[PATCH net-next] cxgb4: smt: use struct_size() in kvzalloc()

From: Gustavo A. R. Silva
Date: Wed Jan 30 2019 - 19:27:50 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;
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.

Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
---
drivers/net/ethernet/chelsio/cxgb4/smt.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4/smt.c b/drivers/net/ethernet/chelsio/cxgb4/smt.c
index 7b2207a2a130..eaf1fb74689c 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/smt.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/smt.c
@@ -47,8 +47,7 @@ struct smt_data *t4_init_smt(void)

smt_size = SMT_SIZE;

- s = kvzalloc(sizeof(*s) + smt_size * sizeof(struct smt_entry),
- GFP_KERNEL);
+ s = kvzalloc(struct_size(s, smtab, smt_size), GFP_KERNEL);
if (!s)
return NULL;
s->smt_size = smt_size;
--
2.20.1