drivers/mmc/card/queue.c - maze/linux - Git at Google

 /*
  *  linux/drivers/mmc/queue.c
  *
  *  Copyright (C) 2003 Russell King, All Rights Reserved.
  *  Copyright 2006-2007 Pierre Ossman
  *
  * 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 "queue.h"

 #define MMC_QUEUE_BOUNCESZ	65536

 #define MMC_QUEUE_SUSPENDED	(1 << 0)

 /*
  * Prepare a MMC request. This just filters out odd stuff.
  */
 static int mmc_prep_request(struct request_queue *q, struct request *req)
 {
 	/*
 	 * We only like normal block requests.
 	 */
 	if (!blk_fs_request(req) && !blk_pc_request(req)) {
 		blk_dump_rq_flags(req, "MMC bad request");
 		return BLKPREP_KILL;
 	}

 	req->cmd_flags |= REQ_DONTPREP;

 	return BLKPREP_OK;
 }

 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;
 	unsigned int bouncesz;

 	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;

 	mq->queue->queuedata = mq;
 	mq->req = NULL;

 	blk_queue_prep_rq(mq->queue, mmc_prep_request);

 #ifdef CONFIG_MMC_BLOCK_BOUNCE
 	if (host->max_hw_segs == 1) {
 		bouncesz = MMC_QUEUE_BOUNCESZ;

 		if (bouncesz > host->max_req_size)
 			bouncesz = host->max_req_size;
 		if (bouncesz > host->max_seg_size)
 			bouncesz = host->max_seg_size;

 		mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
 		if (!mq->bounce_buf) {
 			printk(KERN_WARNING "%s: unable to allocate "
 				"bounce buffer\n", mmc_card_name(card));
 		} else {
 			blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
 			blk_queue_max_sectors(mq->queue, bouncesz / 512);
 			blk_queue_max_phys_segments(mq->queue, bouncesz / 512);
 			blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
 			blk_queue_max_segment_size(mq->queue, bouncesz);

 			mq->sg = kmalloc(sizeof(struct scatterlist),
 				GFP_KERNEL);
 			if (!mq->sg) {
 				ret = -ENOMEM;
 				goto free_bounce_buf;
 			}

 			mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
 				bouncesz / 512, GFP_KERNEL);
 			if (!mq->bounce_sg) {
 				ret = -ENOMEM;
 				goto free_sg;
 			}
 		}
 	}
 #endif

 	if (!mq->bounce_buf) {
 		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->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_bounce_sg;
 	}

 	return 0;
  free_bounce_sg:
  	if (mq->bounce_sg)
  		kfree(mq->bounce_sg);
  	mq->bounce_sg = NULL;
  free_sg:
 	kfree(mq->sg);
 	mq->sg = NULL;
  free_bounce_buf:
 	if (mq->bounce_buf)
 		kfree(mq->bounce_buf);
 	mq->bounce_buf = NULL;
  cleanup_queue:
 	blk_cleanup_queue(mq->queue);
 	return ret;
 }

 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);

 	/* Make sure the queue isn't suspended, as that will deadlock */
 	mmc_queue_resume(mq);

 	/* Then terminate our worker thread */
 	kthread_stop(mq->thread);

  	if (mq->bounce_sg)
  		kfree(mq->bounce_sg);
  	mq->bounce_sg = NULL;

 	kfree(mq->sg);
 	mq->sg = NULL;

 	if (mq->bounce_buf)
 		kfree(mq->bounce_buf);
 	mq->bounce_buf = 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);
 	}
 }

 /**
  * 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);
 	}
 }

 static void copy_sg(struct scatterlist *dst, unsigned int dst_len,
 	struct scatterlist *src, unsigned int src_len)
 {
 	unsigned int chunk;
 	char *dst_buf, *src_buf;
 	unsigned int dst_size, src_size;

 	dst_buf = NULL;
 	src_buf = NULL;
 	dst_size = 0;
 	src_size = 0;

 	while (src_len) {
 		BUG_ON(dst_len == 0);

 		if (dst_size == 0) {
 			dst_buf = page_address(dst->page) + dst->offset;
 			dst_size = dst->length;
 		}

 		if (src_size == 0) {
 			src_buf = page_address(src->page) + src->offset;
 			src_size = src->length;
 		}

 		chunk = min(dst_size, src_size);

 		memcpy(dst_buf, src_buf, chunk);

 		dst_buf += chunk;
 		src_buf += chunk;
 		dst_size -= chunk;
 		src_size -= chunk;

 		if (dst_size == 0) {
 			dst++;
 			dst_len--;
 		}

 		if (src_size == 0) {
 			src++;
 			src_len--;
 		}
 	}
 }

 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
 {
 	unsigned int sg_len;

 	if (!mq->bounce_buf)
 		return blk_rq_map_sg(mq->queue, mq->req, mq->sg);

 	BUG_ON(!mq->bounce_sg);

 	sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);

 	mq->bounce_sg_len = sg_len;

 	/*
 	 * Shortcut in the event we only get a single entry.
 	 */
 	if (sg_len == 1) {
 		memcpy(mq->sg, mq->bounce_sg, sizeof(struct scatterlist));
 		return 1;
 	}

 	mq->sg[0].page = virt_to_page(mq->bounce_buf);
 	mq->sg[0].offset = offset_in_page(mq->bounce_buf);
 	mq->sg[0].length = 0;

 	while (sg_len) {
 		mq->sg[0].length += mq->bounce_sg[sg_len - 1].length;
 		sg_len--;
 	}

 	return 1;
 }

 void mmc_queue_bounce_pre(struct mmc_queue *mq)
 {
 	if (!mq->bounce_buf)
 		return;

 	if (mq->bounce_sg_len == 1)
 		return;
 	if (rq_data_dir(mq->req) != WRITE)
 		return;

 	copy_sg(mq->sg, 1, mq->bounce_sg, mq->bounce_sg_len);
 }

 void mmc_queue_bounce_post(struct mmc_queue *mq)
 {
 	if (!mq->bounce_buf)
 		return;

 	if (mq->bounce_sg_len == 1)
 		return;
 	if (rq_data_dir(mq->req) != READ)
 		return;

 	copy_sg(mq->bounce_sg, mq->bounce_sg_len, mq->sg, 1);
 }
	/*
	* linux/drivers/mmc/queue.c
	*
	* Copyright (C) 2003 Russell King, All Rights Reserved.
	* Copyright 2006-2007 Pierre Ossman
	*
	* 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 "queue.h"

	#define MMC_QUEUE_BOUNCESZ 65536

	#define MMC_QUEUE_SUSPENDED (1 << 0)

	/*
	* Prepare a MMC request. This just filters out odd stuff.
	*/
	static int mmc_prep_request(struct request_queue q, struct request req)
	{
	/*
	* We only like normal block requests.
	*/
	if (!blk_fs_request(req) && !blk_pc_request(req)) {
	blk_dump_rq_flags(req, "MMC bad request");
	return BLKPREP_KILL;
	}

	req->cmd_flags \|= REQ_DONTPREP;

	return BLKPREP_OK;
	}

	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;
	unsigned int bouncesz;

	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;

	mq->queue->queuedata = mq;
	mq->req = NULL;

	blk_queue_prep_rq(mq->queue, mmc_prep_request);

	#ifdef CONFIG_MMC_BLOCK_BOUNCE
	if (host->max_hw_segs == 1) {
	bouncesz = MMC_QUEUE_BOUNCESZ;

	if (bouncesz > host->max_req_size)
	bouncesz = host->max_req_size;
	if (bouncesz > host->max_seg_size)
	bouncesz = host->max_seg_size;

	mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
	if (!mq->bounce_buf) {
	printk(KERN_WARNING "%s: unable to allocate "
	"bounce buffer\n", mmc_card_name(card));
	} else {
	blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
	blk_queue_max_sectors(mq->queue, bouncesz / 512);
	blk_queue_max_phys_segments(mq->queue, bouncesz / 512);
	blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
	blk_queue_max_segment_size(mq->queue, bouncesz);

	mq->sg = kmalloc(sizeof(struct scatterlist),
	GFP_KERNEL);
	if (!mq->sg) {
	ret = -ENOMEM;
	goto free_bounce_buf;
	}

	mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
	bouncesz / 512, GFP_KERNEL);
	if (!mq->bounce_sg) {
	ret = -ENOMEM;
	goto free_sg;
	}
	}
	}
	#endif

	if (!mq->bounce_buf) {
	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->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_bounce_sg;
	}

	return 0;
	free_bounce_sg:
	if (mq->bounce_sg)
	kfree(mq->bounce_sg);
	mq->bounce_sg = NULL;
	free_sg:
	kfree(mq->sg);
	mq->sg = NULL;
	free_bounce_buf:
	if (mq->bounce_buf)
	kfree(mq->bounce_buf);
	mq->bounce_buf = NULL;
	cleanup_queue:
	blk_cleanup_queue(mq->queue);
	return ret;
	}

	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);

	/* Make sure the queue isn't suspended, as that will deadlock */
	mmc_queue_resume(mq);

	/* Then terminate our worker thread */
	kthread_stop(mq->thread);

	if (mq->bounce_sg)
	kfree(mq->bounce_sg);
	mq->bounce_sg = NULL;

	kfree(mq->sg);
	mq->sg = NULL;

	if (mq->bounce_buf)
	kfree(mq->bounce_buf);
	mq->bounce_buf = 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);
	}
	}

	/**
	* 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);
	}
	}

	static void copy_sg(struct scatterlist *dst, unsigned int dst_len,
	struct scatterlist *src, unsigned int src_len)
	{
	unsigned int chunk;
	char dst_buf, src_buf;
	unsigned int dst_size, src_size;

	dst_buf = NULL;
	src_buf = NULL;
	dst_size = 0;
	src_size = 0;

	while (src_len) {
	BUG_ON(dst_len == 0);

	if (dst_size == 0) {
	dst_buf = page_address(dst->page) + dst->offset;
	dst_size = dst->length;
	}

	if (src_size == 0) {
	src_buf = page_address(src->page) + src->offset;
	src_size = src->length;
	}

	chunk = min(dst_size, src_size);

	memcpy(dst_buf, src_buf, chunk);

	dst_buf += chunk;
	src_buf += chunk;
	dst_size -= chunk;
	src_size -= chunk;

	if (dst_size == 0) {
	dst++;
	dst_len--;
	}

	if (src_size == 0) {
	src++;
	src_len--;
	}
	}
	}

	unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
	{
	unsigned int sg_len;

	if (!mq->bounce_buf)
	return blk_rq_map_sg(mq->queue, mq->req, mq->sg);

	BUG_ON(!mq->bounce_sg);

	sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);

	mq->bounce_sg_len = sg_len;

	/*
	* Shortcut in the event we only get a single entry.
	*/
	if (sg_len == 1) {
	memcpy(mq->sg, mq->bounce_sg, sizeof(struct scatterlist));
	return 1;
	}

	mq->sg[0].page = virt_to_page(mq->bounce_buf);
	mq->sg[0].offset = offset_in_page(mq->bounce_buf);
	mq->sg[0].length = 0;

	while (sg_len) {
	mq->sg[0].length += mq->bounce_sg[sg_len - 1].length;
	sg_len--;
	}

	return 1;
	}

	void mmc_queue_bounce_pre(struct mmc_queue *mq)
	{
	if (!mq->bounce_buf)
	return;

	if (mq->bounce_sg_len == 1)
	return;
	if (rq_data_dir(mq->req) != WRITE)
	return;

	copy_sg(mq->sg, 1, mq->bounce_sg, mq->bounce_sg_len);
	}

	void mmc_queue_bounce_post(struct mmc_queue *mq)
	{
	if (!mq->bounce_buf)
	return;

	if (mq->bounce_sg_len == 1)
	return;
	if (rq_data_dir(mq->req) != READ)
	return;

	copy_sg(mq->bounce_sg, mq->bounce_sg_len, mq->sg, 1);
	}