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/*
* 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_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;
}
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);
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);
}
}
/**
* 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);
}
}
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