diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index 07a2db7c8396..f3461a4e6bdc 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -136,7 +136,7 @@ struct signal_struct { #ifdef CONFIG_POSIX_TIMERS /* POSIX.1b Interval Timers */ - unsigned int next_posix_timer_id; + int posix_timer_id; struct list_head posix_timers; /* ITIMER_REAL timer for the process */ diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c index 2d6cf93ca370..ed3c4a954398 100644 --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -140,30 +140,25 @@ static struct k_itimer *posix_timer_by_id(timer_t id) static int posix_timer_add(struct k_itimer *timer) { struct signal_struct *sig = current->signal; + int first_free_id = sig->posix_timer_id; struct hlist_head *head; - unsigned int cnt, id; + int ret = -ENOENT; - /* - * FIXME: Replace this by a per signal struct xarray once there is - * a plan to handle the resulting CRIU regression gracefully. - */ - for (cnt = 0; cnt <= INT_MAX; cnt++) { + do { spin_lock(&hash_lock); - id = sig->next_posix_timer_id; - - /* Write the next ID back. Clamp it to the positive space */ - sig->next_posix_timer_id = (id + 1) & INT_MAX; - - head = &posix_timers_hashtable[hash(sig, id)]; - if (!__posix_timers_find(head, sig, id)) { + head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)]; + if (!__posix_timers_find(head, sig, sig->posix_timer_id)) { hlist_add_head_rcu(&timer->t_hash, head); - spin_unlock(&hash_lock); - return id; + ret = sig->posix_timer_id; } + if (++sig->posix_timer_id < 0) + sig->posix_timer_id = 0; + if ((sig->posix_timer_id == first_free_id) && (ret == -ENOENT)) + /* Loop over all possible ids completed */ + ret = -EAGAIN; spin_unlock(&hash_lock); - } - /* POSIX return code when no timer ID could be allocated */ - return -EAGAIN; + } while (ret == -ENOENT); + return ret; } static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)