[PATCH][next] extcon: usbc-cros-ec: Use struct_size() helper in kzalloc()

["Gustavo A. R. Silva" <gustavoars@kernel.org>]

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/extcon/extcon-usbc-cros-ec.c:71:23: warning: using sizeof on a flexible structure

Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/extcon/extcon-usbc-cros-ec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/extcon/extcon-usbc-cros-ec.c b/drivers/extcon/extcon-usbc-cros-ec.c
index 5290cc2d19d9..fde1db62be0d 100644
--- a/drivers/extcon/extcon-usbc-cros-ec.c
+++ b/drivers/extcon/extcon-usbc-cros-ec.c
@@ -68,7 +68,7 @@ static int cros_ec_pd_command(struct cros_ec_extcon_info *info,
 	struct cros_ec_command *msg;
 	int ret;
 
-	msg = kzalloc(sizeof(*msg) + max(outsize, insize), GFP_KERNEL);
+	msg = kzalloc(struct_size(msg, data, max(outsize, insize)), GFP_KERNEL);
 	if (!msg)
 		return -ENOMEM;
 
-- 
2.27.0