[PATCH][next] USB: serial: ti_usb_3410_5052: Use struct_size() helper in ti_write_byte()

["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/usb/serial/ti_usb_3410_5052.c:1521:16: 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/usb/serial/ti_usb_3410_5052.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c
index 18c0bd853392..03f98e61626f 100644
--- a/drivers/usb/serial/ti_usb_3410_5052.c
+++ b/drivers/usb/serial/ti_usb_3410_5052.c
@@ -1512,13 +1512,13 @@ static int ti_write_byte(struct usb_serial_port *port,
 			 u8 mask, u8 byte)
 {
 	int status;
-	unsigned int size;
+	size_t size;
 	struct ti_write_data_bytes *data;
 
 	dev_dbg(&port->dev, "%s - addr 0x%08lX, mask 0x%02X, byte 0x%02X\n", __func__,
 		addr, mask, byte);
 
-	size = sizeof(struct ti_write_data_bytes) + 2;
+	size = struct_size(data, bData, 2);
 	data = kmalloc(size, GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
-- 
2.27.0