iiod: thread_pool: Add helper thread_pool_purge_events()

Factorize the code that purges all the data left in the event file
descriptor into a function named thread_pool_purge_events().

This function is only called once for now, but it will be used again in
a future commit.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>

iiod/thread-pool.c

@@ -157,11 +157,18 @@ void thread_pool_stop(struct thread_pool *pool)
 	} while (ret == -1 && errno == EINTR);
 }
 
-void thread_pool_stop_and_wait(struct thread_pool *pool)
+static void thread_pool_purge_events(struct thread_pool *pool)
 {
 	uint64_t e;
 	int ret;
 
+	do {
+		ret = read(pool->stop_fd, &e, sizeof(e));
+	} while (ret != -1 || errno == EINTR);
+}
+
+void thread_pool_stop_and_wait(struct thread_pool *pool)
+{
 	thread_pool_stop(pool);
 
 	pthread_mutex_lock(&pool->thread_count_lock);
@@ -170,9 +177,7 @@ void thread_pool_stop_and_wait(struct thread_pool *pool)
 				&pool->thread_count_lock);
 	pthread_mutex_unlock(&pool->thread_count_lock);
 
-	do {
-		ret = read(pool->stop_fd, &e, sizeof(e));
-	} while (ret != -1 || errno == EINTR);
+	thread_pool_purge_events(pool);
 }
 
 bool thread_pool_is_stopped(const struct thread_pool *pool)