On Thu, Mar 26, 2026 at 4:33 AM Lee Jones <[email protected]> wrote:
>
> On Thu, 19 Mar 2026, Rosen Penev wrote:
>
> > 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 <[email protected]>
> > ---
> > 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);
>
> Where is the memory allocated to this now?
The kzalloc call was updated to use struct_size to allocate it
together with the struct.
>
> Why do we need this in both structs?
kzalloc and kcalloc can be combined in both locations.
>
> > +};
> > +
> > +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
> >
>
> --
> Lee Jones [李琼斯]
