gpio: dwapb: reduce allocation to single kzalloc

Instead of kzalloc + kcalloc, Combine the two using a flexible array
member.

Allows using __counted_by for extra runtime analysis. Move counting
variable to right after allocation as required by __counted_by.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Link: https://patch.msgid.link/20260320005338.30355-1-rosenp@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

Author: neheb

drivers/gpio/gpio-dwapb.c

@@ -75,8 +75,8 @@ struct dwapb_port_property {
 };
 
 struct dwapb_platform_data {
-	struct dwapb_port_property *properties;
 	unsigned int nports;
+	struct dwapb_port_property properties[] __counted_by(nports);
 };
 
 /* Store GPIO context across system-wide suspend/resume transitions */
@@ -114,11 +114,11 @@ static inline struct dwapb_gpio *to_dwapb_gpio(struct gpio_chip *gc)
 struct dwapb_gpio {
 	struct	device		*dev;
 	void __iomem		*regs;
-	struct dwapb_gpio_port	*ports;
 	unsigned int		nr_ports;
 	unsigned int		flags;
 	struct reset_control	*rst;
 	struct clk_bulk_data	clks[DWAPB_NR_CLOCKS];
+	struct dwapb_gpio_port	ports[] __counted_by(nr_ports);
 };
 
 static inline u32 gpio_reg_v2_convert(unsigned int offset)
@@ -585,14 +585,10 @@ static struct dwapb_platform_data *dwapb_gpio_get_pdata(struct device *dev)
 	if (nports == 0)
 		return ERR_PTR(-ENODEV);
 
-	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+	pdata = devm_kzalloc(dev, struct_size(pdata, properties, nports), GFP_KERNEL);
 	if (!pdata)
 		return ERR_PTR(-ENOMEM);
 
-	pdata->properties = devm_kcalloc(dev, nports, sizeof(*pp), GFP_KERNEL);
-	if (!pdata->properties)
-		return ERR_PTR(-ENOMEM);
-
 	pdata->nports = nports;
 
 	i = 0;
@@ -714,22 +710,17 @@ static int dwapb_gpio_probe(struct platform_device *pdev)
 	if (IS_ERR(pdata))
 		return PTR_ERR(pdata);
 
-	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
+	gpio = devm_kzalloc(&pdev->dev, struct_size(gpio, ports, pdata->nports), GFP_KERNEL);
 	if (!gpio)
 		return -ENOMEM;
 
-	gpio->dev = &pdev->dev;
 	gpio->nr_ports = pdata->nports;
+	gpio->dev = &pdev->dev;
 
 	err = dwapb_get_reset(gpio);
 	if (err)
 		return err;
 
-	gpio->ports = devm_kcalloc(&pdev->dev, gpio->nr_ports,
-				   sizeof(*gpio->ports), GFP_KERNEL);
-	if (!gpio->ports)
-		return -ENOMEM;
-
 	gpio->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(gpio->regs))
 		return PTR_ERR(gpio->regs);