mtd: lpddr: Use struct_size() in 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 = kzalloc(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 = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

---
 drivers/mtd/lpddr/qinfo_probe.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 69f2112340b1..175bdc3b72f4 100644
@@ -181,8 +181,8 @@ static struct lpddr_private *lpddr_probe_chip(struct map_info *map)
 	lpddr.numchips = 1;
 
 	numvirtchips = lpddr.numchips * lpddr.qinfo->HWPartsNum;
-	retlpddr = kzalloc(sizeof(struct lpddr_private) +
-			numvirtchips * sizeof(struct flchip), GFP_KERNEL);
+	retlpddr = kzalloc(struct_size(retlpddr, chips, numvirtchips),
+			   GFP_KERNEL);
 	if (!retlpddr)
 		return NULL;
 

2.20.1

From: Boris Brezillon <[email protected]>

Applied to http://git.infradead.org/linux-mtd.git mtd/next, thanks.

Boris