cxgb4: sched: use struct_size() in kvzalloc()

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;
    struct boo entry[];
};

instance = kvzalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper:

instance = kvzalloc(struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

---
 drivers/net/ethernet/chelsio/cxgb4/sched.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 52edb688942b..ba6c153ee45c 100644
@@ -478,7 +478,7 @@ struct sched_table *t4_init_sched(unsigned int sched_size)
 	struct sched_table *s;
 	unsigned int i;
 
-	s = kvzalloc(sizeof(*s) + sched_size * sizeof(struct sched_class), GFP_KERNEL);
+	s = kvzalloc(struct_size(s, tab, sched_size), GFP_KERNEL);
 	if (!s)
 		return NULL;
 

2.20.1

From: "Gustavo A. R. Silva" <[email protected]>
Date: Wed, 30 Jan 2019 18:23:14 -0600

Applied.