kernel: Make statements evaluate boolean expressions

MISRA-C requires that the if statement has essentially Boolean type.

MISRA-C rule 14.4

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>

include/kernel.h

@@ -2589,7 +2589,7 @@ static inline int k_work_submit_to_user_queue(struct k_work_q *work_q,
 		/* Couldn't insert into the queue. Clear the pending bit
 		 * so the work item can be submitted again
 		 */
-		if (ret) {
+		if (ret != 0) {
 			atomic_clear_bit(work->flags, K_WORK_STATE_PENDING);
 		}
 	}
@@ -4211,7 +4211,7 @@ extern void *k_calloc(size_t nmemb, size_t size);
 /* private - implementation data created as needed, per-type */
 struct _poller {
 	struct k_thread *thread;
-	volatile int is_polling;
+	volatile bool is_polling;
 };
 
 /* private - types bit positions */

kernel/include/syscall_handler.h

@@ -399,7 +399,7 @@ static inline int _obj_validation_check(struct _k_object *ko,
 	ret = _k_object_validate(ko, otype, init);
 
 #ifdef CONFIG_PRINTK
-	if (ret) {
+	if (ret != 0) {
 		_dump_object_error(ret, obj, ko, otype);
 	}
 #else

kernel/int_latency_bench.c

@@ -176,7 +176,7 @@ void int_latency_show(void)
 {
 	u32_t intHandlerLatency = 0U;
 
-	if (!int_latency_bench_ready) {
+	if (int_latency_bench_ready == 0) {
 		printk("error: int_latency_init() has not been invoked\n");
 		return;
 	}

kernel/mailbox.c

@@ -204,7 +204,7 @@ static void mbox_message_dispose(struct k_mbox_msg *rx_msg)
 	 * asynchronous send: free asynchronous message descriptor +
 	 * dummy thread pair, then give semaphore (if needed)
 	 */
-	if (sending_thread->base.thread_state & _THREAD_DUMMY) {
+	if ((sending_thread->base.thread_state & _THREAD_DUMMY) != 0) {
 		struct k_sem *async_sem = tx_msg->_async_sem;
 
 		mbox_async_free((struct k_mbox_async *)sending_thread);
@@ -274,7 +274,8 @@ static int mbox_message_put(struct k_mbox *mbox, struct k_mbox_msg *tx_msg,
 			 * note: dummy sending thread sits (unqueued)
 			 * until the receiver consumes the message
 			 */
-			if (sending_thread->base.thread_state & _THREAD_DUMMY) {
+			if ((sending_thread->base.thread_state & _THREAD_DUMMY)
+			    != 0) {
 				_reschedule(key);
 				return 0;
 			}
@@ -297,7 +298,7 @@ static int mbox_message_put(struct k_mbox *mbox, struct k_mbox_msg *tx_msg,
 
 #if (CONFIG_NUM_MBOX_ASYNC_MSGS > 0)
 	/* asynchronous send: dummy thread waits on tx queue for receiver */
-	if (sending_thread->base.thread_state & _THREAD_DUMMY) {
+	if ((sending_thread->base.thread_state & _THREAD_DUMMY) != 0) {
 		_pend_thread(sending_thread, &mbox->tx_msg_queue, K_FOREVER);
 		irq_unlock(key);
 		return 0;

kernel/mem_domain.c

@@ -84,7 +84,7 @@ void k_mem_domain_init(struct k_mem_domain *domain, u8_t num_parts,
 	domain->num_partitions = 0;
 	(void)memset(domain->partitions, 0, sizeof(domain->partitions));
 
-	if (num_parts) {
+	if (num_parts != 0) {
 		u32_t i;
 
 		for (i = 0U; i < num_parts; i++) {

kernel/msg_q.c

@@ -101,7 +101,7 @@ void k_msgq_cleanup(struct k_msgq *q)
 {
 	__ASSERT_NO_MSG(!_waitq_head(&q->wait_q));
 
-	if (q->flags & K_MSGQ_FLAG_ALLOC) {
+	if ((q->flags & K_MSGQ_FLAG_ALLOC) != 0) {
 		k_free(q->buffer_start);
 		q->flags &= ~K_MSGQ_FLAG_ALLOC;
 	}

kernel/pipes.c

@@ -150,9 +150,9 @@ int _impl_k_pipe_alloc_init(struct k_pipe *pipe, size_t size)
 	void *buffer;
 	int ret;
 
-	if (size) {
+	if (size != 0) {
 		buffer = z_thread_malloc(size);
-		if (buffer) {
+		if (buffer != NULL) {
 			k_pipe_init(pipe, buffer, size);
 			pipe->flags = K_PIPE_FLAG_ALLOC;
 			ret = 0;
@@ -181,7 +181,7 @@ void k_pipe_cleanup(struct k_pipe *pipe)
 	__ASSERT_NO_MSG(!_waitq_head(&pipe->wait_q.readers));
 	__ASSERT_NO_MSG(!_waitq_head(&pipe->wait_q.writers));
 
-	if (pipe->flags & K_PIPE_FLAG_ALLOC) {
+	if ((pipe->flags & K_PIPE_FLAG_ALLOC) != 0) {
 		k_free(pipe->buffer);
 		pipe->buffer = NULL;
 		pipe->flags &= ~K_PIPE_FLAG_ALLOC;
@@ -415,7 +415,7 @@ static void pipe_thread_ready(struct k_thread *thread)
 	unsigned int  key;
 
 #if (CONFIG_NUM_PIPE_ASYNC_MSGS > 0)
-	if (thread->base.thread_state & _THREAD_DUMMY) {
+	if ((thread->base.thread_state & _THREAD_DUMMY) != 0) {
 		pipe_async_finish((struct k_pipe_async *)thread);
 		return;
 	}

kernel/poll.c

@@ -59,7 +59,7 @@ static inline int is_condition_met(struct k_poll_event *event, u32_t *state)
 		}
 		break;
 	case K_POLL_TYPE_SIGNAL:
-		if (event->signal->signaled) {
+		if (event->signal->signaled != 0) {
 			*state = K_POLL_STATE_SIGNALED;
 			return 1;
 		}
@@ -183,7 +183,7 @@ int _impl_k_poll(struct k_poll_event *events, int num_events, s32_t timeout)
 	int last_registered = -1, rc;
 	unsigned int key;
 
-	struct _poller poller = { .thread = _current, .is_polling = 1, };
+	struct _poller poller = { .thread = _current, .is_polling = true, };
 
 	/* find events whose condition is already fulfilled */
 	for (int ii = 0; ii < num_events; ii++) {
@@ -192,7 +192,7 @@ int _impl_k_poll(struct k_poll_event *events, int num_events, s32_t timeout)
 		key = irq_lock();
 		if (is_condition_met(&events[ii], &state)) {
 			set_event_ready(&events[ii], state);
-			poller.is_polling = 0;
+			poller.is_polling = false;
 		} else if (timeout != K_NO_WAIT && poller.is_polling) {
 			rc = register_event(&events[ii], &poller);
 			if (rc == 0) {
@@ -217,7 +217,7 @@ int _impl_k_poll(struct k_poll_event *events, int num_events, s32_t timeout)
 		return 0;
 	}
 
-	poller.is_polling = 0;
+	poller.is_polling = false;
 
 	if (timeout == K_NO_WAIT) {
 		irq_unlock(key);
@@ -331,7 +331,7 @@ static int signal_poll_event(struct k_poll_event *event, u32_t state)
 	__ASSERT(event->poller->thread != NULL,
 		 "poller should have a thread\n");
 
-	event->poller->is_polling = 0;
+	event->poller->is_polling = true;
 
 	if (!_is_thread_pending(thread)) {
 		goto ready_event;

kernel/queue.c

@@ -237,7 +237,7 @@ void k_queue_append_list(struct k_queue *queue, void *head, void *tail)
 #if !defined(CONFIG_POLL)
 	struct k_thread *thread = NULL;
 
-	if (head) {
+	if (head != NULL) {
 		thread = _unpend_first_thread(&queue->wait_q);
 	}
 

kernel/thread.c

@@ -244,7 +244,7 @@ void _check_stack_sentinel(void)
 {
 	u32_t *stack;
 
-	if (_current->base.thread_state & _THREAD_DUMMY) {
+	if ((_current->base.thread_state & _THREAD_DUMMY) != 0) {
 		return;
 	}
 
@@ -403,7 +403,7 @@ void _setup_new_thread(struct k_thread *new_thread,
 					new_thread);
 	}
 
-	if (options & K_INHERIT_PERMS) {
+	if ((options & K_INHERIT_PERMS) != 0) {
 		_thread_perms_inherit(_current, new_thread);
 	}
 #endif

kernel/timer.c

@@ -9,6 +9,7 @@
 #include <init.h>
 #include <wait_q.h>
 #include <syscall_handler.h>
+#include <stdbool.h>
 
 extern struct k_timer _k_timer_list_start[];
 extern struct k_timer _k_timer_list_end[];
@@ -64,7 +65,7 @@ void _timer_expiration_handler(struct _timeout *t)
 	timer->status += 1;
 
 	/* invoke timer expiry function */
-	if (timer->expiry_fn) {
+	if (timer->expiry_fn != NULL) {
 		timer->expiry_fn(timer);
 	}
 
@@ -149,7 +150,7 @@ Z_SYSCALL_HANDLER(k_timer_start, timer, duration_p, period_p)
 void _impl_k_timer_stop(struct k_timer *timer)
 {
 	unsigned int key = irq_lock();
-	int inactive = (_abort_timeout(&timer->timeout) == _INACTIVE);
+	bool inactive = (_abort_timeout(&timer->timeout) == _INACTIVE);
 
 	irq_unlock(key);
 
@@ -157,7 +158,7 @@ void _impl_k_timer_stop(struct k_timer *timer)
 		return;
 	}
 
-	if (timer->stop_fn) {
+	if (timer->stop_fn != NULL) {
 		timer->stop_fn(timer);
 	}
 

kernel/userspace.c

@@ -174,7 +174,7 @@ static bool _thread_idx_alloc(u32_t *tidx)
 	for (i = 0; i < CONFIG_MAX_THREAD_BYTES; i++) {
 		idx = find_lsb_set(_thread_idx_map[i]);
 
-		if (idx) {
+		if (idx != 0) {
 			*tidx = base + (idx - 1);
 
 			sys_bitfield_clear_bit((mem_addr_t)_thread_idx_map,
@@ -334,7 +334,7 @@ static int thread_index_get(struct k_thread *t)
 static void unref_check(struct _k_object *ko)
 {
 	for (int i = 0; i < CONFIG_MAX_THREAD_BYTES; i++) {
-		if (ko->perms[i]) {
+		if (ko->perms[i] != 0) {
 			return;
 		}
 	}
@@ -360,7 +360,7 @@ static void unref_check(struct _k_object *ko)
 	}
 
 #ifdef CONFIG_DYNAMIC_OBJECTS
-	if (ko->flags & K_OBJ_FLAG_ALLOC) {
+	if ((ko->flags & K_OBJ_FLAG_ALLOC) != 0) {
 		struct dyn_obj *dyn_obj =
 			CONTAINER_OF(ko, struct dyn_obj, kobj);
 		rb_remove(&obj_rb_tree, &dyn_obj->node);
@@ -438,7 +438,7 @@ static int thread_perms_test(struct _k_object *ko)
 {
 	int index;
 
-	if (ko->flags & K_OBJ_FLAG_PUBLIC) {
+	if ((ko->flags & K_OBJ_FLAG_PUBLIC) != 0) {
 		return 1;
 	}
 
@@ -663,7 +663,7 @@ char *z_user_string_alloc_copy(char *src, size_t maxlen)
 
 	key = irq_lock();
 	actual_len = z_user_string_nlen(src, maxlen, &err);
-	if (err) {
+	if (err != 0) {
 		goto out;
 	}
 	if (actual_len == maxlen) {
@@ -690,7 +690,7 @@ int z_user_string_copy(char *dst, char *src, size_t maxlen)
 
 	key = irq_lock();
 	actual_len = z_user_string_nlen(src, maxlen, &err);
-	if (err) {
+	if (err != 0) {
 		ret = EFAULT;
 		goto out;
 	}

kernel/userspace_handler.c

@@ -19,7 +19,7 @@ static struct _k_object *validate_any_object(void *obj)
 	 * initialized
 	 */
 	ret = _k_object_validate(ko, K_OBJ_ANY, _OBJ_INIT_ANY);
-	if (ret) {
+	if (ret != 0) {
 #ifdef CONFIG_PRINTK
 		_dump_object_error(ret, obj, ko, K_OBJ_ANY);
 #endif

lib/rbtree/rb.c

@@ -21,7 +21,7 @@ enum rb_color { RED = 0, BLACK = 1 };
 static struct rbnode *get_child(struct rbnode *n, int side)
 {
 	CHECK(n);
-	if (side) {
+	if (side != 0) {
 		return n->children[1];
 	}
 
@@ -34,7 +34,7 @@ static struct rbnode *get_child(struct rbnode *n, int side)
 static void set_child(struct rbnode *n, int side, void *val)
 {
 	CHECK(n);
-	if (side) {
+	if (side != 0) {
 		n->children[1] = val;
 	} else {
 		uintptr_t old = (uintptr_t) n->children[0];
@@ -87,7 +87,7 @@ static int find_and_stack(struct rbtree *tree, struct rbnode *node,
 		int side = tree->lessthan_fn(node, stack[sz - 1]) ? 0 : 1;
 		struct rbnode *ch = get_child(stack[sz - 1], side);
 
-		if (ch) {
+		if (ch != NULL) {
 			stack[sz++] = ch;
 		} else {
 			break;
@@ -400,7 +400,7 @@ void rb_remove(struct rbtree *tree, struct rbnode *node)
 		 * pointers, so the stack tracking this structure
 		 * needs to be swapped too!
 		 */
-		if (hiparent) {
+		if (hiparent != NULL) {
 			set_child(hiparent, get_side(hiparent, node), node2);
 		} else {
 			tree->root = node2;
@@ -440,7 +440,7 @@ void rb_remove(struct rbtree *tree, struct rbnode *node)
 	/* Removing the root */
 	if (stacksz < 2) {
 		tree->root = child;
-		if (child) {
+		if (child != NULL) {
 			set_color(child, BLACK);
 		} else {
 			tree->max_depth = 0;
@@ -523,7 +523,7 @@ static inline struct rbnode *stack_left_limb(struct rbnode *n,
 	f->stack[f->top] = n;
 	f->is_left[f->top] = 0;
 
-	while ((n = get_child(n, 0))) {
+	while ((n = get_child(n, 0)) != NULL) {
 		f->top++;
 		f->stack[f->top] = n;
 		f->is_left[f->top] = 1;
@@ -568,7 +568,7 @@ struct rbnode *_rb_foreach_next(struct rbtree *tree, struct _rb_foreach *f)
 	 * above with is_left set to 0, so this condition still works
 	 * even if node has no parent).
 	 */
-	if (f->is_left[f->top]) {
+	if (f->is_left[f->top] != 0) {
 		return f->stack[--f->top];
 	}
 
@@ -576,7 +576,7 @@ struct rbnode *_rb_foreach_next(struct rbtree *tree, struct _rb_foreach *f)
 	 * parent was already walked, so walk up the stack looking for
 	 * a left child (whose parent is unwalked, and thus next).
 	 */
-	while (f->top > 0 && !f->is_left[f->top]) {
+	while ((f->top > 0) && (f->is_left[f->top] == 0)) {
 		f->top--;
 	}