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Commit b9269fdd authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Chris Ball
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mmc: tmio: fix recursive spinlock, don't schedule with interrupts disabled 



Calling mmc_request_done() under a spinlock with interrupts disabled
leads to a recursive spin-lock on request retry path and to
scheduling in atomic context. This patch fixes both these problems
by moving mmc_request_done() to the scheduler workqueue.

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 15bed0f2

drivers/mmc/host/tmio_mmc.h

+5 −1
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 


#include <linux/highmem.h>

#include <linux/mmc/tmio.h>

#include <linux/mutex.h>

#include <linux/pagemap.h>

#include <linux/spinlock.h>
@@ -73,8 +74,11 @@ struct tmio_mmc_host { 


	/* Track lost interrupts */

	struct delayed_work	delayed_reset_work;

	spinlock_t		lock;

	struct work_struct	done;



	spinlock_t		lock;		/* protect host private data */

	unsigned long		last_req_ts;

	struct mutex		ios_lock;	/* protect set_ios() context */

};



int tmio_mmc_host_probe(struct tmio_mmc_host **host,

drivers/mmc/host/tmio_mmc_pio.c

+29 −6
Original line number Diff line number Diff line
@@ -250,10 +250,16 @@ static void tmio_mmc_reset_work(struct work_struct *work) 
/* called with host->lock held, interrupts disabled */

static void tmio_mmc_finish_request(struct tmio_mmc_host *host)

{

	struct mmc_request *mrq = host->mrq;

	struct mmc_request *mrq;

	unsigned long flags;



	if (!mrq)

	spin_lock_irqsave(&host->lock, flags);



	mrq = host->mrq;

	if (IS_ERR_OR_NULL(mrq)) {

		spin_unlock_irqrestore(&host->lock, flags);

		return;

	}



	host->cmd = NULL;

	host->data = NULL;
@@ -262,11 +268,18 @@ static void tmio_mmc_finish_request(struct tmio_mmc_host *host) 
	cancel_delayed_work(&host->delayed_reset_work);



	host->mrq = NULL;

	spin_unlock_irqrestore(&host->lock, flags);



	/* FIXME: mmc_request_done() can schedule! */

	mmc_request_done(host->mmc, mrq);

}



static void tmio_mmc_done_work(struct work_struct *work)

{

	struct tmio_mmc_host *host = container_of(work, struct tmio_mmc_host,

						  done);

	tmio_mmc_finish_request(host);

}



/* These are the bitmasks the tmio chip requires to implement the MMC response

 * types. Note that R1 and R6 are the same in this scheme. */

#define APP_CMD        0x0040
@@ -433,7 +446,7 @@ void tmio_mmc_do_data_irq(struct tmio_mmc_host *host) 
			BUG();

	}



	tmio_mmc_finish_request(host);

	schedule_work(&host->done);

}



static void tmio_mmc_data_irq(struct tmio_mmc_host *host)
@@ -523,7 +536,7 @@ static void tmio_mmc_cmd_irq(struct tmio_mmc_host *host, 
				tasklet_schedule(&host->dma_issue);

		}

	} else {

		tmio_mmc_finish_request(host);

		schedule_work(&host->done);

	}



out:
@@ -573,6 +586,7 @@ irqreturn_t tmio_mmc_irq(int irq, void *devid) 
	if (ireg & (TMIO_STAT_CARD_INSERT | TMIO_STAT_CARD_REMOVE)) {

		tmio_mmc_ack_mmc_irqs(host, TMIO_STAT_CARD_INSERT |

			TMIO_STAT_CARD_REMOVE);

		if (!work_pending(&host->mmc->detect.work))

			mmc_detect_change(host->mmc, msecs_to_jiffies(100));

		goto out;

	}
@@ -703,6 +717,8 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) 
	struct tmio_mmc_data *pdata = host->pdata;

	unsigned long flags;



	mutex_lock(&host->ios_lock);



	spin_lock_irqsave(&host->lock, flags);

	if (host->mrq) {

		if (IS_ERR(host->mrq)) {
@@ -718,6 +734,8 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) 
				host->mrq->cmd->opcode, host->last_req_ts, jiffies);

		}

		spin_unlock_irqrestore(&host->lock, flags);



		mutex_unlock(&host->ios_lock);

		return;

	}
@@ -771,6 +789,8 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) 
			current->comm, task_pid_nr(current),

			ios->clock, ios->power_mode);

	host->mrq = NULL;



	mutex_unlock(&host->ios_lock);

}



static int tmio_mmc_get_ro(struct mmc_host *mmc)
@@ -867,9 +887,11 @@ int __devinit tmio_mmc_host_probe(struct tmio_mmc_host **host, 
		tmio_mmc_enable_sdio_irq(mmc, 0);



	spin_lock_init(&_host->lock);

	mutex_init(&_host->ios_lock);



	/* Init delayed work for request timeouts */

	INIT_DELAYED_WORK(&_host->delayed_reset_work, tmio_mmc_reset_work);

	INIT_WORK(&_host->done, tmio_mmc_done_work);



	/* See if we also get DMA */

	tmio_mmc_request_dma(_host, pdata);
@@ -917,6 +939,7 @@ void tmio_mmc_host_remove(struct tmio_mmc_host *host) 
		pm_runtime_get_sync(&pdev->dev);



	mmc_remove_host(host->mmc);

	cancel_work_sync(&host->done);

	cancel_delayed_work_sync(&host->delayed_reset_work);

	tmio_mmc_release_dma(host);