kernel/queue: Spinlockify

Straightforward port.  Each struct k_queue object gets a spinlock to
control obvious data ownership.

Note that this port actually discovered a preexisting bug: the -ENOMEM
case in queue_insert() was failing to release the lock.  But because
the tests that hit that path didn't rely on other threads being
scheduled, they ran to successful completion even with interrupts
disabled.  The spinlock API detects that as a recursive lock when
asserts are enabled.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>

include/kernel.h

@@ -1728,6 +1728,7 @@ static inline u32_t k_uptime_delta_32(s64_t *reftime)
 
 struct k_queue {
 	sys_sflist_t data_q;
+	struct k_spinlock lock;
 	union {
 		_wait_q_t wait_q;
 

kernel/queue.c

@@ -85,6 +85,7 @@ SYS_INIT(init_queue_module, PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_OBJECTS);
 void _impl_k_queue_init(struct k_queue *queue)
 {
 	sys_sflist_init(&queue->data_q);
+	queue->lock = (struct k_spinlock) {};
 	_waitq_init(&queue->wait_q);
 #if defined(CONFIG_POLL)
 	sys_dlist_init(&queue->poll_events);
@@ -122,7 +123,7 @@ static inline void handle_poll_events(struct k_queue *queue, u32_t state)
 
 void _impl_k_queue_cancel_wait(struct k_queue *queue)
 {
-	u32_t key = irq_lock();
+	k_spinlock_key_t key = k_spin_lock(&queue->lock);
 #if !defined(CONFIG_POLL)
 	struct k_thread *first_pending_thread;
 
@@ -135,7 +136,7 @@ void _impl_k_queue_cancel_wait(struct k_queue *queue)
 	handle_poll_events(queue, K_POLL_STATE_CANCELLED);
 #endif /* !CONFIG_POLL */
 
-	_reschedule_irqlock(key);
+	_reschedule(&queue->lock, key);
 }
 
 #ifdef CONFIG_USERSPACE
@@ -146,7 +147,7 @@ Z_SYSCALL_HANDLER1_SIMPLE_VOID(k_queue_cancel_wait, K_OBJ_QUEUE,
 static s32_t queue_insert(struct k_queue *queue, void *prev, void *data,
 			  bool alloc)
 {
-	u32_t key = irq_lock();
+	k_spinlock_key_t key = k_spin_lock(&queue->lock);
 #if !defined(CONFIG_POLL)
 	struct k_thread *first_pending_thread;
 
@@ -154,7 +155,7 @@ static s32_t queue_insert(struct k_queue *queue, void *prev, void *data,
 
 	if (first_pending_thread != NULL) {
 		prepare_thread_to_run(first_pending_thread, data);
-		_reschedule_irqlock(key);
+		_reschedule(&queue->lock, key);
 		return 0;
 	}
 #endif /* !CONFIG_POLL */
@@ -165,6 +166,7 @@ static s32_t queue_insert(struct k_queue *queue, void *prev, void *data,
 
 		anode = z_thread_malloc(sizeof(*anode));
 		if (anode == NULL) {
+			k_spin_unlock(&queue->lock, key);
 			return -ENOMEM;
 		}
 		anode->data = data;
@@ -179,7 +181,7 @@ static s32_t queue_insert(struct k_queue *queue, void *prev, void *data,
 	handle_poll_events(queue, K_POLL_STATE_DATA_AVAILABLE);
 #endif /* CONFIG_POLL */
 
-	_reschedule_irqlock(key);
+	_reschedule(&queue->lock, key);
 	return 0;
 }
 
@@ -234,7 +236,7 @@ void k_queue_append_list(struct k_queue *queue, void *head, void *tail)
 {
 	__ASSERT(head && tail, "invalid head or tail");
 
-	unsigned int key = irq_lock();
+	k_spinlock_key_t key = k_spin_lock(&queue->lock);
 #if !defined(CONFIG_POLL)
 	struct k_thread *thread = NULL;
 
@@ -257,7 +259,7 @@ void k_queue_append_list(struct k_queue *queue, void *head, void *tail)
 	handle_poll_events(queue, K_POLL_STATE_DATA_AVAILABLE);
 #endif /* !CONFIG_POLL */
 
-	_reschedule_irqlock(key);
+	_reschedule(&queue->lock, key);
 }
 
 void k_queue_merge_slist(struct k_queue *queue, sys_slist_t *list)
@@ -282,7 +284,7 @@ static void *k_queue_poll(struct k_queue *queue, s32_t timeout)
 {
 	struct k_poll_event event;
 	int err, elapsed = 0, done = 0;
-	unsigned int key;
+	k_spinlock_key_t key;
 	void *val;
 	u32_t start;
 
@@ -302,12 +304,9 @@ static void *k_queue_poll(struct k_queue *queue, s32_t timeout)
 			return NULL;
 		}
 
-		/* sys_sflist_* aren't threadsafe, so must be always protected
+		key = k_spin_lock(&queue->lock);
-		 * by irq_lock.
-		 */
-		key = irq_lock();
 		val = z_queue_node_peek(sys_sflist_get(&queue->data_q), true);
-		irq_unlock(key);
+		k_spin_unlock(&queue->lock, key);
 
 		if ((val == NULL) && (timeout != K_FOREVER)) {
 			elapsed = k_uptime_get_32() - start;
@@ -321,32 +320,30 @@ static void *k_queue_poll(struct k_queue *queue, s32_t timeout)
 
 void *_impl_k_queue_get(struct k_queue *queue, s32_t timeout)
 {
-	unsigned int key;
+	k_spinlock_key_t key = k_spin_lock(&queue->lock);
 	void *data;
 
-	key = irq_lock();
-
 	if (likely(!sys_sflist_is_empty(&queue->data_q))) {
 		sys_sfnode_t *node;
 
 		node = sys_sflist_get_not_empty(&queue->data_q);
 		data = z_queue_node_peek(node, true);
-		irq_unlock(key);
+		k_spin_unlock(&queue->lock, key);
 		return data;
 	}
 
 	if (timeout == K_NO_WAIT) {
-		irq_unlock(key);
+		k_spin_unlock(&queue->lock, key);
 		return NULL;
 	}
 
 #if defined(CONFIG_POLL)
-	irq_unlock(key);
+	k_spin_unlock(&queue->lock, key);
 
 	return k_queue_poll(queue, timeout);
 
 #else
-	int ret = _pend_curr_irqlock(key, &queue->wait_q, timeout);
+	int ret = _pend_curr(&queue->lock, key, &queue->wait_q, timeout);
 
 	return (ret != 0) ? NULL : _current->base.swap_data;
 #endif /* CONFIG_POLL */