Subject: [PATCH net-next] nfp: use struct_size() in kzalloc()

From: "Gustavo A. R. Silva" <[email-masked]>
Date: Wed, 30 Jan 2019 18:38:59 -0600

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

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <[email-masked]>
---
 drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c
index 802c9224bb32..f6f028fa5db9 100644
--- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c
+++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c
@@ -269,8 +269,7 @@ __nfp_eth_read_ports(struct nfp_cpp *cpp, struct nfp_nsp *nsp)
 		goto err;
 	}
 
-	table = kzalloc(sizeof(*table) +
-			sizeof(struct nfp_eth_table_port) * cnt, GFP_KERNEL);
+	table = kzalloc(struct_size(table, ports, cnt), GFP_KERNEL);
 	if (!table)
 		goto err;
 
-- 
2.20.1