Function rt_mp_alloc

src/mempool.c:281–365

* @brief This function will allocate a block from memory pool. * * @param mp is the memory pool object. * * @param time is the maximum waiting time for allocating memory. * - 0 for not waiting, allocating memory immediately. * * @return the allocated memory block or RT_NULL on allocated failed. */

 * @return the allocated memory block or RT_NULL on allocated failed.
 */
void *rt_mp_alloc(rt_mp_t mp, rt_int32_t time)
{
    rt_uint8_t *block_ptr;
    rt_base_t level;
    struct rt_thread *thread;
    rt_uint32_t before_sleep = 0;

    /* parameter check */
    RT_ASSERT(mp != RT_NULL);

    /* get current thread */
    thread = rt_thread_self();

    level = rt_spin_lock_irqsave(&(mp->spinlock));

    while (mp->block_free_count == 0)
    {
        /* memory block is unavailable. */
        if (time == 0)
        {
            rt_spin_unlock_irqrestore(&(mp->spinlock), level);

            rt_set_errno(-RT_ETIMEOUT);

            return RT_NULL;
        }

        RT_DEBUG_NOT_IN_INTERRUPT;

        thread->error = RT_EOK;

        /* need suspend thread */
        rt_thread_suspend_to_list(thread, &mp->suspend_thread, RT_IPC_FLAG_FIFO, RT_UNINTERRUPTIBLE);

        if (time > 0)
        {
            rt_tick_t time_tick = time;
            /* get the start tick of timer */
            before_sleep = rt_tick_get();

            /* init thread timer and start it */
            rt_timer_control(&(thread->thread_timer),
                             RT_TIMER_CTRL_SET_TIME,
                             &time_tick);
            rt_timer_start(&(thread->thread_timer));
        }

        /* enable interrupt */
        rt_spin_unlock_irqrestore(&(mp->spinlock), level);

        /* do a schedule */
        rt_schedule();

        if (thread->error != RT_EOK)
            return RT_NULL;

        if (time > 0)
        {