FreeRTOS源码解析 -> vTaskResume（）

#if ( INCLUDE_vTaskSuspend == 1 )

void vTaskResume( xTaskHandle pxTaskToResume )
{
tskTCB *pxTCB;

/* It does not make sense to resume the calling task. */
configASSERT( pxTaskToResume );

/* Remove the task from whichever list it is currently in, and place
it in the ready list. */
pxTCB = ( tskTCB * ) pxTaskToResume;

/* The parameter cannot be NULL as it is impossible to resume the
currently executing task. */
//要恢复的task不为空并且不是当前正在运行的task（如果是当前运行的还恢复个毛线）
//熟悉的链表操作啊
if( ( pxTCB != NULL ) && ( pxTCB != pxCurrentTCB ) )
{
//进入临界区
taskENTER_CRITICAL();
{
//判断要恢复的task是否在挂起列表中
if( xTaskIsTaskSuspended( pxTCB ) == pdTRUE )
{
traceTASK_RESUME( pxTCB );

/* As we are in a critical section we can access the ready
lists even if the scheduler is suspended. */
//从挂起链表中删除，加入到ready队列中（恢复到就绪态）
vListRemove(  &( pxTCB->xGenericListItem ) );
prvAddTaskToReadyQueue( pxTCB );

//如果恢复的task优先级比当前正在运行的任务的优先级高，强制一次任务调度
//这里为什么不去判断当前调度器是否在运行（之前可是都判断了的）？？？？
/* We may have just resumed a higher priority task. */
if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
{
/* This yield may not cause the task just resumed to run, but
will leave the lists in the correct state for the next yield. */
/*强制进行一次上下文切换*/
portYIELD_WITHIN_API();
}
}
}
//退出临界区
taskEXIT_CRITICAL();
}
}

#endif