/* *  linux/drivers/mmc/mmc_queue.c * *  Copyright (C) 2003 Russell King, All Rights Reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * */#include <linux/module.h>#include <linux/blkdev.h>#include <linux/kthread.h> #include <linux/mmc/card.h>#include <linux/mmc/host.h>#include "mmc_queue.h" #define MMC_QUEUE_SUSPENDED	(1 << 0) /* * Prepare a MMC request.  Essentially, this means passing the * preparation off to the media driver.  The media driver will * create a mmc_io_request in req->special. */static int mmc_prep_request(struct request_queue *q, struct request *req){	struct mmc_queue *mq = q->queuedata;	int ret = BLKPREP_KILL; 	if (blk_special_request(req)) {		/*		 * Special commands already have the command		 * blocks already setup in req->special.		 */		BUG_ON(!req->special); 		ret = BLKPREP_OK;	} else if (blk_fs_request(req) || blk_pc_request(req)) {		/*		 * Block I/O requests need translating according		 * to the protocol.		 */		ret = mq->prep_fn(mq, req);	} else {		/*		 * Everything else is invalid.		 */		blk_dump_rq_flags(req, "MMC bad request");	} 	if (ret == BLKPREP_OK)		req->cmd_flags |= REQ_DONTPREP; 	return ret;} static int mmc_queue_thread(void *d){	struct mmc_queue *mq = d;	struct request_queue *q = mq->queue; 	/*	 * Set iothread to ensure that we aren't put to sleep by	 * the process freezing.  We handle suspension ourselves.	 */	current->flags |= PF_MEMALLOC|PF_NOFREEZE; 	down(&mq->thread_sem);	do {		struct request *req = NULL; 		spin_lock_irq(q->queue_lock);		set_current_state(TASK_INTERRUPTIBLE);		if (!blk_queue_plugged(q))			req = elv_next_request(q);		mq->req = req;		spin_unlock_irq(q->queue_lock); 		if (!req) {			if (kthread_should_stop()) {				set_current_state(TASK_RUNNING);				break;			}			up(&mq->thread_sem);			schedule();			down(&mq->thread_sem);			continue;		}		set_current_state(TASK_RUNNING); 		mq->issue_fn(mq, req);	} while (1);	up(&mq->thread_sem); 	return 0;} /* * Generic MMC request handler.  This is called for any queue on a * particular host.  When the host is not busy, we look for a request * on any queue on this host, and attempt to issue it.  This may * not be the queue we were asked to process. */static void mmc_request(request_queue_t *q){	struct mmc_queue *mq = q->queuedata;	struct request *req;	int ret; 	if (!mq) {		printk(KERN_ERR "MMC: killing requests for dead queue\n");		while ((req = elv_next_request(q)) != NULL) {			do {				ret = end_that_request_chunk(req, 0,					req->current_nr_sectors << 9);			} while (ret);		}		return;	} 	if (!mq->req)		wake_up_process(mq->thread);} /** * mmc_init_queue - initialise a queue structure. * @mq: mmc queue * @card: mmc card to attach this queue * @lock: queue lock * * Initialise a MMC card request queue. */int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock){	struct mmc_host *host = card->host;	u64 limit = BLK_BOUNCE_HIGH;	int ret; 	if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)		limit = *mmc_dev(host)->dma_mask; 	mq->card = card;	mq->queue = blk_init_queue(mmc_request, lock);	if (!mq->queue)		return -ENOMEM; 	blk_queue_prep_rq(mq->queue, mmc_prep_request);	blk_queue_bounce_limit(mq->queue, limit);	blk_queue_max_sectors(mq->queue, host->max_req_size / 512);	blk_queue_max_phys_segments(mq->queue, host->max_phys_segs);	blk_queue_max_hw_segments(mq->queue, host->max_hw_segs);	blk_queue_max_segment_size(mq->queue, host->max_seg_size); 	mq->queue->queuedata = mq;	mq->req = NULL; 	mq->sg = kmalloc(sizeof(struct scatterlist) * host->max_phys_segs,			 GFP_KERNEL);	if (!mq->sg) {		ret = -ENOMEM;		goto cleanup_queue;	} 	init_MUTEX(&mq->thread_sem); 	mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");	if (IS_ERR(mq->thread)) {		ret = PTR_ERR(mq->thread);		goto free_sg;	} 	return 0;  free_sg:	kfree(mq->sg);	mq->sg = NULL; cleanup_queue:	blk_cleanup_queue(mq->queue);	return ret;}EXPORT_SYMBOL(mmc_init_queue); void mmc_cleanup_queue(struct mmc_queue *mq){	request_queue_t *q = mq->queue;	unsigned long flags; 	/* Mark that we should start throwing out stragglers */	spin_lock_irqsave(q->queue_lock, flags);	q->queuedata = NULL;	spin_unlock_irqrestore(q->queue_lock, flags); 	/* Then terminate our worker thread */	kthread_stop(mq->thread); 	kfree(mq->sg);	mq->sg = NULL; 	blk_cleanup_queue(mq->queue); 	mq->card = NULL;}EXPORT_SYMBOL(mmc_cleanup_queue); /** * mmc_queue_suspend - suspend a MMC request queue * @mq: MMC queue to suspend * * Stop the block request queue, and wait for our thread to * complete any outstanding requests.  This ensures that we * won't suspend while a request is being processed. */void mmc_queue_suspend(struct mmc_queue *mq){	request_queue_t *q = mq->queue;	unsigned long flags; 	if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {		mq->flags |= MMC_QUEUE_SUSPENDED; 		spin_lock_irqsave(q->queue_lock, flags);		blk_stop_queue(q);		spin_unlock_irqrestore(q->queue_lock, flags); 		down(&mq->thread_sem);	}}EXPORT_SYMBOL(mmc_queue_suspend); /** * mmc_queue_resume - resume a previously suspended MMC request queue * @mq: MMC queue to resume */void mmc_queue_resume(struct mmc_queue *mq){	request_queue_t *q = mq->queue;	unsigned long flags; 	if (mq->flags & MMC_QUEUE_SUSPENDED) {		mq->flags &= ~MMC_QUEUE_SUSPENDED; 		up(&mq->thread_sem); 		spin_lock_irqsave(q->queue_lock, flags);		blk_start_queue(q);		spin_unlock_irqrestore(q->queue_lock, flags);	}}EXPORT_SYMBOL(mmc_queue_resume);