diff options
Diffstat (limited to 'sys/kern/kern_synch.c')
| -rw-r--r-- | sys/kern/kern_synch.c | 104 |
1 files changed, 73 insertions, 31 deletions
diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c index da5b4e9b34e..02c733ad8f1 100644 --- a/sys/kern/kern_synch.c +++ b/sys/kern/kern_synch.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kern_synch.c,v 1.158 2020/01/16 16:35:04 mpi Exp $ */ +/* $OpenBSD: kern_synch.c,v 1.159 2020/01/21 15:20:47 visa Exp $ */ /* $NetBSD: kern_synch.c,v 1.37 1996/04/22 01:38:37 christos Exp $ */ /* @@ -634,7 +634,14 @@ thrsleep_unlock(void *lock) return copyout(&unlocked, atomiclock, sizeof(unlocked)); } -static int globalsleepaddr; +struct tslpentry { + TAILQ_ENTRY(tslpentry) tslp_link; + long tslp_ident; +}; + +/* thrsleep queue shared between processes */ +static struct tslpqueue thrsleep_queue = TAILQ_HEAD_INITIALIZER(thrsleep_queue); +static struct rwlock thrsleep_lock = RWLOCK_INITIALIZER("thrsleeplk"); int thrsleep(struct proc *p, struct sys___thrsleep_args *v) @@ -647,10 +654,13 @@ thrsleep(struct proc *p, struct sys___thrsleep_args *v) syscallarg(const int *) abort; } */ *uap = v; long ident = (long)SCARG(uap, ident); + struct tslpentry entry; + struct tslpqueue *queue; + struct rwlock *qlock; struct timespec *tsp = (struct timespec *)SCARG(uap, tp); void *lock = SCARG(uap, lock); uint64_t nsecs = INFSLP; - int abort, error; + int abort = 0, error; clockid_t clock_id = SCARG(uap, clock_id); if (ident == 0) @@ -676,32 +686,41 @@ thrsleep(struct proc *p, struct sys___thrsleep_args *v) nsecs = TIMESPEC_TO_NSEC(tsp); } - p->p_thrslpid = ident; + if (ident == -1) { + queue = &thrsleep_queue; + qlock = &thrsleep_lock; + } else { + queue = &p->p_p->ps_tslpqueue; + qlock = &p->p_p->ps_lock; + } - if ((error = thrsleep_unlock(lock))) - goto out; + /* Interlock with wakeup. */ + entry.tslp_ident = ident; + rw_enter_write(qlock); + TAILQ_INSERT_TAIL(queue, &entry, tslp_link); + rw_exit_write(qlock); - if (SCARG(uap, abort) != NULL) { - if ((error = copyin(SCARG(uap, abort), &abort, - sizeof(abort))) != 0) - goto out; - if (abort) { - error = EINTR; - goto out; - } - } + error = thrsleep_unlock(lock); - if (p->p_thrslpid == 0) - error = 0; - else { - void *sleepaddr = &p->p_thrslpid; - if (ident == -1) - sleepaddr = &globalsleepaddr; - error = tsleep_nsec(sleepaddr, PWAIT|PCATCH, "thrsleep", nsecs); + if (error == 0 && SCARG(uap, abort) != NULL) + error = copyin(SCARG(uap, abort), &abort, sizeof(abort)); + + rw_enter_write(qlock); + if (error != 0) + goto out; + if (abort != 0) { + error = EINTR; + goto out; + } + if (entry.tslp_ident != 0) { + error = rwsleep_nsec(&entry, qlock, PWAIT|PCATCH, "thrsleep", + nsecs); } out: - p->p_thrslpid = 0; + if (entry.tslp_ident != 0) + TAILQ_REMOVE(queue, &entry, tslp_link); + rw_exit_write(qlock); if (error == ERESTART) error = ECANCELED; @@ -746,25 +765,48 @@ sys___thrwakeup(struct proc *p, void *v, register_t *retval) syscallarg(const volatile void *) ident; syscallarg(int) n; } */ *uap = v; + struct tslpentry *entry, *tmp; + struct tslpqueue *queue; + struct rwlock *qlock; long ident = (long)SCARG(uap, ident); int n = SCARG(uap, n); - struct proc *q; int found = 0; if (ident == 0) *retval = EINVAL; - else if (ident == -1) - wakeup(&globalsleepaddr); else { - TAILQ_FOREACH(q, &p->p_p->ps_threads, p_thr_link) { - if (q->p_thrslpid == ident) { - wakeup_one(&q->p_thrslpid); - q->p_thrslpid = 0; + if (ident == -1) { + queue = &thrsleep_queue; + qlock = &thrsleep_lock; + /* + * Wake up all waiters with ident -1. This is needed + * because ident -1 can be shared by multiple userspace + * lock state machines concurrently. The implementation + * has no way to direct the wakeup to a particular + * state machine. + */ + n = 0; + } else { + queue = &p->p_p->ps_tslpqueue; + qlock = &p->p_p->ps_lock; + } + + rw_enter_write(qlock); + TAILQ_FOREACH_SAFE(entry, queue, tslp_link, tmp) { + if (entry->tslp_ident == ident) { + TAILQ_REMOVE(queue, entry, tslp_link); + entry->tslp_ident = 0; + wakeup_one(entry); if (++found == n) break; } } - *retval = found ? 0 : ESRCH; + rw_exit_write(qlock); + + if (ident == -1) + *retval = 0; + else + *retval = found ? 0 : ESRCH; } return (0); |