openvswitch: meter: Use struct_size() in kzalloc()

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[];
};

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

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

instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/openvswitch/meter.c b/net/openvswitch/meter.c
index c038e021a591685cd9cca521c5b32259ea48bdbd..43849d752a1e72e5bcefa74d72ca78a84fd97a12 100644 (file)
--- a/net/openvswitch/meter.c
+++ b/net/openvswitch/meter.c
@@ -206,8 +206,7 @@ static struct dp_meter *dp_meter_create(struct nlattr **a)
                        return ERR_PTR(-EINVAL);
 
        /* Allocate and set up the meter before locking anything. */
-       meter = kzalloc(n_bands * sizeof(struct dp_meter_band) +
-                       sizeof(*meter), GFP_KERNEL);
+       meter = kzalloc(struct_size(meter, bands, n_bands), GFP_KERNEL);
        if (!meter)
                return ERR_PTR(-ENOMEM);