.h to automate resource lifetime
> > control in gpio-sim.
>
> ...
>
> >  static void gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value)
> >  {
> >       struct gpio_sim_chip *chip = gpiochip_get_data(gc);
> >
> > -     mutex_lock(&chip->lock);
> > -     __assign_bit(offset, chip->value_map, value);
> > -     mutex_unlock(&chip->lock);
> > +     scoped_guard(mutex, &chip->lock)
> > +             __assign_bit(offset, chip->value_map, value);
>
> But this can also be guarded.
>
>         guard(mutex)(&chip->lock);
>
>         __assign_bit(offset, chip->value_map, value);
>

Come on, this is total bikeshedding! I could produce ten arguments in
favor of the scoped variant.

Linus acked even the previous version and Peter says it looks right. I
will queue it unless some *real* issues come up.

> >  }
>
> ...
>
> >  {
> >       struct gpio_sim_chip *chip = gpiochip_get_data(gc);
> >
> > -     mutex_lock(&chip->lock);
> > -     bitmap_replace(chip->value_map, chip->value_map, bits, mask, gc->ngpio);
> > -     mutex_unlock(&chip->lock);
> > +     scoped_guard(mutex, &chip->lock)
> > +             bitmap_replace(chip->value_map, chip->value_map, bits, mask,
> > +                            gc->ngpio);
>
> Ditto.
>
>         guard(mutex)(&chip->lock);
>
>         bitmap_replace(chip->value_map, chip->value_map, bits, mask, gc->ngpio);
>
> (exactly 80 for the sectants of 80 characters :).
>
> >  }
>
> ...
>
> >  {
> >       struct gpio_sim_chip *chip = gpiochip_get_data(gc);
> >
> > -     mutex_lock(&chip->lock);
> > -     __assign_bit(offset, chip->value_map, !!test_bit(offset, chip->pull_map));
> > -     mutex_unlock(&chip->lock);
> > +     scoped_guard(mutex, &chip->lock)
> > +             __assign_bit(offset, chip->value_map,
> > +                          !!test_bit(offset, chip->pull_map));
>
> Ditto.
>
>         guard(mutex)(&chip->lock);
>
>         __assign_bit(offset, chip->value_map, test_bit(offset, chip->pull_map));
>
> (in this form fanatics of 80 can sleep well :-)
>
> Note that !! is redundant as test_bit() family of functions were fixed to
> return boolean.

Ha! TIL... I'll change it in a separate patch.

Bart

>
> >  }
>
> --
> With Best Regards,
> Andy Shevchenko
>
>

Re: [PATCH v3] gpio: sim: simplify code with cleanup helpers

[Andy Shevchenko]

On Tue, Aug 15, 2023 at 09:09:55PM +0200, Bartosz Golaszewski wrote:
> On Tue, Aug 15, 2023 at 12:31 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > On Sat, Aug 12, 2023 at 08:36:35PM +0200, Bartosz Golaszewski wrote:

...

> > > -     mutex_lock(&chip->lock);
> > > -     __assign_bit(offset, chip->value_map, value);
> > > -     mutex_unlock(&chip->lock);
> > > +     scoped_guard(mutex, &chip->lock)
> > > +             __assign_bit(offset, chip->value_map, value);
> >
> > But this can also be guarded.
> >
> >         guard(mutex)(&chip->lock);
> >
> >         __assign_bit(offset, chip->value_map, value);
> 
> Come on, this is total bikeshedding! I could produce ten arguments in
> favor of the scoped variant.
> 
> Linus acked even the previous version and Peter says it looks right. I
> will queue it unless some *real* issues come up.

I still think this will be, besides being shorter and nicer to read,
more consistent with other simple use of "guard(); return ..." cases.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3] gpio: sim: simplify code with cleanup helpers

[Bartosz Golaszewski]

On Thu, Aug 17, 2023 at 11:25 AM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Tue, Aug 15, 2023 at 09:09:55PM +0200, Bartosz Golaszewski wrote:
> > On Tue, Aug 15, 2023 at 12:31 PM Andy Shevchenko
> > <andriy.shevchenko@linux.intel.com> wrote:
> > > On Sat, Aug 12, 2023 at 08:36:35PM +0200, Bartosz Golaszewski wrote:
>
> ...
>
> > > > -     mutex_lock(&chip->lock);
> > > > -     __assign_bit(offset, chip->value_map, value);
> > > > -     mutex_unlock(&chip->lock);
> > > > +     scoped_guard(mutex, &chip->lock)
> > > > +             __assign_bit(offset, chip->value_map, value);
> > >
> > > But this can also be guarded.
> > >
> > >         guard(mutex)(&chip->lock);
> > >
> > >         __assign_bit(offset, chip->value_map, value);
> >
> > Come on, this is total bikeshedding! I could produce ten arguments in
> > favor of the scoped variant.
> >
> > Linus acked even the previous version and Peter says it looks right. I
> > will queue it unless some *real* issues come up.
>
> I still think this will be, besides being shorter and nicer to read,
> more consistent with other simple use of "guard(); return ..." cases.
>

Scoped guards have the advantage of making it very obvious where the
critical section ends. It's really down to personal preference,
there's nothing wrong with either option.

Bart

Re: [PATCH v3] gpio: sim: simplify code with cleanup helpers

[Bartosz Golaszewski]

On Sat, Aug 12, 2023 at 8:36 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> Use macros defined in linux/cleanup.h to automate resource lifetime
> control in gpio-sim.
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> ---

I queued v3.

Bart