[PATCH][next] nfp: flower: Use struct_size() helper in kmalloc()

[Gustavo A. R. Silva]

Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worst scenario, could lead to heap overflows.

Also, address the following sparse warnings:
drivers/net/ethernet/netronome/nfp/flower/tunnel_conf.c:359:25: warning: using sizeof on a flexible structure

Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
 drivers/net/ethernet/netronome/nfp/flower/tunnel_conf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/netronome/nfp/flower/tunnel_conf.c b/drivers/net/ethernet/netronome/nfp/flower/tunnel_conf.c
index dfb4468fe287..ce865e619568 100644
--- a/drivers/net/ethernet/netronome/nfp/flower/tunnel_conf.c
+++ b/drivers/net/ethernet/netronome/nfp/flower/tunnel_conf.c
@@ -356,7 +356,7 @@ __nfp_tun_add_route_to_cache(struct list_head *route_list,
 			return 0;
 		}
 
-	entry = kmalloc(sizeof(*entry) + add_len, GFP_ATOMIC);
+	entry = kmalloc(struct_size(entry, ip_add, add_len), GFP_ATOMIC);
 	if (!entry) {
 		spin_unlock_bh(list_lock);
 		return -ENOMEM;
-- 
2.27.0