[PATCH net-next] tulip: eeprom: use struct_size() in kmalloc()

Gustavo A. R. Silva
2019-01-31T00:56:36Z

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

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
drivers/net/ethernet/dec/tulip/eeprom.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/dec/tulip/eeprom.c b/drivers/net/ethernet/dec/tulip/eeprom.c
index 1812f4916917..ba0a69b363f8 100644
--- a/drivers/net/ethernet/dec/tulip/eeprom.c
+++ b/drivers/net/ethernet/dec/tulip/eeprom.c
@@ -224,9 +224,7 @@ void tulip_parse_eeprom(struct net_device *dev)
return;
}

- mtable = kmalloc(sizeof(struct mediatable) +
- count * sizeof(struct medialeaf),
- GFP_KERNEL);
+ mtable = kmalloc(struct_size(mtable, mleaf, count), GFP_KERNEL);
if (mtable == NULL)
return; /* Horrible, impossible failure. */
last_mediatable = tp->mtable = mtable;
--
2.20.1