mfd: sm501: Use struct_size() in devm_kzalloc()

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct foo {
    int stuff;
    struct boo entry[];
};

instance = devm_kzalloc(dev, sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/sm501.c b/drivers/mfd/sm501.c
index e0173bf4b0dc7e15c39fffb278dc100e29eb03b6..d217debf382eb502ada83c67205bcf84ab1f64f0 100644 (file)
--- a/drivers/mfd/sm501.c
+++ b/drivers/mfd/sm501.c
@@ -1142,8 +1142,7 @@ static int sm501_register_gpio_i2c_instance(struct sm501_devdata *sm,
                return -ENOMEM;
 
        /* Create a gpiod lookup using gpiochip-local offsets */
-       lookup = devm_kzalloc(&pdev->dev,
-                             sizeof(*lookup) + 3 * sizeof(struct gpiod_lookup),
+       lookup = devm_kzalloc(&pdev->dev, struct_size(lookup, table, 3),
                              GFP_KERNEL);
        if (!lookup)
                return -ENOMEM;