Re: [PATCH v2 04/16] mmc: meson-gx: use _irqsave variant of spinlock

[Ulf Hansson]

On 21 August 2017 at 18:02, Jerome Brunet <jbrunet@xxxxxxxxxxxx> wrote:
> spinlock used in interrupt handler should use the _irqsave variant

Exactly why is that needed?

>
> Fixes: 51c5d8447bd7 ("MMC: meson: initial support for GX platforms")
> Reviewed-by: Kevin Hilman <khilman@xxxxxxxxxxxx>
> Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
> ---
>  drivers/mmc/host/meson-gx-mmc.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
> index 8a74a048db88..a399fbd415f4 100644
> --- a/drivers/mmc/host/meson-gx-mmc.c
> +++ b/drivers/mmc/host/meson-gx-mmc.c
> @@ -727,6 +727,7 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
>         struct mmc_command *cmd;
>         struct mmc_data *data;
>         u32 irq_en, status, raw_status;
> +       unsigned long flag;
>         irqreturn_t ret = IRQ_HANDLED;
>
>         if (WARN_ON(!host))
> @@ -739,7 +740,7 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
>
>         data = cmd->data;
>
> -       spin_lock(&host->lock);
> +       spin_lock_irqsave(&host->lock, flag);
>         irq_en = readl(host->regs + SD_EMMC_IRQ_EN);
>         raw_status = readl(host->regs + SD_EMMC_STATUS);
>         status = raw_status & irq_en;
> @@ -806,7 +807,7 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
>         if (ret == IRQ_HANDLED)
>                 meson_mmc_request_done(host->mmc, cmd->mrq);
>
> -       spin_unlock(&host->lock);
> +       spin_unlock_irqrestore(&host->lock, flag);
>         return ret;
>  }
>
> --
> 2.9.5
>

Kind regards
Uffe