[PATCHv2] gpio: ljca: reduce struct allocation

[Rosen Penev <rosenp@gmail.com>]

Convert connect_mode to a flexible array member to avoid calling
kcalloc and to combine the allocations.

Add __counted_by for extra runtime analysis.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 v2: add counting variable
 drivers/gpio/gpio-ljca.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpio-ljca.c b/drivers/gpio/gpio-ljca.c
index f32d1d237795..61252e0eb444 100644
--- a/drivers/gpio/gpio-ljca.c
+++ b/drivers/gpio/gpio-ljca.c
@@ -63,7 +63,6 @@ struct ljca_gpio_dev {
 	DECLARE_BITMAP(enabled_irqs, LJCA_MAX_GPIO_NUM);
 	DECLARE_BITMAP(reenable_irqs, LJCA_MAX_GPIO_NUM);
 	DECLARE_BITMAP(output_enabled, LJCA_MAX_GPIO_NUM);
-	u8 *connect_mode;
 	/* protect irq bus */
 	struct mutex irq_lock;
 	struct work_struct work;
@@ -72,6 +71,9 @@ struct ljca_gpio_dev {

 	u8 obuf[LJCA_GPIO_BUF_SIZE];
 	u8 ibuf[LJCA_GPIO_BUF_SIZE];
+
+	size_t num;
+	u8 connect_mode[] __counted_by(num);
 };

 static int ljca_gpio_config(struct ljca_gpio_dev *ljca_gpio, u8 gpio_id,
@@ -400,22 +402,20 @@ static int ljca_gpio_probe(struct auxiliary_device *auxdev,
 			   const struct auxiliary_device_id *aux_dev_id)
 {
 	struct ljca_client *ljca = auxiliary_dev_to_ljca_client(auxdev);
+	struct ljca_gpio_info *gpio_info = dev_get_platdata(&auxdev->dev);
 	struct ljca_gpio_dev *ljca_gpio;
 	struct gpio_irq_chip *girq;
 	int ret;

-	ljca_gpio = devm_kzalloc(&auxdev->dev, sizeof(*ljca_gpio), GFP_KERNEL);
+	ljca_gpio = devm_kzalloc(&auxdev->dev,
+				 struct_size(ljca_gpio, connect_mode, gpio_info->num),
+				 GFP_KERNEL);
 	if (!ljca_gpio)
 		return -ENOMEM;

+	ljca_gpio->num = gpio_info->num;
 	ljca_gpio->ljca = ljca;
-	ljca_gpio->gpio_info = dev_get_platdata(&auxdev->dev);
-	ljca_gpio->connect_mode = devm_kcalloc(&auxdev->dev,
-					       ljca_gpio->gpio_info->num,
-					       sizeof(*ljca_gpio->connect_mode),
-					       GFP_KERNEL);
-	if (!ljca_gpio->connect_mode)
-		return -ENOMEM;
+	ljca_gpio->gpio_info = gpio_info;

 	ret = devm_mutex_init(&auxdev->dev, &ljca_gpio->irq_lock);
 	if (ret)
--
2.53.0