[PATCH] leds: pca955x: kzalloc + kcalloc to single kzalloc

Rosen Penev
2026-03-20T04:08:41Z

Two fewer allocations as a result.

Required placing some structs before others as flexible array members
require a complete definition. Declaration is not enough.

Added __counted_by support for one of the structs for extra runtime
analysis.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
drivers/leds/leds-pca955x.c | 45 ++++++++++++++-----------------------
1 file changed, 17 insertions(+), 28 deletions(-)

diff --git a/drivers/leds/leds-pca955x.c b/drivers/leds/leds-pca955x.c
index 2007fe6217ec..ee5f02eaa3c9 100644
--- a/drivers/leds/leds-pca955x.c
+++ b/drivers/leds/leds-pca955x.c
@@ -112,19 +112,6 @@ static const struct pca955x_chipdef pca955x_chipdefs[] = {
},
};

-struct pca955x {
- struct mutex lock;
- struct pca955x_led *leds;
- const struct pca955x_chipdef *chipdef;
- struct i2c_client *client;
- unsigned long active_blink;
- unsigned long active_pins;
- unsigned long blink_period;
-#ifdef CONFIG_LEDS_PCA955X_GPIO
- struct gpio_chip gpio;
-#endif
-};
-
struct pca955x_led {
struct pca955x *pca955x;
struct led_classdev led_cdev;
@@ -137,8 +124,21 @@ struct pca955x_led {
#define led_to_pca955x(l) container_of(l, struct pca955x_led, led_cdev)

struct pca955x_platform_data {
- struct pca955x_led *leds;
int num_leds;
+ struct pca955x_led leds[] __counted_by(num_leds);
+};
+
+struct pca955x {
+ struct mutex lock;
+ const struct pca955x_chipdef *chipdef;
+ struct i2c_client *client;
+ unsigned long active_blink;
+ unsigned long active_pins;
+ unsigned long blink_period;
+#ifdef CONFIG_LEDS_PCA955X_GPIO
+ struct gpio_chip gpio;
+#endif
+ struct pca955x_led leds[];
};

/* 8 bits per input register */
@@ -542,15 +542,11 @@ pca955x_get_pdata(struct i2c_client *client, const struct pca955x_chipdef *chip)
if (count > chip->bits)
return ERR_PTR(-ENODEV);

- pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
+ pdata = devm_kzalloc(&client->dev, struct_size(pdata, leds, chip->bits), GFP_KERNEL);
if (!pdata)
return ERR_PTR(-ENOMEM);

- pdata->leds = devm_kcalloc(&client->dev,
- chip->bits, sizeof(struct pca955x_led),
- GFP_KERNEL);
- if (!pdata->leds)
- return ERR_PTR(-ENOMEM);
+ pdata->num_leds = chip->bits;

device_for_each_child_node(&client->dev, child) {
u32 reg;
@@ -568,8 +564,6 @@ pca955x_get_pdata(struct i2c_client *client, const struct pca955x_chipdef *chip)
fwnode_property_read_u32(child, "type", &led->type);
}

- pdata->num_leds = chip->bits;
-
return pdata;
}

@@ -623,15 +617,10 @@ static int pca955x_probe(struct i2c_client *client)
return -ENODEV;
}

- pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
+ pca955x = devm_kzalloc(&client->dev, struct_size(pca955x, leds, chip->bits), GFP_KERNEL);
if (!pca955x)
return -ENOMEM;

- pca955x->leds = devm_kcalloc(&client->dev, chip->bits,
- sizeof(*pca955x_led), GFP_KERNEL);
- if (!pca955x->leds)
- return -ENOMEM;
-
i2c_set_clientdata(client, pca955x);

mutex_init(&pca955x->lock);
--
2.53.0