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 tp_probes {
...
struct tracepoint_func probes[0];
};
instance = kmalloc(sizeof(sizeof(struct tp_probes) +
sizeof(struct tracepoint_func) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kmalloc(struct_size(instance, probes, count) GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
kernel/tracepoint.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index df3ade14ccbd..73956eaff8a9 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -55,8 +55,8 @@ struct tp_probes {
static inline void *allocate_probes(int count)
{
- struct tp_probes *p = kmalloc(count * sizeof(struct tracepoint_func)
- + sizeof(struct tp_probes), GFP_KERNEL);
+ struct tp_probes *p = kmalloc(struct_size(p, probes, count),
+ GFP_KERNEL);
return p == NULL ? NULL : p->probes;
}
--
2.21.0
