prot_inuse
struct prot_inuse __percpu *prot_inuse;
struct prot_inuse;
this_cpu_add(net->core.prot_inuse->val[prot->inuse_idx], val);
this_cpu_add(net->core.prot_inuse->all, val);
res += per_cpu_ptr(net->core.prot_inuse, cpu)->val[idx];
res += per_cpu_ptr(net->core.prot_inuse, cpu)->all;
net->core.prot_inuse = alloc_percpu(struct prot_inuse);
if (net->core.prot_inuse == NULL)
free_percpu(net->core.prot_inuse);