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 intel_uncore_box { ... struct intel_uncore_extra_reg shared_regs[0]; }; size = sizeof(struct intel_uncore_box) + count * sizeof(struct intel_uncore_extra_reg); instance = kzalloc_node(size, GFP_KERNEL, node); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kzalloc_node(struct_size(instance, shared_regs, count), GFP_KERNEL, node); Notice that, in this case, variable size 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> --- arch/x86/events/intel/uncore.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c index 3694a5d0703d..013768dc8f37 100644 --- a/arch/x86/events/intel/uncore.c +++ b/arch/x86/events/intel/uncore.c @@ -313,12 +313,11 @@ static void uncore_pmu_init_hrtimer(struct intel_uncore_box *box) static struct intel_uncore_box *uncore_alloc_box(struct intel_uncore_type *type, int node) { - int i, size, numshared = type->num_shared_regs ; + int i, numshared = type->num_shared_regs; struct intel_uncore_box *box; - size = sizeof(*box) + numshared * sizeof(struct intel_uncore_extra_reg); - - box = kzalloc_node(size, GFP_KERNEL, node); + box = kzalloc_node(struct_size(box, shared_regs, numshared), GFP_KERNEL, + node); if (!box) return NULL; -- 2.22.0