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 samsung_usb2_phy_driver {
...
struct samsung_usb2_phy_instance instances[0];
};
instance = devm_kzalloc(dev, sizeof(struct samsung_usb2_phy_driver) +
count * sizeof(struct samsung_usb2_phy_instance),
GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = devm_kzalloc(dev, struct_size(instance, instances, 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: Kishon Vijay Abraham I <kishon@ti.com>
if (!cfg)
return -EINVAL;
- drv = devm_kzalloc(dev, sizeof(struct samsung_usb2_phy_driver) +
- cfg->num_phys * sizeof(struct samsung_usb2_phy_instance),
- GFP_KERNEL);
+ drv = devm_kzalloc(dev, struct_size(drv, instances, cfg->num_phys),
+ GFP_KERNEL);
if (!drv)
return -ENOMEM;