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 gpio_keys_polled_dev {
...
struct gpio_keys_button_data data[0];
};
size = sizeof(struct gpio_keys_polled_dev) + count * sizeof(struct gpio_keys_button_data);
instance = devm_kzalloc(dev, size, 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, data, count), GFP_KERNEL);
Notice that, in this case, variable size is not necessary, hence it
is removed.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
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