mtd: rawnand: marvell: 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;
    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.

---
 drivers/mtd/nand/raw/marvell_nand.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

index 84283c6bb0ff..f38e5c1b87e4 100644
@@ -2550,9 +2550,8 @@ static int marvell_nand_chip_init(struct device *dev, struct marvell_nfc *nfc,
 	}
 
 	/* Alloc the nand chip structure */
-	marvell_nand = devm_kzalloc(dev, sizeof(*marvell_nand) +
-				    (nsels *
-				     sizeof(struct marvell_nand_chip_sel)),
+	marvell_nand = devm_kzalloc(dev,
+				    struct_size(marvell_nand, sels, nsels),
 				    GFP_KERNEL);
 	if (!marvell_nand) {
 		dev_err(dev, "could not allocate chip structure\n");

2.20.1

Hi Gustavo,

"Gustavo A. R. Silva" <[email protected]> wrote on Fri, 4 Jan 2019 12:20:51 -0600:

Applied to nand/next.

Thanks,
Miquèl

Thanks, Miquèl.

--
Gustavo