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; void *entry[]; }; instance = alloc(sizeof(struct foo) + count * sizeof(void *)); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = alloc(struct_size(instance, entry, count)); This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx> --- drivers/net/usb/cdc-phonet.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/usb/cdc-phonet.c b/drivers/net/usb/cdc-phonet.c index 78b16eb9e58c..63aaae487995 100644 --- a/drivers/net/usb/cdc-phonet.c +++ b/drivers/net/usb/cdc-phonet.c @@ -361,8 +361,8 @@ static int usbpn_probe(struct usb_interface *intf, const struct usb_device_id *i else return -EINVAL; - dev = alloc_netdev(sizeof(*pnd) + sizeof(pnd->urbs[0]) * rxq_size, - ifname, NET_NAME_UNKNOWN, usbpn_setup); + dev = alloc_netdev(struct_size(pnd, urbs, rxq_size), ifname, + NET_NAME_UNKNOWN, usbpn_setup); if (!dev) return -ENOMEM; -- 2.20.1