cpu_cf_ptr
struct cpu_cf_ptr __percpu *cfptr;
struct cpu_cf_ptr __percpu *p = cpu_cf_root.cfptr;
struct cpu_cf_ptr *q = per_cpu_ptr(p, cpu);
cpu_cf_root.cfptr = alloc_percpu(struct cpu_cf_ptr);
struct cpu_cf_ptr *p;
struct cpu_cf_ptr *p;