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(name, interval_init, burst_init) {         \
  26                 .lock           = __RAW_SPIN_LOCK_UNLOCKED(name.lock),  \
  27                 .interval       = interval_init,                        \
  28                 .burst          = burst_init,                           \
  29         }
  30
  31 #define RATELIMIT_STATE_INIT_DISABLED                                   \
  32         RATELIMIT_STATE_INIT(ratelimit_state, 0, DEFAULT_RATELIMIT_BURST)
  33
  34 #define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init)         \
  35                                                                         \
  36         struct ratelimit_state name =                                   \
  37                 RATELIMIT_STATE_INIT(name, interval_init, burst_init)   \
  38
  39 static inline void ratelimit_state_init(struct ratelimit_state *rs,
  40                                         int interval, int burst)
  41 {
  42         memset(rs, 0, sizeof(*rs));
  43
  44         raw_spin_lock_init(&rs->lock);
  45         rs->interval    = interval;
  46         rs->burst       = burst;
  47 }
  48
  49 static inline void ratelimit_default_init(struct ratelimit_state *rs)
  50 {
  51         return ratelimit_state_init(rs, DEFAULT_RATELIMIT_INTERVAL,
  52                                         DEFAULT_RATELIMIT_BURST);
  53 }
  54
  55 static inline void ratelimit_state_exit(struct ratelimit_state *rs)
  56 {
  57         if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE))
  58                 return;
  59
  60         if (rs->missed) {
  61                 pr_warn("%s: %d output lines suppressed due to ratelimiting\n",
  62                         current->comm, rs->missed);
  63                 rs->missed = 0;
  64         }
  65 }
  66
  67 static inline void
  68 ratelimit_set_flags(struct ratelimit_state *rs, unsigned long flags)
  69 {
  70         rs->flags = flags;
  71 }
  72
  73 extern struct ratelimit_state printk_ratelimit_state;
  74
  75 extern int ___ratelimit(struct ratelimit_state *rs, const char *func);
  76 #define __ratelimit(state) ___ratelimit(state, __func__)
  77
  78 #ifdef CONFIG_PRINTK
  79
  80 #define WARN_ON_RATELIMIT(condition, state)                     \
  81                 WARN_ON((condition) && __ratelimit(state))
  82
  83 #define WARN_RATELIMIT(condition, format, ...)                  \
  84 ({                                                              \
  85         static DEFINE_RATELIMIT_STATE(_rs,                      \
  86                                       DEFAULT_RATELIMIT_INTERVAL,       \
  87                                       DEFAULT_RATELIMIT_BURST); \
  88         int rtn = !!(condition);                                \
  89                                                                 \
  90         if (unlikely(rtn && __ratelimit(&_rs)))                 \
  91                 WARN(rtn, format, ##__VA_ARGS__);               \
  92                                                                 \
  93         rtn;                                                    \
  94 })
  95
  96 #else
  97
  98 #define WARN_ON_RATELIMIT(condition, state)                     \
  99         WARN_ON(condition)
 100
 101 #define WARN_RATELIMIT(condition, format, ...)                  \
 102 ({                                                              \
 103         int rtn = WARN(condition, format, ##__VA_ARGS__);       \
 104         rtn;                                                    \
 105 })
 106
 107 #endif
 108
 109 #endif /* _LINUX_RATELIMIT_H */