397 lines
8.4 KiB
C
397 lines
8.4 KiB
C
/*
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* linux/drivers/mmc/queue.c
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*
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* Copyright (C) 2003 Russell King, All Rights Reserved.
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* Copyright 2006-2007 Pierre Ossman
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/module.h>
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#include <linux/blkdev.h>
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#include <linux/kthread.h>
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#include <linux/mmc/card.h>
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#include <linux/mmc/host.h>
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#include "queue.h"
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#define MMC_QUEUE_BOUNCESZ 65536
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#define MMC_QUEUE_SUSPENDED (1 << 0)
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/*
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* Prepare a MMC request. This just filters out odd stuff.
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*/
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static int mmc_prep_request(struct request_queue *q, struct request *req)
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{
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/*
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* We only like normal block requests.
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*/
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if (!blk_fs_request(req) && !blk_pc_request(req)) {
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blk_dump_rq_flags(req, "MMC bad request");
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return BLKPREP_KILL;
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}
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req->cmd_flags |= REQ_DONTPREP;
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return BLKPREP_OK;
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}
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static int mmc_queue_thread(void *d)
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{
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struct mmc_queue *mq = d;
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struct request_queue *q = mq->queue;
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/*
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* Set iothread to ensure that we aren't put to sleep by
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* the process freezing. We handle suspension ourselves.
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*/
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current->flags |= PF_MEMALLOC|PF_NOFREEZE;
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down(&mq->thread_sem);
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do {
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struct request *req = NULL;
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spin_lock_irq(q->queue_lock);
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set_current_state(TASK_INTERRUPTIBLE);
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if (!blk_queue_plugged(q))
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req = elv_next_request(q);
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mq->req = req;
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spin_unlock_irq(q->queue_lock);
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if (!req) {
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if (kthread_should_stop()) {
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set_current_state(TASK_RUNNING);
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break;
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}
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up(&mq->thread_sem);
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schedule();
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down(&mq->thread_sem);
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continue;
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}
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set_current_state(TASK_RUNNING);
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mq->issue_fn(mq, req);
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} while (1);
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up(&mq->thread_sem);
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return 0;
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}
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/*
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* Generic MMC request handler. This is called for any queue on a
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* particular host. When the host is not busy, we look for a request
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* on any queue on this host, and attempt to issue it. This may
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* not be the queue we were asked to process.
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*/
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static void mmc_request(request_queue_t *q)
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{
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struct mmc_queue *mq = q->queuedata;
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struct request *req;
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int ret;
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if (!mq) {
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printk(KERN_ERR "MMC: killing requests for dead queue\n");
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while ((req = elv_next_request(q)) != NULL) {
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do {
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ret = end_that_request_chunk(req, 0,
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req->current_nr_sectors << 9);
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} while (ret);
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}
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return;
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}
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if (!mq->req)
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wake_up_process(mq->thread);
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}
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/**
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* mmc_init_queue - initialise a queue structure.
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* @mq: mmc queue
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* @card: mmc card to attach this queue
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* @lock: queue lock
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*
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* Initialise a MMC card request queue.
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*/
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int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock)
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{
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struct mmc_host *host = card->host;
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u64 limit = BLK_BOUNCE_HIGH;
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int ret;
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unsigned int bouncesz;
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if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
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limit = *mmc_dev(host)->dma_mask;
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mq->card = card;
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mq->queue = blk_init_queue(mmc_request, lock);
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if (!mq->queue)
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return -ENOMEM;
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mq->queue->queuedata = mq;
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mq->req = NULL;
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blk_queue_prep_rq(mq->queue, mmc_prep_request);
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#ifdef CONFIG_MMC_BLOCK_BOUNCE
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if (host->max_hw_segs == 1) {
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bouncesz = MMC_QUEUE_BOUNCESZ;
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if (bouncesz > host->max_req_size)
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bouncesz = host->max_req_size;
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if (bouncesz > host->max_seg_size)
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bouncesz = host->max_seg_size;
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mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
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if (!mq->bounce_buf) {
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printk(KERN_WARNING "%s: unable to allocate "
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"bounce buffer\n", mmc_card_name(card));
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} else {
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blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
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blk_queue_max_sectors(mq->queue, bouncesz / 512);
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blk_queue_max_phys_segments(mq->queue, bouncesz / 512);
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blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
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blk_queue_max_segment_size(mq->queue, bouncesz);
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mq->sg = kmalloc(sizeof(struct scatterlist),
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GFP_KERNEL);
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if (!mq->sg) {
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ret = -ENOMEM;
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goto free_bounce_buf;
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}
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mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
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bouncesz / 512, GFP_KERNEL);
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if (!mq->bounce_sg) {
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ret = -ENOMEM;
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goto free_sg;
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}
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}
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}
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#endif
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if (!mq->bounce_buf) {
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blk_queue_bounce_limit(mq->queue, limit);
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blk_queue_max_sectors(mq->queue, host->max_req_size / 512);
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blk_queue_max_phys_segments(mq->queue, host->max_phys_segs);
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blk_queue_max_hw_segments(mq->queue, host->max_hw_segs);
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blk_queue_max_segment_size(mq->queue, host->max_seg_size);
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mq->sg = kmalloc(sizeof(struct scatterlist) *
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host->max_phys_segs, GFP_KERNEL);
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if (!mq->sg) {
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ret = -ENOMEM;
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goto cleanup_queue;
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}
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}
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init_MUTEX(&mq->thread_sem);
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mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");
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if (IS_ERR(mq->thread)) {
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ret = PTR_ERR(mq->thread);
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goto free_bounce_sg;
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}
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return 0;
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free_bounce_sg:
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if (mq->bounce_sg)
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kfree(mq->bounce_sg);
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mq->bounce_sg = NULL;
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free_sg:
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kfree(mq->sg);
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mq->sg = NULL;
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free_bounce_buf:
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if (mq->bounce_buf)
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kfree(mq->bounce_buf);
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mq->bounce_buf = NULL;
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cleanup_queue:
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blk_cleanup_queue(mq->queue);
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return ret;
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}
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void mmc_cleanup_queue(struct mmc_queue *mq)
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{
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request_queue_t *q = mq->queue;
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unsigned long flags;
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/* Mark that we should start throwing out stragglers */
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spin_lock_irqsave(q->queue_lock, flags);
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q->queuedata = NULL;
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spin_unlock_irqrestore(q->queue_lock, flags);
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/* Make sure the queue isn't suspended, as that will deadlock */
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mmc_queue_resume(mq);
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/* Then terminate our worker thread */
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kthread_stop(mq->thread);
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if (mq->bounce_sg)
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kfree(mq->bounce_sg);
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mq->bounce_sg = NULL;
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kfree(mq->sg);
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mq->sg = NULL;
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if (mq->bounce_buf)
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kfree(mq->bounce_buf);
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mq->bounce_buf = NULL;
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blk_cleanup_queue(mq->queue);
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mq->card = NULL;
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}
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EXPORT_SYMBOL(mmc_cleanup_queue);
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/**
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* mmc_queue_suspend - suspend a MMC request queue
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* @mq: MMC queue to suspend
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*
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* Stop the block request queue, and wait for our thread to
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* complete any outstanding requests. This ensures that we
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* won't suspend while a request is being processed.
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*/
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void mmc_queue_suspend(struct mmc_queue *mq)
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{
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request_queue_t *q = mq->queue;
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unsigned long flags;
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if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
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mq->flags |= MMC_QUEUE_SUSPENDED;
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spin_lock_irqsave(q->queue_lock, flags);
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blk_stop_queue(q);
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spin_unlock_irqrestore(q->queue_lock, flags);
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down(&mq->thread_sem);
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}
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}
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/**
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* mmc_queue_resume - resume a previously suspended MMC request queue
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* @mq: MMC queue to resume
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*/
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void mmc_queue_resume(struct mmc_queue *mq)
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{
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request_queue_t *q = mq->queue;
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unsigned long flags;
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if (mq->flags & MMC_QUEUE_SUSPENDED) {
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mq->flags &= ~MMC_QUEUE_SUSPENDED;
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up(&mq->thread_sem);
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spin_lock_irqsave(q->queue_lock, flags);
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blk_start_queue(q);
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spin_unlock_irqrestore(q->queue_lock, flags);
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}
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}
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static void copy_sg(struct scatterlist *dst, unsigned int dst_len,
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struct scatterlist *src, unsigned int src_len)
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{
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unsigned int chunk;
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char *dst_buf, *src_buf;
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unsigned int dst_size, src_size;
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dst_buf = NULL;
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src_buf = NULL;
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dst_size = 0;
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src_size = 0;
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while (src_len) {
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BUG_ON(dst_len == 0);
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if (dst_size == 0) {
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dst_buf = page_address(dst->page) + dst->offset;
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dst_size = dst->length;
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}
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if (src_size == 0) {
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src_buf = page_address(src->page) + src->offset;
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src_size = src->length;
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}
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chunk = min(dst_size, src_size);
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memcpy(dst_buf, src_buf, chunk);
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dst_buf += chunk;
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src_buf += chunk;
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dst_size -= chunk;
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src_size -= chunk;
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if (dst_size == 0) {
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dst++;
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dst_len--;
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}
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if (src_size == 0) {
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src++;
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src_len--;
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}
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}
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}
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unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
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{
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unsigned int sg_len;
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if (!mq->bounce_buf)
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return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
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BUG_ON(!mq->bounce_sg);
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sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
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mq->bounce_sg_len = sg_len;
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/*
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* Shortcut in the event we only get a single entry.
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*/
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if (sg_len == 1) {
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memcpy(mq->sg, mq->bounce_sg, sizeof(struct scatterlist));
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return 1;
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}
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mq->sg[0].page = virt_to_page(mq->bounce_buf);
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mq->sg[0].offset = offset_in_page(mq->bounce_buf);
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mq->sg[0].length = 0;
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while (sg_len) {
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mq->sg[0].length += mq->bounce_sg[sg_len - 1].length;
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sg_len--;
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}
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return 1;
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}
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void mmc_queue_bounce_pre(struct mmc_queue *mq)
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{
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if (!mq->bounce_buf)
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return;
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if (mq->bounce_sg_len == 1)
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return;
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if (rq_data_dir(mq->req) != WRITE)
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return;
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copy_sg(mq->sg, 1, mq->bounce_sg, mq->bounce_sg_len);
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}
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void mmc_queue_bounce_post(struct mmc_queue *mq)
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{
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if (!mq->bounce_buf)
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return;
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if (mq->bounce_sg_len == 1)
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return;
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if (rq_data_dir(mq->req) != READ)
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return;
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copy_sg(mq->bounce_sg, mq->bounce_sg_len, mq->sg, 1);
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}
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