include/linux/percpu.h

   1 #ifndef __LINUX_PERCPU_H
   2 #define __LINUX_PERCPU_H
   3
   4 #include <linux/spinlock.h> /* For preempt_disable() */
   5 #include <linux/slab.h> /* For kmalloc() */
   6 #include <linux/smp.h>
   7 #include <linux/string.h> /* For memset() */
   8 #include <linux/cpumask.h>
   9
  10 #include <asm/percpu.h>
  11
  12 /* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
  13 #ifndef PERCPU_ENOUGH_ROOM
  14 #define PERCPU_ENOUGH_ROOM 32768
  15 #endif
  16
  17 /*
  18  * Must be an lvalue. Since @var must be a simple identifier,
  19  * we force a syntax error here if it isn't.
  20  */
  21 #define get_cpu_var(var) (*({                           \
  22         extern int simple_identifier_##var(void);       \
  23         preempt_disable();                              \
  24         &__get_cpu_var(var); }))
  25 #define put_cpu_var(var) preempt_enable()
  26
  27 #ifdef CONFIG_SMP
  28
  29 struct percpu_data {
  30         void *ptrs[NR_CPUS];
  31 };
  32
  33 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
  34 /*
  35  * Use this to get to a cpu's version of the per-cpu object dynamically
  36  * allocated. Non-atomic access to the current CPU's version should
  37  * probably be combined with get_cpu()/put_cpu().
  38  */
  39 #define percpu_ptr(ptr, cpu)                              \
  40 ({                                                        \
  41         struct percpu_data *__p = __percpu_disguise(ptr); \
  42         (__typeof__(ptr))__p->ptrs[(cpu)];                \
  43 })
  44
  45 extern void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu);
  46 extern void percpu_depopulate(void *__pdata, int cpu);
  47 extern int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
  48                                   cpumask_t *mask);
  49 extern void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask);
  50 extern void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask);
  51 extern void percpu_free(void *__pdata);
  52
  53 #else /* CONFIG_SMP */
  54
  55 #define percpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
  56
  57 static inline void percpu_depopulate(void *__pdata, int cpu)
  58 {
  59 }
  60
  61 static inline void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask)
  62 {
  63 }
  64
  65 static inline void *percpu_populate(void *__pdata, size_t size, gfp_t gfp,
  66                                     int cpu)
  67 {
  68         return percpu_ptr(__pdata, cpu);
  69 }
  70
  71 static inline int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
  72                                          cpumask_t *mask)
  73 {
  74         return 0;
  75 }
  76
  77 static __always_inline void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
  78 {
  79         return kzalloc(size, gfp);
  80 }
  81
  82 static inline void percpu_free(void *__pdata)
  83 {
  84         kfree(__pdata);
  85 }
  86
  87 #endif /* CONFIG_SMP */
  88
  89 #define percpu_populate_mask(__pdata, size, gfp, mask) \
  90         __percpu_populate_mask((__pdata), (size), (gfp), &(mask))
  91 #define percpu_depopulate_mask(__pdata, mask) \
  92         __percpu_depopulate_mask((__pdata), &(mask))
  93 #define percpu_alloc_mask(size, gfp, mask) \
  94         __percpu_alloc_mask((size), (gfp), &(mask))
  95
  96 #define percpu_alloc(size, gfp) percpu_alloc_mask((size), (gfp), cpu_online_map)
  97
  98 /* (legacy) interface for use without CPU hotplug handling */
  99
 100 #define __alloc_percpu(size)    percpu_alloc_mask((size), GFP_KERNEL, \
 101                                                   cpu_possible_map)
 102 #define alloc_percpu(type)      (type *)__alloc_percpu(sizeof(type))
 103 #define free_percpu(ptr)        percpu_free((ptr))
 104 #define per_cpu_ptr(ptr, cpu)   percpu_ptr((ptr), (cpu))
 105
 106 #endif /* __LINUX_PERCPU_H */