/*
* Routine: _wait_queue_select64_one
* Purpose:
* Select the best thread off a wait queue that meet the
* supplied criteria.
* Conditions:
* at splsched
* wait queue locked
* possibly recursive
* Returns:
* a locked thread - if one found
* Note:
* This is where the sync policy of the wait queue comes
* into effect. For now, we just assume FIFO.
*/
static thread_t
_wait_queue_select64_one(
wait_queue_t wq,
event64_t event)
{
wait_queue_element_t wq_element;
wait_queue_element_t wqe_next;
thread_t t = THREAD_NULL;
queue_t q;
assert(wq->wq_fifo);
q = &wq->wq_queue;
wq_element = (wait_queue_element_t) queue_first(q);
while (!queue_end(q, (queue_entry_t)wq_element)) {
WAIT_QUEUE_ELEMENT_CHECK(wq, wq_element);
wqe_next = (wait_queue_element_t)
queue_next((queue_t) wq_element);
/*
* We may have to recurse if this is a compound wait queue.
*/
if (wq_element->wqe_type == WAIT_QUEUE_LINK) {
wait_queue_link_t wql = (wait_queue_link_t)wq_element;
wait_queue_t set_queue;
/*
* We have to check the set wait queue.
*/
set_queue = (wait_queue_t)wql->wql_setqueue;
wait_queue_lock(set_queue);
if (! wait_queue_empty(set_queue)) {
t = _wait_queue_select64_one(set_queue, event);
}
wait_queue_unlock(set_queue);
if (t != THREAD_NULL)
return t;
} else {
/*
* Otherwise, its a thread. If it is waiting on
* the event we are posting to this queue, pull
* it off the queue and stick it in out wake_queue.
*/
thread_t t = (thread_t)wq_element;
if (t->wait_event == event) {
thread_lock(t);
remqueue(q, (queue_entry_t) t);
t->wait_queue = WAIT_QUEUE_NULL;
t->wait_event = NO_EVENT64;
t->at_safe_point = FALSE;
return t; /* still locked */
}
}
wq_element = wqe_next;
}
return THREAD_NULL;
}
/*
* Routine: wait_queue_member_locked
* Purpose:
* Indicate if this set queue is a member of the queue
* Conditions:
* The wait queue is locked
* The set queue is just that, a set queue
*/
static boolean_t
wait_queue_member_locked(
wait_queue_t wq,
wait_queue_set_t wq_set)
{
wait_queue_element_t wq_element;
queue_t q;
assert(wait_queue_held(wq));
assert(wait_queue_is_set(wq_set));
q = &wq->wq_queue;
wq_element = (wait_queue_element_t) queue_first(q);
while (!queue_end(q, (queue_entry_t)wq_element)) {
WAIT_QUEUE_ELEMENT_CHECK(wq, wq_element);
if ((wq_element->wqe_type == WAIT_QUEUE_LINK) ||
(wq_element->wqe_type == WAIT_QUEUE_LINK_NOALLOC)) {
wait_queue_link_t wql = (wait_queue_link_t)wq_element;
if (wql->wql_setqueue == wq_set)
return TRUE;
}
wq_element = (wait_queue_element_t)
queue_next((queue_t) wq_element);
}
return FALSE;
}
/*
* Routine: wait_queue_link_internal
* Purpose:
* Insert a set wait queue into a wait queue. This
* requires us to link the two together using a wait_queue_link
* structure that was provided.
* Conditions:
* The wait queue being inserted must be inited as a set queue
* The wait_queue_link structure must already be properly typed
*/
static
kern_return_t
wait_queue_link_internal(
wait_queue_t wq,
wait_queue_set_t wq_set,
wait_queue_link_t wql)
{
wait_queue_element_t wq_element;
queue_t q;
spl_t s;
if (!wait_queue_is_valid(wq) || !wait_queue_is_set(wq_set))
return KERN_INVALID_ARGUMENT;
/*
* There are probably fewer threads and sets associated with
* the wait queue than there are wait queues associated with
* the set. So let's validate it that way.
*/
s = splsched();
wait_queue_lock(wq);
q = &wq->wq_queue;
wq_element = (wait_queue_element_t) queue_first(q);
while (!queue_end(q, (queue_entry_t)wq_element)) {
WAIT_QUEUE_ELEMENT_CHECK(wq, wq_element);
if ((wq_element->wqe_type == WAIT_QUEUE_LINK ||
wq_element->wqe_type == WAIT_QUEUE_LINK_NOALLOC) &&
((wait_queue_link_t)wq_element)->wql_setqueue == wq_set) {
wait_queue_unlock(wq);
splx(s);
return KERN_ALREADY_IN_SET;
}
wq_element = (wait_queue_element_t)
queue_next((queue_t) wq_element);
}
/*
* Not already a member, so we can add it.
*/
wqs_lock(wq_set);
WAIT_QUEUE_SET_CHECK(wq_set);
assert(wql->wql_type == WAIT_QUEUE_LINK ||
wql->wql_type == WAIT_QUEUE_LINK_NOALLOC);
wql->wql_queue = wq;
wql_clear_prepost(wql);
queue_enter(&wq->wq_queue, wql, wait_queue_link_t, wql_links);
wql->wql_setqueue = wq_set;
queue_enter(&wq_set->wqs_setlinks, wql, wait_queue_link_t, wql_setlinks);
wqs_unlock(wq_set);
wait_queue_unlock(wq);
splx(s);
return KERN_SUCCESS;
}
kern_return_t
wait_queue_unlink_all(
wait_queue_t wq)
{
wait_queue_element_t wq_element;
wait_queue_element_t wq_next_element;
wait_queue_set_t wq_set;
wait_queue_link_t wql;
queue_head_t links_queue_head;
queue_t links = &links_queue_head;
queue_t q;
spl_t s;
if (!wait_queue_is_valid(wq)) {
return KERN_INVALID_ARGUMENT;
}
queue_init(links);
s = splsched();
wait_queue_lock(wq);
q = &wq->wq_queue;
wq_element = (wait_queue_element_t) queue_first(q);
while (!queue_end(q, (queue_entry_t)wq_element)) {
boolean_t alloced;
WAIT_QUEUE_ELEMENT_CHECK(wq, wq_element);
wq_next_element = (wait_queue_element_t)
queue_next((queue_t) wq_element);
alloced = (wq_element->wqe_type == WAIT_QUEUE_LINK);
if (alloced || wq_element->wqe_type == WAIT_QUEUE_LINK_NOALLOC) {
wql = (wait_queue_link_t)wq_element;
wq_set = wql->wql_setqueue;
wqs_lock(wq_set);
wait_queue_unlink_locked(wq, wq_set, wql);
wqs_unlock(wq_set);
if (alloced)
enqueue(links, &wql->wql_links);
}
wq_element = wq_next_element;
}
wait_queue_unlock(wq);
splx(s);
while(!queue_empty(links)) {
wql = (wait_queue_link_t) dequeue(links);
zfree(_wait_queue_link_zone, wql);
}
return(KERN_SUCCESS);
}
/*
* Routine: wait_queue_select64_thread
* Purpose:
* Look for a thread and remove it from the queues, if
* (and only if) the thread is waiting on the supplied
* <wait_queue, event> pair.
* Conditions:
* at splsched
* wait queue locked
* possibly recursive
* Returns:
* KERN_NOT_WAITING: Thread is not waiting here.
* KERN_SUCCESS: It was, and is now removed (returned locked)
*/
static kern_return_t
_wait_queue_select64_thread(
wait_queue_t wq,
event64_t event,
thread_t thread)
{
wait_queue_element_t wq_element;
wait_queue_element_t wqe_next;
kern_return_t res = KERN_NOT_WAITING;
queue_t q = &wq->wq_queue;
thread_lock(thread);
if ((thread->wait_queue == wq) && (thread->wait_event == event)) {
remqueue((queue_entry_t) thread);
thread->at_safe_point = FALSE;
thread->wait_event = NO_EVENT64;
thread->wait_queue = WAIT_QUEUE_NULL;
/* thread still locked */
return KERN_SUCCESS;
}
thread_unlock(thread);
/*
* The wait_queue associated with the thread may be one of this
* wait queue's sets. Go see. If so, removing it from
* there is like removing it from here.
*/
wq_element = (wait_queue_element_t) queue_first(q);
while (!queue_end(q, (queue_entry_t)wq_element)) {
WAIT_QUEUE_ELEMENT_CHECK(wq, wq_element);
wqe_next = (wait_queue_element_t)
queue_next((queue_t) wq_element);
if (wq_element->wqe_type == WAIT_QUEUE_LINK ||
wq_element->wqe_type == WAIT_QUEUE_LINK_NOALLOC) {
wait_queue_link_t wql = (wait_queue_link_t)wq_element;
wait_queue_set_t set_queue = wql->wql_setqueue;
wqs_lock(set_queue);
if (! wait_queue_empty(&set_queue->wqs_wait_queue)) {
res = _wait_queue_select64_thread(&set_queue->wqs_wait_queue,
event,
thread);
}
wqs_unlock(set_queue);
if (res == KERN_SUCCESS)
return KERN_SUCCESS;
}
wq_element = wqe_next;
}
return res;
}
kern_return_t
wait_queue_unlink_all(
wait_queue_t wq)
{
wait_queue_element_t wq_element;
wait_queue_element_t wq_next_element;
wait_queue_set_t wq_set;
wait_queue_link_t wql;
queue_head_t links_queue_head;
queue_t links = &links_queue_head;
queue_t q;
spl_t s;
if (!wait_queue_is_queue(wq)) {
return KERN_INVALID_ARGUMENT;
}
queue_init(links);
s = splsched();
wait_queue_lock(wq);
q = &wq->wq_queue;
wq_element = (wait_queue_element_t) queue_first(q);
while (!queue_end(q, (queue_entry_t)wq_element)) {
WAIT_QUEUE_ELEMENT_CHECK(wq, wq_element);
wq_next_element = (wait_queue_element_t)
queue_next((queue_t) wq_element);
if (wq_element->wqe_type == WAIT_QUEUE_LINK) {
wql = (wait_queue_link_t)wq_element;
wq_set = wql->wql_setqueue;
wqs_lock(wq_set);
wait_queue_unlink_locked(wq, wq_set, wql);
wqs_unlock(wq_set);
enqueue(links, &wql->wql_links);
}
wq_element = wq_next_element;
}
wait_queue_unlock(wq);
splx(s);
while(!queue_empty(links)) {
wql = (wait_queue_link_t) dequeue(links);
kfree((vm_offset_t) wql, sizeof(struct wait_queue_link));
}
return(KERN_SUCCESS);
}
/*
* Routine: wait_queue_unlink
* Purpose:
* Remove the linkage between a wait queue and a set,
* freeing the linkage structure.
* Conditions:
* The wait queue being must be a member set queue
*/
kern_return_t
wait_queue_unlink(
wait_queue_t wq,
wait_queue_set_t wq_set)
{
wait_queue_element_t wq_element;
wait_queue_link_t wql;
queue_t q;
spl_t s;
if (!wait_queue_is_valid(wq) || !wait_queue_is_set(wq_set)) {
return KERN_INVALID_ARGUMENT;
}
s = splsched();
wait_queue_lock(wq);
q = &wq->wq_queue;
wq_element = (wait_queue_element_t) queue_first(q);
while (!queue_end(q, (queue_entry_t)wq_element)) {
WAIT_QUEUE_ELEMENT_CHECK(wq, wq_element);
if (wq_element->wqe_type == WAIT_QUEUE_LINK ||
wq_element->wqe_type == WAIT_QUEUE_LINK_NOALLOC) {
wql = (wait_queue_link_t)wq_element;
if (wql->wql_setqueue == wq_set) {
boolean_t alloced;
alloced = (wql->wql_type == WAIT_QUEUE_LINK);
wqs_lock(wq_set);
wait_queue_unlink_locked(wq, wq_set, wql);
wqs_unlock(wq_set);
wait_queue_unlock(wq);
splx(s);
if (alloced)
zfree(_wait_queue_link_zone, wql);
return KERN_SUCCESS;
}
}
wq_element = (wait_queue_element_t)
queue_next((queue_t) wq_element);
}
wait_queue_unlock(wq);
splx(s);
return KERN_NOT_IN_SET;
}
/*
* Routine: wait_queue_unlink
* Purpose:
* Remove the linkage between a wait queue and a set,
* freeing the linkage structure.
* Conditions:
* The wait queue being must be a member set queue
*/
kern_return_t
wait_queue_unlink(
wait_queue_t wq,
wait_queue_set_t wq_set)
{
wait_queue_element_t wq_element;
wait_queue_link_t wql;
queue_t q;
spl_t s;
if (!wait_queue_is_queue(wq) || !wait_queue_is_set(wq_set)) {
return KERN_INVALID_ARGUMENT;
}
s = splsched();
wait_queue_lock(wq);
q = &wq->wq_queue;
wq_element = (wait_queue_element_t) queue_first(q);
while (!queue_end(q, (queue_entry_t)wq_element)) {
WAIT_QUEUE_ELEMENT_CHECK(wq, wq_element);
if (wq_element->wqe_type == WAIT_QUEUE_LINK) {
wql = (wait_queue_link_t)wq_element;
if (wql->wql_setqueue == wq_set) {
wqs_lock(wq_set);
wait_queue_unlink_locked(wq, wq_set, wql);
wqs_unlock(wq_set);
wait_queue_unlock(wq);
splx(s);
kfree((vm_offset_t)wql, sizeof(struct wait_queue_link));
return KERN_SUCCESS;
}
}
wq_element = (wait_queue_element_t)
queue_next((queue_t) wq_element);
}
wait_queue_unlock(wq);
splx(s);
return KERN_NOT_IN_SET;
}
/*
* Routine: _wait_queue_select64_one
* Purpose:
* Select the best thread off a wait queue that meet the
* supplied criteria.
* Conditions:
* at splsched
* wait queue locked
* possibly recursive
* Returns:
* a locked thread - if one found
* Note:
* This is where the sync policy of the wait queue comes
* into effect. For now, we just assume FIFO/LIFO.
*/
static thread_t
_wait_queue_select64_one(
wait_queue_t wq,
event64_t event)
{
wait_queue_element_t wq_element;
wait_queue_element_t wqe_next;
thread_t t = THREAD_NULL;
queue_t q;
q = &wq->wq_queue;
wq_element = (wait_queue_element_t) queue_first(q);
while (!queue_end(q, (queue_entry_t)wq_element)) {
WAIT_QUEUE_ELEMENT_CHECK(wq, wq_element);
wqe_next = (wait_queue_element_t)
queue_next((queue_t) wq_element);
/*
* We may have to recurse if this is a compound wait queue.
*/
if (wq_element->wqe_type == WAIT_QUEUE_LINK ||
wq_element->wqe_type == WAIT_QUEUE_LINK_NOALLOC) {
wait_queue_link_t wql = (wait_queue_link_t)wq_element;
wait_queue_set_t set_queue = wql->wql_setqueue;
/*
* We have to check the set wait queue. If the set
* supports pre-posting, it isn't already preposted,
* and we didn't find a thread in the set, then mark it.
*
* If we later find a thread, there may be a spurious
* pre-post here on this set. The wait side has to check
* for that either pre- or post-wait.
*/
wqs_lock(set_queue);
if (! wait_queue_empty(&set_queue->wqs_wait_queue)) {
t = _wait_queue_select64_one(&set_queue->wqs_wait_queue, event);
}
if (t != THREAD_NULL) {
wqs_unlock(set_queue);
return t;
}
if (event == NO_EVENT64 && set_queue->wqs_prepost && !wql_is_preposted(wql)) {
queue_t ppq = &set_queue->wqs_preposts;
queue_enter(ppq, wql, wait_queue_link_t, wql_preposts);
}
wqs_unlock(set_queue);
} else {
/*
* Otherwise, its a thread. If it is waiting on
* the event we are posting to this queue, pull
* it off the queue and stick it in out wake_queue.
*/
t = (thread_t)wq_element;
if (t->wait_event == event) {
thread_lock(t);
remqueue((queue_entry_t) t);
t->wait_queue = WAIT_QUEUE_NULL;
t->wait_event = NO_EVENT64;
t->at_safe_point = FALSE;
return t; /* still locked */
}
t = THREAD_NULL;
}
wq_element = wqe_next;
}
return THREAD_NULL;
}
/*
* Routine: _wait_queue_select64_all
* Purpose:
* Select all threads off a wait queue that meet the
* supplied criteria.
* Conditions:
* at splsched
* wait queue locked
* wake_queue initialized and ready for insertion
* possibly recursive
* Returns:
* a queue of locked threads
*/
static void
_wait_queue_select64_all(
wait_queue_t wq,
event64_t event,
queue_t wake_queue)
{
wait_queue_element_t wq_element;
wait_queue_element_t wqe_next;
queue_t q;
q = &wq->wq_queue;
wq_element = (wait_queue_element_t) queue_first(q);
while (!queue_end(q, (queue_entry_t)wq_element)) {
WAIT_QUEUE_ELEMENT_CHECK(wq, wq_element);
wqe_next = (wait_queue_element_t)
queue_next((queue_t) wq_element);
/*
* We may have to recurse if this is a compound wait queue.
*/
if (wq_element->wqe_type == WAIT_QUEUE_LINK ||
wq_element->wqe_type == WAIT_QUEUE_LINK_NOALLOC) {
wait_queue_link_t wql = (wait_queue_link_t)wq_element;
wait_queue_set_t set_queue = wql->wql_setqueue;
/*
* We have to check the set wait queue. If it is marked
* as pre-post, and it is the "generic event" then mark
* it pre-posted now (if not already).
*/
wqs_lock(set_queue);
if (event == NO_EVENT64 && set_queue->wqs_prepost && !wql_is_preposted(wql)) {
queue_t ppq = &set_queue->wqs_preposts;
queue_enter(ppq, wql, wait_queue_link_t, wql_preposts);
}
if (! wait_queue_empty(&set_queue->wqs_wait_queue))
_wait_queue_select64_all(&set_queue->wqs_wait_queue, event, wake_queue);
wqs_unlock(set_queue);
} else {
/*
* Otherwise, its a thread. If it is waiting on
* the event we are posting to this queue, pull
* it off the queue and stick it in out wake_queue.
*/
thread_t t = (thread_t)wq_element;
if (t->wait_event == event) {
thread_lock(t);
remqueue((queue_entry_t) t);
enqueue (wake_queue, (queue_entry_t) t);
t->wait_queue = WAIT_QUEUE_NULL;
t->wait_event = NO_EVENT64;
t->at_safe_point = FALSE;
/* returned locked */
}
}
wq_element = wqe_next;
}
}
/*
* Routine: _wait_queue_select64_all
* Purpose:
* Select all threads off a wait queue that meet the
* supplied criteria.
* Conditions:
* at splsched
* wait queue locked
* wake_queue initialized and ready for insertion
* possibly recursive
* Returns:
* a queue of locked threads
*/
static void
_wait_queue_select64_all(
wait_queue_t wq,
event64_t event,
queue_t wake_queue)
{
wait_queue_element_t wq_element;
wait_queue_element_t wqe_next;
queue_t q;
q = &wq->wq_queue;
wq_element = (wait_queue_element_t) queue_first(q);
while (!queue_end(q, (queue_entry_t)wq_element)) {
WAIT_QUEUE_ELEMENT_CHECK(wq, wq_element);
wqe_next = (wait_queue_element_t)
queue_next((queue_t) wq_element);
/*
* We may have to recurse if this is a compound wait queue.
*/
if (wq_element->wqe_type == WAIT_QUEUE_LINK) {
wait_queue_link_t wql = (wait_queue_link_t)wq_element;
wait_queue_t set_queue;
/*
* We have to check the set wait queue.
*/
set_queue = (wait_queue_t)wql->wql_setqueue;
wait_queue_lock(set_queue);
if (set_queue->wq_isprepost) {
wait_queue_set_t wqs = (wait_queue_set_t)set_queue;
/*
* Preposting is only for sets and wait queue
* is the first element of set
*/
wqs->wqs_refcount++;
}
if (! wait_queue_empty(set_queue))
_wait_queue_select64_all(set_queue, event, wake_queue);
wait_queue_unlock(set_queue);
} else {
/*
* Otherwise, its a thread. If it is waiting on
* the event we are posting to this queue, pull
* it off the queue and stick it in out wake_queue.
*/
thread_t t = (thread_t)wq_element;
if (t->wait_event == event) {
thread_lock(t);
remqueue(q, (queue_entry_t) t);
enqueue (wake_queue, (queue_entry_t) t);
t->wait_queue = WAIT_QUEUE_NULL;
t->wait_event = NO_EVENT64;
t->at_safe_point = FALSE;
/* returned locked */
}
}
wq_element = wqe_next;
}
}
/*
* Routine: wait_queue_peek64_locked
* Purpose:
* Select the best thread from a wait queue that meet the
* supplied criteria, but leave it on the queue it was
* found on. The thread, and the actual wait_queue the
* thread was found on are identified.
* Conditions:
* at splsched
* wait queue locked
* possibly recursive
* Returns:
* a locked thread - if one found
* a locked waitq - the one the thread was found on
* Note:
* Both the waitq the thread was actually found on, and
* the supplied wait queue, are locked after this.
*/
__private_extern__ void
wait_queue_peek64_locked(
wait_queue_t wq,
event64_t event,
thread_t *tp,
wait_queue_t *wqp)
{
wait_queue_element_t wq_element;
wait_queue_element_t wqe_next;
thread_t t;
queue_t q;
assert(wq->wq_fifo);
*tp = THREAD_NULL;
q = &wq->wq_queue;
wq_element = (wait_queue_element_t) queue_first(q);
while (!queue_end(q, (queue_entry_t)wq_element)) {
WAIT_QUEUE_ELEMENT_CHECK(wq, wq_element);
wqe_next = (wait_queue_element_t)
queue_next((queue_t) wq_element);
/*
* We may have to recurse if this is a compound wait queue.
*/
if (wq_element->wqe_type == WAIT_QUEUE_LINK) {
wait_queue_link_t wql = (wait_queue_link_t)wq_element;
wait_queue_t set_queue;
/*
* We have to check the set wait queue.
*/
set_queue = (wait_queue_t)wql->wql_setqueue;
wait_queue_lock(set_queue);
if (! wait_queue_empty(set_queue)) {
wait_queue_peek64_locked(set_queue, event, tp, wqp);
}
if (*tp != THREAD_NULL) {
if (*wqp != set_queue)
wait_queue_unlock(set_queue);
return; /* thread and its waitq locked */
}
wait_queue_unlock(set_queue);
} else {
/*
* Otherwise, its a thread. If it is waiting on
* the event we are posting to this queue, return
* it locked, but leave it on the queue.
*/
thread_t t = (thread_t)wq_element;
if (t->wait_event == event) {
thread_lock(t);
*tp = t;
*wqp = wq;
return;
}
}
wq_element = wqe_next;
}
}
