pthread_cond_broadcast use wait_count for judement

This commit fixes the comment from https://github.com/apache/nuttx/pull/14581

Signed-off-by: hujun5 <hujun5@xiaomi.com>

include/pthread.h

@@ -269,7 +269,7 @@ struct pthread_cond_s
 {
   sem_t sem;
   clockid_t clockid;
-  volatile int16_t lock_count;
+  uint16_t wait_count;
 };
 
 #ifndef __PTHREAD_COND_T_DEFINED

libs/libc/pthread/pthread_condinit.c

@@ -74,7 +74,7 @@ int pthread_cond_init(FAR pthread_cond_t *cond,
   else
     {
       cond->clockid = attr ? attr->clockid : CLOCK_REALTIME;
-      cond->lock_count = 0;
+      cond->wait_count = 0;
     }
 
   sinfo("Returning %d\n", ret);

sched/pthread/pthread_condbroadcast.c

@@ -42,7 +42,10 @@
  *
  * Description:
  *    A thread broadcast on a condition variable.
- *
+ *    pthread_cond_broadcast shall unblock all threads currently blocked on a
+ *    specified condition variable cond. We need own the mutex that threads
+ *    calling pthread_cond_wait or pthread_cond_timedwait have associated
+ *    with the condition variable during their wait.
  * Input Parameters:
  *   None
  *
@@ -56,7 +59,6 @@
 int pthread_cond_broadcast(FAR pthread_cond_t *cond)
 {
   int ret = OK;
-  int sval;
 
   sinfo("cond=%p\n", cond);
 
@@ -73,31 +75,22 @@ int pthread_cond_broadcast(FAR pthread_cond_t *cond)
 
       sched_lock();
 
-      /* Get the current value of the semaphore */
+      /* Loop until all of the waiting threads have been restarted. */
 
-      if (nxsem_get_value(&cond->sem, &sval) != OK)
+      while (cond->wait_count > 0)
         {
-          ret = EINVAL;
-        }
-      else
-        {
-          /* Loop until all of the waiting threads have been restarted. */
+          /* If the value is less than zero (meaning that one or more
+           * thread is waiting), then post the condition semaphore.
+           * Only the highest priority waiting thread will get to execute
+           */
 
-          while (sval < 0)
-            {
-              /* If the value is less than zero (meaning that one or more
-               * thread is waiting), then post the condition semaphore.
-               * Only the highest priority waiting thread will get to execute
-               */
+          ret = -nxsem_post(&cond->sem);
 
-              ret = -nxsem_post(&cond->sem);
+          /* Increment the semaphore count (as was done by the
+           * above post).
+           */
 
-              /* Increment the semaphore count (as was done by the
-               * above post).
-               */
-
-              sval++;
-            }
+          cond->wait_count--;
         }
 
       /* Now we can let the restarted threads run */

sched/pthread/pthread_condclockwait.c

@@ -113,7 +113,7 @@ int pthread_cond_clockwait(FAR pthread_cond_t *cond,
 
       sinfo("Give up mutex...\n");
 
-      cond->lock_count--;
+      cond->wait_count++;
 
       /* Give up the mutex */
 

sched/pthread/pthread_condsignal.c

@@ -41,6 +41,10 @@
  *
  * Description:
  *    A thread can signal on a condition variable.
+ *    pthread_cond_signal shall unblock a thread currently blocked on a
+ *    specified condition variable cond. We need own the mutex that threads
+ *    calling pthread_cond_wait or pthread_cond_timedwait have associated
+ *    with the condition variable during their wait.
  *
  * Input Parameters:
  *   None
@@ -64,10 +68,10 @@ int pthread_cond_signal(FAR pthread_cond_t *cond)
     }
   else
     {
-      if (cond->lock_count < 0)
+      if (cond->wait_count > 0)
         {
           sinfo("Signalling...\n");
-          cond->lock_count++;
+          cond->wait_count--;
           ret = -nxsem_post(&cond->sem);
         }
     }

sched/pthread/pthread_condwait.c

@@ -88,7 +88,7 @@ int pthread_cond_wait(FAR pthread_cond_t *cond, FAR pthread_mutex_t *mutex)
 
       sinfo("Give up mutex / take cond\n");
 
-      cond->lock_count--;
+      cond->wait_count++;
       ret = pthread_mutex_breaklock(mutex, &nlocks);
 
       status = -nxsem_wait_uninterruptible(&cond->sem);