+++ /dev/null
-
-#include <pthread.h>
-#include <signal.h>
-#include <time.h>
-
-#include <linux/kernel.h>
-#include <linux/kthread.h>
-#include <linux/timer.h>
-
-/**
- * timespec_add_ns - Adds nanoseconds to a timespec
- * @a: pointer to timespec to be incremented
- * @ns: unsigned nanoseconds value to be added
- *
- * This must always be inlined because its used from the x86-64 vdso,
- * which cannot call other kernel functions.
- */
-static struct timespec timespec_add_ns(struct timespec a, u64 ns)
-{
- a.tv_nsec += ns;
- a.tv_sec += a.tv_nsec / NSEC_PER_SEC;
- a.tv_nsec %= NSEC_PER_SEC;
- return a;
-}
-
-#define DECLARE_HEAP(type) \
-struct { \
- size_t size, used; \
- type *data; \
-}
-
-#define heap_init(heap, _size) \
-({ \
- size_t _bytes; \
- (heap)->used = 0; \
- (heap)->size = (_size); \
- _bytes = (heap)->size * sizeof(*(heap)->data); \
- (heap)->data = malloc(_bytes); \
- (heap)->data; \
-})
-
-#define heap_free(heap) \
-do { \
- kvfree((heap)->data); \
- (heap)->data = NULL; \
-} while (0)
-
-#define heap_swap(h, i, j) swap((h)->data[i], (h)->data[j])
-
-#define heap_sift(h, i, cmp) \
-do { \
- size_t _r, _j = i; \
- \
- for (; _j * 2 + 1 < (h)->used; _j = _r) { \
- _r = _j * 2 + 1; \
- if (_r + 1 < (h)->used && \
- cmp((h)->data[_r], (h)->data[_r + 1])) \
- _r++; \
- \
- if (cmp((h)->data[_r], (h)->data[_j])) \
- break; \
- heap_swap(h, _r, _j); \
- } \
-} while (0)
-
-#define heap_sift_down(h, i, cmp) \
-do { \
- while (i) { \
- size_t p = (i - 1) / 2; \
- if (cmp((h)->data[i], (h)->data[p])) \
- break; \
- heap_swap(h, i, p); \
- i = p; \
- } \
-} while (0)
-
-#define heap_add(h, d, cmp) \
-({ \
- bool _r = !heap_full(h); \
- if (_r) { \
- size_t _i = (h)->used++; \
- (h)->data[_i] = d; \
- \
- heap_sift_down(h, _i, cmp); \
- heap_sift(h, _i, cmp); \
- } \
- _r; \
-})
-
-#define heap_del(h, i, cmp) \
-do { \
- size_t _i = (i); \
- \
- BUG_ON(_i >= (h)->used); \
- (h)->used--; \
- if ((_i) < (h)->used) { \
- heap_swap(h, _i, (h)->used); \
- heap_sift_down(h, _i, cmp); \
- heap_sift(h, _i, cmp); \
- } \
-} while (0)
-
-#define heap_pop(h, d, cmp) \
-({ \
- bool _r = (h)->used; \
- if (_r) { \
- (d) = (h)->data[0]; \
- heap_del(h, 0, cmp); \
- } \
- _r; \
-})
-
-#define heap_peek(h) ((h)->used ? &(h)->data[0] : NULL)
-#define heap_full(h) ((h)->used == (h)->size)
-#define heap_empty(h) ((h)->used == 0)
-
-#define heap_resort(heap, cmp) \
-do { \
- ssize_t _i; \
- for (_i = (ssize_t) (heap)->used / 2 - 1; _i >= 0; --_i) \
- heap_sift(heap, _i, cmp); \
-} while (0)
-
-struct pending_timer {
- struct timer_list *timer;
- unsigned long expires;
-};
-
-static inline bool pending_timer_cmp(struct pending_timer a,
- struct pending_timer b)
-{
- return a.expires < b.expires;
-}
-
-static DECLARE_HEAP(struct pending_timer) pending_timers;
-
-static pthread_mutex_t timer_lock = PTHREAD_MUTEX_INITIALIZER;
-static pthread_cond_t timer_cond = PTHREAD_COND_INITIALIZER;
-static pthread_cond_t timer_running_cond = PTHREAD_COND_INITIALIZER;
-static unsigned long timer_seq;
-
-static inline bool timer_running(void)
-{
- return timer_seq & 1;
-}
-
-static ssize_t timer_idx(struct timer_list *timer)
-{
- size_t i;
-
- for (i = 0; i < pending_timers.used; i++)
- if (pending_timers.data[i].timer == timer)
- return i;
-
- return -1;
-}
-
-int del_timer(struct timer_list *timer)
-{
- ssize_t idx;
-
- pthread_mutex_lock(&timer_lock);
- idx = timer_idx(timer);
- if (idx >= 0)
- heap_del(&pending_timers, idx, pending_timer_cmp);
-
- timer->pending = false;
- pthread_mutex_unlock(&timer_lock);
-
- return idx >= 0;
-}
-
-void flush_timers(void)
-{
- unsigned long seq;
-
- pthread_mutex_lock(&timer_lock);
- seq = timer_seq;
- while (timer_running() && seq == timer_seq)
- pthread_cond_wait(&timer_running_cond, &timer_lock);
-
- pthread_mutex_unlock(&timer_lock);
-}
-
-int del_timer_sync(struct timer_list *timer)
-{
- unsigned long seq;
- ssize_t idx;
-
- pthread_mutex_lock(&timer_lock);
- idx = timer_idx(timer);
- if (idx >= 0)
- heap_del(&pending_timers, idx, pending_timer_cmp);
-
- timer->pending = false;
-
- seq = timer_seq;
- while (timer_running() && seq == timer_seq)
- pthread_cond_wait(&timer_running_cond, &timer_lock);
- pthread_mutex_unlock(&timer_lock);
-
- return idx >= 0;
-}
-
-int mod_timer(struct timer_list *timer, unsigned long expires)
-{
- ssize_t idx;
-
- pthread_mutex_lock(&timer_lock);
- timer->expires = expires;
- timer->pending = true;
- idx = timer_idx(timer);
-
- if (idx >= 0 &&
- pending_timers.data[idx].expires == expires)
- goto out;
-
- if (idx >= 0) {
- pending_timers.data[idx].expires = expires;
-
- heap_sift_down(&pending_timers, idx, pending_timer_cmp);
- heap_sift(&pending_timers, idx, pending_timer_cmp);
- } else {
- if (heap_full(&pending_timers)) {
- pending_timers.size *= 2;
- pending_timers.data =
- realloc(pending_timers.data,
- pending_timers.size *
- sizeof(struct pending_timer));
-
- BUG_ON(!pending_timers.data);
- }
-
- heap_add(&pending_timers,
- ((struct pending_timer) {
- .timer = timer,
- .expires = expires,
- }),
- pending_timer_cmp);
- }
-
- pthread_cond_signal(&timer_cond);
-out:
- pthread_mutex_unlock(&timer_lock);
-
- return idx >= 0;
-}
-
-static bool timer_thread_stop = false;
-
-static int timer_thread(void *arg)
-{
- struct pending_timer *p;
- struct timespec ts;
- unsigned long now;
- int ret;
-
- pthread_mutex_lock(&timer_lock);
-
- while (!timer_thread_stop) {
- now = jiffies;
- p = heap_peek(&pending_timers);
-
- if (!p) {
- pthread_cond_wait(&timer_cond, &timer_lock);
- continue;
- }
-
- if (time_after_eq(now, p->expires)) {
- struct timer_list *timer = p->timer;
-
- heap_del(&pending_timers, 0, pending_timer_cmp);
- BUG_ON(!timer_pending(timer));
- timer->pending = false;
-
- timer_seq++;
- BUG_ON(!timer_running());
-
- pthread_mutex_unlock(&timer_lock);
- timer->function(timer);
- pthread_mutex_lock(&timer_lock);
-
- timer_seq++;
- pthread_cond_broadcast(&timer_running_cond);
- continue;
- }
-
-
- ret = clock_gettime(CLOCK_REALTIME, &ts);
- BUG_ON(ret);
-
- ts = timespec_add_ns(ts, jiffies_to_nsecs(p->expires - now));
-
- pthread_cond_timedwait(&timer_cond, &timer_lock, &ts);
- }
-
- pthread_mutex_unlock(&timer_lock);
-
- return 0;
-}
-
-struct task_struct *timer_task;
-
-__attribute__((constructor(103)))
-static void timers_init(void)
-{
- heap_init(&pending_timers, 64);
- BUG_ON(!pending_timers.data);
-
- timer_task = kthread_run(timer_thread, NULL, "timers");
- BUG_ON(IS_ERR(timer_task));
-}
-
-__attribute__((destructor(103)))
-static void timers_cleanup(void)
-{
- get_task_struct(timer_task);
-
- pthread_mutex_lock(&timer_lock);
- timer_thread_stop = true;
- pthread_cond_signal(&timer_cond);
- pthread_mutex_unlock(&timer_lock);
-
- int ret = kthread_stop(timer_task);
- BUG_ON(ret);
-
- put_task_struct(timer_task);
- timer_task = NULL;
-}
projects / bcachefs-tools-debian / blobdiff