[PATCH 2/2 v2] gpio: sim: simplify code with cleanup helpers

From: Bartosz Golaszewski
Date: Fri Aug 11 2023 - 09:14:40 EST


From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>

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

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
---
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 | 250 ++++++++++++++--------------------------
1 file changed, 85 insertions(+), 165 deletions(-)

diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index 0177b41e0d72..5f6c2826c70e 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)) {
@@ -104,7 +105,6 @@ 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;
}

@@ -113,9 +113,8 @@ 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);
+ scoped_guard(mutex, &chip->lock)
+ ret = !!test_bit(offset, chip->value_map);

return ret;
}
@@ -124,9 +123,8 @@ 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 +132,8 @@ 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 +143,9 @@ 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 +153,10 @@ 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 +165,8 @@ 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 +176,8 @@ 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 +210,9 @@ 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 +222,8 @@ 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 +252,8 @@ 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 +652,14 @@ 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 +670,8 @@ 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 +826,7 @@ 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 +845,7 @@ 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 +970,7 @@ 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 +979,6 @@ 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 +1015,14 @@ 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 +1032,10 @@ 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 +1045,18 @@ 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 +1067,10 @@ 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 +1089,13 @@ 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 +1113,10 @@ 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 +1126,18 @@ 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;
}

@@ -1197,9 +1155,8 @@ static ssize_t gpio_sim_hog_config_name_show(struct config_item *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);
+ scoped_guard(mutex, &dev->lock)
+ ret = sprintf(page, "%s\n", hog->name ?: "");

return ret;
}
@@ -1211,24 +1168,18 @@ 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 +1193,8 @@ 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 +1223,10 @@ 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 +1235,10 @@ 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 +1256,8 @@ 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 +1283,11 @@ 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 +1297,6 @@ 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 +1305,8 @@ 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 +1341,14 @@ 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 +1357,6 @@ 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 +1365,8 @@ 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 +1394,14 @@ 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 +1410,6 @@ 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 +1417,10 @@ 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 +1445,7 @@ 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 +1453,8 @@ 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 +1465,7 @@ 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