tracepoint: Use struct_size() in kmalloc()

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 <gustavo@embeddedor.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Gustavo A. R. Silva 2019-06-10 16:22:19 -05:00 committed by Steven Rostedt (VMware)
parent 86b3de60a0
commit f0553dcb97

View File

@ -68,8 +68,8 @@ 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;
}