diff mbox

mmc: sdhci: fix possible scheduling while atomic

Message ID EEBFEDF8-5DC8-4DFC-B98B-F434DC323B9E@nvidia.com (mailing list archive)
State New, archived
Headers show

Commit Message

Philip Rakity Jan. 20, 2014, 3:03 p.m. UTC 
I have no way to test this problem but I was thinking along the lines of


regards,

Philip

On Jan 20, 2014, at 9:51 AM, Philip Rakity <prakity@nvidia.com> wrote:

> 
> Chris,
> 
> The suggested fix can lock out interrupts for up to 150ms.  There needs to be another way.
> So, I would strongly recommend we find another solution.
> 
> Philip
> 
> On Jan 17, 2014, at 7:57 PM, Andrew Bresticker <abrestic@chromium.org> wrote:
> 
>> sdhci_execute_tuning() takes host->lock without disabling interrupts.
>> Use spin_lock_irq{save,restore} instead so that we avoid taking an
>> interrupt and scheduling while holding host->lock.
>> 
>> Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
>> ---
>> drivers/mmc/host/sdhci.c | 13 +++++++------
>> 1 file changed, 7 insertions(+), 6 deletions(-)
>> 
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>> index ec3eb30..84c80e7 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -1857,12 +1857,13 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> 	unsigned long timeout;
>> 	int err = 0;
>> 	bool requires_tuning_nonuhs = false;
>> +	unsigned long flags;
>> 
>> 	host = mmc_priv(mmc);
>> 
>> 	sdhci_runtime_pm_get(host);
>> 	disable_irq(host->irq);
>> -	spin_lock(&host->lock);
>> +	spin_lock_irqsave(&host->lock, flags);
> 
> 
> The disable_irq() call stops the controller from doing interrupts.  
> Please explain what problem you are seeing
> 
>> 
>> 	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>> 
>> @@ -1882,14 +1883,14 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> 	    requires_tuning_nonuhs)
>> 		ctrl |= SDHCI_CTRL_EXEC_TUNING;
>> 	else {
>> -		spin_unlock(&host->lock);
>> +		spin_unlock_irqrestore(&host->lock, flags);
>> 		enable_irq(host->irq);
>> 		sdhci_runtime_pm_put(host);
>> 		return 0;
>> 	}
>> 
>> 	if (host->ops->platform_execute_tuning) {
>> -		spin_unlock(&host->lock);
>> +		spin_unlock_irqrestore(&host->lock, flags);
>> 		enable_irq(host->irq);
>> 		err = host->ops->platform_execute_tuning(host, opcode);
>> 		sdhci_runtime_pm_put(host);
>> @@ -1963,7 +1964,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> 		host->cmd = NULL;
>> 		host->mrq = NULL;
>> 
>> -		spin_unlock(&host->lock);
>> +		spin_unlock_irqrestore(&host->lock, flags);
>> 		enable_irq(host->irq);
>> 
>> 		/* Wait for Buffer Read Ready interrupt */
>> @@ -1971,7 +1972,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> 					(host->tuning_done == 1),
>> 					msecs_to_jiffies(50));
>> 		disable_irq(host->irq);
>> -		spin_lock(&host->lock);
>> +		spin_lock_irqsave(&host->lock, flags);
>> 
>> 		if (!host->tuning_done) {
>> 			pr_info(DRIVER_NAME ": Timeout waiting for "
>> @@ -2046,7 +2047,7 @@ out:
>> 		err = 0;
>> 
>> 	sdhci_clear_set_irqs(host, SDHCI_INT_DATA_AVAIL, ier);
>> -	spin_unlock(&host->lock);
>> +	spin_unlock_irqrestore(&host->lock, flags);
>> 	enable_irq(host->irq);
>> 	sdhci_runtime_pm_put(host);
>> 
>> -- 
>> 1.8.5.2
>> 
>> --
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diff mbox

Patch

--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1862,6 +1862,7 @@  static int sdhci_execute_tuning(struct mmc_host *mmc, u32 
 
        sdhci_runtime_pm_get(host);
        disable_irq(host->irq);
+       sdhci_disable_card_detection(host);
        spin_lock(&host->lock);
 
        ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
@@ -1883,6 +1884,7 @@  static int sdhci_execute_tuning(struct mmc_host *mmc, u32 
                ctrl |= SDHCI_CTRL_EXEC_TUNING;
        else {
                spin_unlock(&host->lock);
+               sdhci_enable_card_detection(host);
                enable_irq(host->irq);
                sdhci_runtime_pm_put(host);
                return 0;
@@ -1890,6 +1892,7 @@  static int sdhci_execute_tuning(struct mmc_host *mmc, u32 
 
        if (host->ops->platform_execute_tuning) {
                spin_unlock(&host->lock);
+               sdhci_enable_card_detection(host);
                enable_irq(host->irq);
                err = host->ops->platform_execute_tuning(host, opcode);
                sdhci_runtime_pm_put(host);
@@ -2047,6 +2050,7 @@  out:
 
        sdhci_clear_set_irqs(host, SDHCI_INT_DATA_AVAIL, ier);
        spin_unlock(&host->lock);
+       sdhci_enable_card_detection(host);
        enable_irq(host->irq);
        sdhci_runtime_pm_put(host);