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diff --git a/sys/kern/kern_umtx.c b/sys/kern/kern_umtx.c
--- a/sys/kern/kern_umtx.c
+++ b/sys/kern/kern_umtx.c
@@ -90,6 +90,17 @@
#endif
#define UMTXQ_LOCKED_ASSERT(uc) mtx_assert(&(uc)->uc_lock, MA_OWNED)
+#ifdef INVARIANTS
+#define UMTXQ_ASSERT_LOCKED_BUSY(key) do { \
+ struct umtxq_chain *uc; \
+ \
+ uc = umtxq_getchain(key); \
+ mtx_assert(&uc->uc_lock, MA_OWNED); \
+ KASSERT(uc->uc_busy != 0, ("umtx chain is not busy")); \
+} while (0)
+#else
+#define UMTXQ_ASSERT_LOCKED_BUSY(key) do {} while (0)
+#endif
/*
* Don't propagate time-sharing priority, there is a security reason,
@@ -2077,6 +2088,73 @@
TAILQ_INSERT_TAIL(&uc->uc_pi_list, pi, pi_hashlink);
}
+/*
+ * Drop a PI mutex and wakeup a top waiter.
+ */
+int
+umtx_pi_drop(struct thread *td, struct umtx_key *key, bool rb, int *count)
+{
+ struct umtx_q *uq_first, *uq_first2, *uq_me;
+ struct umtx_pi *pi, *pi2;
+ int pri;
+
+ UMTXQ_ASSERT_LOCKED_BUSY(key);
+ *count = umtxq_count_pi(key, &uq_first);
+ if (uq_first != NULL) {
+ mtx_lock(&umtx_lock);
+ pi = uq_first->uq_pi_blocked;
+ KASSERT(pi != NULL, ("pi == NULL?"));
+ if (pi->pi_owner != td && !(rb && pi->pi_owner == NULL)) {
+ mtx_unlock(&umtx_lock);
+ /* userland messed the mutex */
+ return (EPERM);
+ }
+ uq_me = td->td_umtxq;
+ if (pi->pi_owner == td)
+ umtx_pi_disown(pi);
+ /* get highest priority thread which is still sleeping. */
+ uq_first = TAILQ_FIRST(&pi->pi_blocked);
+ while (uq_first != NULL &&
+ (uq_first->uq_flags & UQF_UMTXQ) == 0) {
+ uq_first = TAILQ_NEXT(uq_first, uq_lockq);
+ }
+ pri = PRI_MAX;
+ TAILQ_FOREACH(pi2, &uq_me->uq_pi_contested, pi_link) {
+ uq_first2 = TAILQ_FIRST(&pi2->pi_blocked);
+ if (uq_first2 != NULL) {
+ if (pri > UPRI(uq_first2->uq_thread))
+ pri = UPRI(uq_first2->uq_thread);
+ }
+ }
+ thread_lock(td);
+ sched_lend_user_prio(td, pri);
+ thread_unlock(td);
+ mtx_unlock(&umtx_lock);
+ if (uq_first)
+ umtxq_signal_thread(uq_first);
+ } else {
+ pi = umtx_pi_lookup(key);
+ /*
+ * A umtx_pi can exist if a signal or timeout removed the
+ * last waiter from the umtxq, but there is still
+ * a thread in do_lock_pi() holding the umtx_pi.
+ */
+ if (pi != NULL) {
+ /*
+ * The umtx_pi can be unowned, such as when a thread
+ * has just entered do_lock_pi(), allocated the
+ * umtx_pi, and unlocked the umtxq.
+ * If the current thread owns it, it must disown it.
+ */
+ mtx_lock(&umtx_lock);
+ if (pi->pi_owner == td)
+ umtx_pi_disown(pi);
+ mtx_unlock(&umtx_lock);
+ }
+ }
+ return (0);
+}
+
/*
* Lock a PI mutex.
*/
@@ -2287,10 +2365,8 @@
do_unlock_pi(struct thread *td, struct umutex *m, uint32_t flags, bool rb)
{
struct umtx_key key;
- struct umtx_q *uq_first, *uq_first2, *uq_me;
- struct umtx_pi *pi, *pi2;
uint32_t id, new_owner, old, owner;
- int count, error, pri;
+ int count, error;
id = td->td_tid;
@@ -2331,61 +2407,13 @@
umtxq_lock(&key);
umtxq_busy(&key);
- count = umtxq_count_pi(&key, &uq_first);
- if (uq_first != NULL) {
- mtx_lock(&umtx_lock);
- pi = uq_first->uq_pi_blocked;
- KASSERT(pi != NULL, ("pi == NULL?"));
- if (pi->pi_owner != td && !(rb && pi->pi_owner == NULL)) {
- mtx_unlock(&umtx_lock);
- umtxq_unbusy(&key);
- umtxq_unlock(&key);
- umtx_key_release(&key);
- /* userland messed the mutex */
- return (EPERM);
- }
- uq_me = td->td_umtxq;
- if (pi->pi_owner == td)
- umtx_pi_disown(pi);
- /* get highest priority thread which is still sleeping. */
- uq_first = TAILQ_FIRST(&pi->pi_blocked);
- while (uq_first != NULL &&
- (uq_first->uq_flags & UQF_UMTXQ) == 0) {
- uq_first = TAILQ_NEXT(uq_first, uq_lockq);
- }
- pri = PRI_MAX;
- TAILQ_FOREACH(pi2, &uq_me->uq_pi_contested, pi_link) {
- uq_first2 = TAILQ_FIRST(&pi2->pi_blocked);
- if (uq_first2 != NULL) {
- if (pri > UPRI(uq_first2->uq_thread))
- pri = UPRI(uq_first2->uq_thread);
- }
- }
- thread_lock(td);
- sched_lend_user_prio(td, pri);
- thread_unlock(td);
- mtx_unlock(&umtx_lock);
- if (uq_first)
- umtxq_signal_thread(uq_first);
- } else {
- pi = umtx_pi_lookup(&key);
- /*
- * A umtx_pi can exist if a signal or timeout removed the
- * last waiter from the umtxq, but there is still
- * a thread in do_lock_pi() holding the umtx_pi.
- */
- if (pi != NULL) {
- /*
- * The umtx_pi can be unowned, such as when a thread
- * has just entered do_lock_pi(), allocated the
- * umtx_pi, and unlocked the umtxq.
- * If the current thread owns it, it must disown it.
- */
- mtx_lock(&umtx_lock);
- if (pi->pi_owner == td)
- umtx_pi_disown(pi);
- mtx_unlock(&umtx_lock);
- }
+ error = umtx_pi_drop(td, &key, rb, &count);
+ if (error != 0) {
+ umtxq_unbusy(&key);
+ umtxq_unlock(&key);
+ umtx_key_release(&key);
+ /* userland messed the mutex */
+ return (error);
}
umtxq_unlock(&key);
diff --git a/sys/sys/umtxvar.h b/sys/sys/umtxvar.h
--- a/sys/sys/umtxvar.h
+++ b/sys/sys/umtxvar.h
@@ -222,6 +222,7 @@
void umtx_pi_adjust(struct thread *, u_char);
struct umtx_pi *umtx_pi_alloc(int);
int umtx_pi_claim(struct umtx_pi *, struct thread *);
+int umtx_pi_drop(struct thread *, struct umtx_key *, bool, int *);
void umtx_pi_free(struct umtx_pi *);
void umtx_pi_insert(struct umtx_pi *);
struct umtx_pi *umtx_pi_lookup(struct umtx_key *);

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