Re: [PATCH] serial: max310x: Use struct_size() in devm_kzalloc()

[Jan Kundrát]

On pátek 4. ledna 2019 22:39:13 CET, Gustavo A. R. Silva wrote:

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;
    void *entry[];
};

instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, 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 <gust...@embeddedor.com>
---
 drivers/tty/serial/max310x.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index 4f479841769a..1d700a8ab517 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c

@@ -1197,8 +1197,7 @@ static int max310x_probe(struct device *dev, struct max310x_devtype *devtype,

                return PTR_ERR(regmap);

/* Alloc port structure */

-       s = devm_kzalloc(dev, sizeof(*s) +
-                        sizeof(struct max310x_one) * devtype->nr, GFP_KERNEL);
+       s = devm_kzalloc(dev, struct_size(s, p, devtype->nr), GFP_KERNEL);
        if (!s) {
                dev_err(dev, "Error allocating port structure\n");
                return -ENOMEM;

Reviewed-by: Jan Kundrát <jan.kund...@cesnet.cz>
Tested-by: Jan Kundrát <jan.kund...@cesnet.cz>