Re: [PATCH v2] mmc: sdhci-pxav3: fix race between runtime pm and irq

From: Ulf Hansson
Date: Fri Jan 23 2015 - 06:55:11 EST


On 23 January 2015 at 11:08, Jisheng Zhang <jszhang@xxxxxxxxxxx> wrote:
> This patch is to fix a race condition that may cause an unhandled irq,
> which results in big sdhci interrupt numbers and endless "mmc1: got irq
> while runtime suspended" msgs before v3.15.
>
> Consider following scenario:
>
> CPU0 CPU1
> sdhci_pxav3_runtime_suspend()
> spin_lock_irqsave(&host->lock, flags);
> sdhci_irq()
> spining on the &host->lock
> host->runtime_suspended = true;
> spin_unlock_irqrestore(&host->lock, flags);
> get the &host->lock
> runtime_suspended is true now
> return IRQ_NONE;
>
> Fix this race by using the core sdhci.c supplied sdhci_runtime_suspend_host()
> in runtime suspend hook which will disable card interrupts. We also use the
> sdhci_runtime_resume_host() in the runtime resume hook accordingly.
>
> Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # v3.9+

Thanks! Applied for next.

Kind regards
Uffe

> ---
> Changes in v2:
> return ret once sdhci_runtime_suspend_host() gives an error
> drivers/mmc/host/sdhci-pxav3.c | 15 +++++----------
> 1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c
> index 4de39fb..e2817cc 100644
> --- a/drivers/mmc/host/sdhci-pxav3.c
> +++ b/drivers/mmc/host/sdhci-pxav3.c
> @@ -460,11 +460,11 @@ static int sdhci_pxav3_runtime_suspend(struct device *dev)
> struct sdhci_host *host = dev_get_drvdata(dev);
> struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> struct sdhci_pxa *pxa = pltfm_host->priv;
> - unsigned long flags;
> + int ret;
>
> - spin_lock_irqsave(&host->lock, flags);
> - host->runtime_suspended = true;
> - spin_unlock_irqrestore(&host->lock, flags);
> + ret = sdhci_runtime_suspend_host(host);
> + if (ret)
> + return ret;
>
> clk_disable_unprepare(pxa->clk_io);
> if (!IS_ERR(pxa->clk_core))
> @@ -478,17 +478,12 @@ static int sdhci_pxav3_runtime_resume(struct device *dev)
> struct sdhci_host *host = dev_get_drvdata(dev);
> struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> struct sdhci_pxa *pxa = pltfm_host->priv;
> - unsigned long flags;
>
> clk_prepare_enable(pxa->clk_io);
> if (!IS_ERR(pxa->clk_core))
> clk_prepare_enable(pxa->clk_core);
>
> - spin_lock_irqsave(&host->lock, flags);
> - host->runtime_suspended = false;
> - spin_unlock_irqrestore(&host->lock, flags);
> -
> - return 0;
> + return sdhci_runtime_resume_host(host);
> }
> #endif
>
> --
> 2.1.4
>
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