include/linux/ratelimit.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_RATELIMIT_H
   3 #define _LINUX_RATELIMIT_H
   4
   5 #include <linux/param.h>
   6 #include <linux/sched.h>
   7 #include <linux/spinlock.h>
   8
   9 #define DEFAULT_RATELIMIT_INTERVAL      (5 * HZ)
  10 #define DEFAULT_RATELIMIT_BURST         10
  11
  12 /* issue num suppressed message on exit */
  13 #define RATELIMIT_MSG_ON_RELEASE        BIT(0)
  14
  15 struct ratelimit_state {
  16         raw_spinlock_t  lock;           /* protect the state */
  17
  18         int             interval;
  19         int             burst;
  20         int             printed;
  21         int             missed;
  22         unsigned long   begin;
  23         unsigned long   flags;
  24 };
  25
  26 #define RATELIMIT_STATE_INIT(name, interval_init, burst_init) {         \
  27                 .lock           = __RAW_SPIN_LOCK_UNLOCKED(name.lock),  \
  28                 .interval       = interval_init,                        \
  29                 .burst          = burst_init,                           \
  30         }
  31
  32 #define RATELIMIT_STATE_INIT_DISABLED                                   \
  33         RATELIMIT_STATE_INIT(ratelimit_state, 0, DEFAULT_RATELIMIT_BURST)
  34
  35 #define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init)         \
  36                                                                         \
  37         struct ratelimit_state name =                                   \
  38                 RATELIMIT_STATE_INIT(name, interval_init, burst_init)   \
  39
  40 static inline void ratelimit_state_init(struct ratelimit_state *rs,
  41                                         int interval, int burst)
  42 {
  43         memset(rs, 0, sizeof(*rs));
  44
  45         raw_spin_lock_init(&rs->lock);
  46         rs->interval    = interval;
  47         rs->burst       = burst;
  48 }
  49
  50 static inline void ratelimit_default_init(struct ratelimit_state *rs)
  51 {
  52         return ratelimit_state_init(rs, DEFAULT_RATELIMIT_INTERVAL,
  53                                         DEFAULT_RATELIMIT_BURST);
  54 }
  55
  56 static inline void ratelimit_state_exit(struct ratelimit_state *rs)
  57 {
  58         if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE))
  59                 return;
  60
  61         if (rs->missed) {
  62                 pr_warn("%s: %d output lines suppressed due to ratelimiting\n",
  63                         current->comm, rs->missed);
  64                 rs->missed = 0;
  65         }
  66 }
  67
  68 static inline void
  69 ratelimit_set_flags(struct ratelimit_state *rs, unsigned long flags)
  70 {
  71         rs->flags = flags;
  72 }
  73
  74 extern struct ratelimit_state printk_ratelimit_state;
  75
  76 extern int ___ratelimit(struct ratelimit_state *rs, const char *func);
  77 #define __ratelimit(state) ___ratelimit(state, __func__)
  78
  79 #ifdef CONFIG_PRINTK
  80
  81 #define WARN_ON_RATELIMIT(condition, state)     ({              \
  82         bool __rtn_cond = !!(condition);                        \
  83         WARN_ON(__rtn_cond && __ratelimit(state));              \
  84         __rtn_cond;                                             \
  85 })
  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 */