mmc_hostname(host), mrq->cmd->opcode,
                 mrq->cmd->arg, mrq->cmd->flags);
 
-       WARN_ON(host->card_busy == NULL);
+       WARN_ON(!host->claimed);
 
        mrq->cmd->error = 0;
        mrq->cmd->mrq = mrq;
 {
        struct mmc_request mrq;
 
-       BUG_ON(host->card_busy == NULL);
+       BUG_ON(!host->claimed);
 
        memset(&mrq, 0, sizeof(struct mmc_request));
 
 
        int i, err;
 
-       BUG_ON(host->card_busy == NULL);
+       BUG_ON(!host->claimed);
        BUG_ON(retries < 0);
 
        err = MMC_ERR_INVALID;
        spin_lock_irqsave(&host->lock, flags);
        while (1) {
                set_current_state(TASK_UNINTERRUPTIBLE);
-               if (host->card_busy == NULL)
+               if (!host->claimed)
                        break;
                spin_unlock_irqrestore(&host->lock, flags);
                schedule();
                spin_lock_irqsave(&host->lock, flags);
        }
        set_current_state(TASK_RUNNING);
-       host->card_busy = card;
+       host->claimed = 1;
        spin_unlock_irqrestore(&host->lock, flags);
        remove_wait_queue(&host->wq, &wait);
 
 {
        unsigned long flags;
 
-       BUG_ON(host->card_busy == NULL);
+       BUG_ON(!host->claimed);
 
        spin_lock_irqsave(&host->lock, flags);
-       host->card_busy = NULL;
+       host->claimed = 0;
        spin_unlock_irqrestore(&host->lock, flags);
 
        wake_up(&host->wq);
        int err;
        struct mmc_command cmd;
 
-       BUG_ON(host->card_busy == NULL);
+       BUG_ON(!host->claimed);
 
        if (host->card_selected == card)
                return MMC_ERR_NONE;
 
        struct list_head        cards;          /* devices attached to this host */
 
        wait_queue_head_t       wq;
-       spinlock_t              lock;           /* card_busy lock */
-       struct mmc_card         *card_busy;     /* the MMC card claiming host */
+       spinlock_t              lock;           /* claimed lock */
+       unsigned int            claimed:1;      /* host exclusively claimed */
+
        struct mmc_card         *card_selected; /* the selected MMC card */
 
        struct delayed_work     detect;