include/linux/ratelimit.h

   1 #ifndef _LINUX_RATELIMIT_H
   2 #define _LINUX_RATELIMIT_H
   3
   4 #include <linux/param.h>
   5 #include <linux/sched.h>
   6 #include <linux/spinlock.h>
   7
   8 #define DEFAULT_RATELIMIT_INTERVAL      (5 * HZ)
   9 #define DEFAULT_RATELIMIT_BURST         10
  10
  11 /* issue num suppressed message on exit */
  12 #define RATELIMIT_MSG_ON_RELEASE        BIT(0)
  13
  14 struct ratelimit_state {
  15         raw_spinlock_t  lock;           /* protect the state */
  16
  17         int             interval;
  18         int             burst;
  19         int             printed;
  20         int             missed;
  21         unsigned long   begin;
  22         unsigned long   flags;
  23 };
  24
  25 #define RATELIMIT_STATE_INIT_FLAGS(name, interval_init, burst_init, flags_init) { \
  26                 .lock           = __RAW_SPIN_LOCK_UNLOCKED(name.lock),            \
  27                 .interval       = interval_init,                                  \
  28                 .burst          = burst_init,                                     \
  29                 .flags          = flags_init,                                     \
  30         }
  31
  32 #define RATELIMIT_STATE_INIT(name, interval_init, burst_init) \
  33         RATELIMIT_STATE_INIT_FLAGS(name, interval_init, burst_init, 0)
  34
  35 #define RATELIMIT_STATE_INIT_DISABLED                                   \
  36         RATELIMIT_STATE_INIT(ratelimit_state, 0, DEFAULT_RATELIMIT_BURST)
  37
  38 #define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init)         \
  39                                                                         \
  40         struct ratelimit_state name =                                   \
  41                 RATELIMIT_STATE_INIT(name, interval_init, burst_init)   \
  42
  43 static inline void ratelimit_state_init(struct ratelimit_state *rs,
  44                                         int interval, int burst)
  45 {
  46         memset(rs, 0, sizeof(*rs));
  47
  48         raw_spin_lock_init(&rs->lock);
  49         rs->interval    = interval;
  50         rs->burst       = burst;
  51 }
  52
  53 static inline void ratelimit_default_init(struct ratelimit_state *rs)
  54 {
  55         return ratelimit_state_init(rs, DEFAULT_RATELIMIT_INTERVAL,
  56                                         DEFAULT_RATELIMIT_BURST);
  57 }
  58
  59 static inline void ratelimit_state_exit(struct ratelimit_state *rs)
  60 {
  61         if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE))
  62                 return;
  63
  64         if (rs->missed) {
  65                 pr_warn("%s: %d output lines suppressed due to ratelimiting\n",
  66                         current->comm, rs->missed);
  67                 rs->missed = 0;
  68         }
  69 }
  70
  71 static inline void
  72 ratelimit_set_flags(struct ratelimit_state *rs, unsigned long flags)
  73 {
  74         rs->flags = flags;
  75 }
  76
  77 extern struct ratelimit_state printk_ratelimit_state;
  78
  79 extern int ___ratelimit(struct ratelimit_state *rs, const char *func);
  80 #define __ratelimit(state) ___ratelimit(state, __func__)
  81
  82 #ifdef CONFIG_PRINTK
  83
  84 #define WARN_ON_RATELIMIT(condition, state)                     \
  85                 WARN_ON((condition) && __ratelimit(state))
  86
  87 #define WARN_RATELIMIT(condition, format, ...)                  \
  88 ({                                                              \
  89         static DEFINE_RATELIMIT_STATE(_rs,                      \
  90                                       DEFAULT_RATELIMIT_INTERVAL,       \
  91                                       DEFAULT_RATELIMIT_BURST); \
  92         int rtn = !!(condition);                                \
  93                                                                 \
  94         if (unlikely(rtn && __ratelimit(&_rs)))                 \
  95                 WARN(rtn, format, ##__VA_ARGS__);               \
  96                                                                 \
  97         rtn;                                                    \
  98 })
  99
 100 #else
 101
 102 #define WARN_ON_RATELIMIT(condition, state)                     \
 103         WARN_ON(condition)
 104
 105 #define WARN_RATELIMIT(condition, format, ...)                  \
 106 ({                                                              \
 107         int rtn = WARN(condition, format, ##__VA_ARGS__);       \
 108         rtn;                                                    \
 109 })
 110
 111 #endif
 112
 113 #endif /* _LINUX_RATELIMIT_H */