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 = devm_kzalloc(dev, size, 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, entry, count), GFP_KERNEL);
Notice that, in this case, variable sz is not necessary, hence it
is removed.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gust...@embeddedor.com>
---
kernel/irq/devres.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/irq/devres.c b/kernel/irq/devres.c
index f808c6a97dcc..f6e5515ee077 100644
--- a/kernel/irq/devres.c
+++ b/kernel/irq/devres.c
@@ -220,9 +220,8 @@ devm_irq_alloc_generic_chip(struct device *dev, const char
*name, int num_ct,
irq_flow_handler_t handler)
{
struct irq_chip_generic *gc;
- unsigned long sz = sizeof(*gc) + num_ct * sizeof(struct irq_chip_type);
- gc = devm_kzalloc(dev, sz, GFP_KERNEL);
+ gc = devm_kzalloc(dev, struct_size(gc, chip_types, num_ct), GFP_KERNEL);
if (gc)
irq_init_generic_chip(gc, name, num_ct,
irq_base, reg_base, handler);
--
2.21.0
