[PATCH] mtd: rawnand: sunxi: Use struct_size() in devm_kzalloc()

From: Gustavo A. R. Silva
Date: Fri Jan 04 2019 - 12:26:45 EST

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 <gustavo@xxxxxxxxxxxxxx>
drivers/mtd/nand/raw/sunxi_nand.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/mtd/nand/raw/sunxi_nand.c b/drivers/mtd/nand/raw/sunxi_nand.c
index e828ee50a201..f66fffe663bf 100644
--- a/drivers/mtd/nand/raw/sunxi_nand.c
+++ b/drivers/mtd/nand/raw/sunxi_nand.c
@@ -1870,10 +1870,7 @@ static int sunxi_nand_chip_init(struct device *dev, struct sunxi_nfc *nfc,
return -EINVAL;

- chip = devm_kzalloc(dev,
- sizeof(*chip) +
- (nsels * sizeof(struct sunxi_nand_chip_sel)),
+ chip = devm_kzalloc(dev, struct_size(chip, sels, nsels), GFP_KERNEL);
if (!chip) {
dev_err(dev, "could not allocate chip\n");
return -ENOMEM;