Bluetooth: a2mp: Use struct_size() helper

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[];
};

size = sizeof(struct foo) + count * sizeof(struct boo);
instance = alloc(size, GFP_KERNEL)

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

size = struct_size(instance, entry, count);
instance = alloc(size, GFP_KERNEL)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/net/bluetooth/a2mp.c b/net/bluetooth/a2mp.c
index 58fc633..5f918ea 100644 (file)
--- a/net/bluetooth/a2mp.c
+++ b/net/bluetooth/a2mp.c
@@ -174,7 +174,7 @@ static int a2mp_discover_req(struct amp_mgr *mgr, struct sk_buff *skb,
                        num_ctrl++;
        }
 
-       len = num_ctrl * sizeof(struct a2mp_cl) + sizeof(*rsp);
+       len = struct_size(rsp, cl, num_ctrl);
        rsp = kmalloc(len, GFP_ATOMIC);
        if (!rsp) {
                read_unlock(&hci_dev_list_lock);