ratelimit.h

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#ifndef __LINUX_RATELIMIT_H__
#define __LINUX_RATELIMIT_H__
 
/*
 * DCL <linux/ratelimit.h> -- error printing that does not repeat itself.
 *
 * The staged set needs the *_ratelimited spellings (serial_core.c:1014 warns
 * once per process about deprecated ASYNC_ flags; tty_io.c does the same for
 * legacy TIOC* ioctls), and it includes this header to get them.
 *
 * DCL has no ratelimit_state worth the name -- there is no jiffies-driven
 * suppression to borrow cheaply, and a suppressed warning on a single-user
 * console is a warning nobody was going to act on anyway. So the macros pass
 * straight through to their pr_* counterparts. The result is *louder* than
 * mainline, never quieter, and that is the direction to be wrong in: a
 * deprecation warning printed every time is noise; one silently dropped
 * because a rate limiter ticked wrong is a lost diagnostic.
 *
 * struct ratelimit_state and __ratelimit() exist so code that builds a limiter
 * explicitly still compiles; __ratelimit() always answers 1 (proceed).
 */
 
#include <linux/printk.h>
 
/*
 * DCL delta: mainline's defaults, added with the virtio-gpu port --
 * virtgpu_vq.c:254's DRM_ERROR_RATELIMITED expands DEFINE_RATELIMIT_STATE
 * with these. The value is inert here (__ratelimit() always proceeds), so
 * the interval is written out rather than left as `5 * HZ`: this header
 * cannot count on <linux/timer.h> being in scope at every use site, and 1250
 * is five seconds at DCL's HZ (250, linux/timer.h:57) if the limiter ever
 * grows teeth.
 */
#define DEFAULT_RATELIMIT_INTERVAL  1250
#define DEFAULT_RATELIMIT_BURST     10
 
struct ratelimit_state {
    int interval;
    int burst;
    int printed;
    int missed;
    unsigned long begin;
};
 
#define RATELIMIT_DISABLED (struct ratelimit_state){ .interval = 0 }
 
static inline int __ratelimit(struct ratelimit_state* rs)
{
    (void)rs;
    return 1;
}
 
#define ratelimit_state_init(rs, b, i) \
    do { (void)(rs); (void)(b); (void)(i); } while (0)
 
#define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init) \
    struct ratelimit_state name = { (interval_init), (burst_init), 0, 0, 0 }
 
#define pr_emerg_ratelimited(fmt, ...)   pr_emerg(fmt, ##__VA_ARGS__)
#define pr_alert_ratelimited(fmt, ...)   pr_alert(fmt, ##__VA_ARGS__)
#define pr_crit_ratelimited(fmt, ...)    pr_crit(fmt, ##__VA_ARGS__)
#define pr_err_ratelimited(fmt, ...)     pr_err(fmt, ##__VA_ARGS__)
#define pr_warn_ratelimited(fmt, ...)    pr_warn(fmt, ##__VA_ARGS__)
#define pr_notice_ratelimited(fmt, ...)  pr_notice(fmt, ##__VA_ARGS__)
#define pr_info_ratelimited(fmt, ...)    pr_info(fmt, ##__VA_ARGS__)
#define pr_debug_ratelimited(fmt, ...)   pr_debug(fmt, ##__VA_ARGS__)
 
#define printk_ratelimited(fmt, ...)     printk(fmt, ##__VA_ARGS__)
 
#endif /* __LINUX_RATELIMIT_H__ */