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mmc: tmio: fix recursive spinlock, don't schedule with interrupts disabled

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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: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Guennadi Liakhovetski 2011-07-14 12:12:38 +02:00 committed by Chris Ball
parent 15bed0f2fa
commit b9269fdd4f
2 changed files with 34 additions and 7 deletions
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6
drivers/mmc/host/tmio_mmc.h
View file

@ -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,

35
drivers/mmc/host/tmio_mmc_pio.c
View file

@ -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:
@ -573,7 +586,8 @@ 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);
mmc_detect_change(host->mmc, msecs_to_jiffies(100));
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);