Re: [PATCH/RFC] mmc: sh_mmcif: Add exclusion between cmd and interrupt

[Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>]

Hello.

On 02/15/2015 05:46 PM, Yoshihiro Kaneko wrote:

> From: Kouichi Tomita <kouichi.tomita.yn@renesas.com>

> A command end interrupt should not be processed between command issue
> and setting of wait_for flag. It expects already the flag to be set.
> Therefore the exclusive control was added.

> Signed-off-by: Kouichi Tomita <kouichi.tomita.yn@renesas.com>
> Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
> ---

> This patch is based on next branch of Chris Ball's mmc tree.

>   drivers/mmc/host/sh_mmcif.c | 11 ++++++++++-
>   1 file changed, 10 insertions(+), 1 deletion(-)

> diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
> index 7d9d6a3..e5d0b42 100644
> --- a/drivers/mmc/host/sh_mmcif.c
> +++ b/drivers/mmc/host/sh_mmcif.c
[...]
> @@ -1171,6 +1174,12 @@ static irqreturn_t sh_mmcif_irqt(int irq, void *dev_id)
>   	struct sh_mmcif_host *host = dev_id;
>   	struct mmc_request *mrq;
>   	bool wait = false;
> +	unsigned long flags;
> +	int wait_work;
> +
> +	spin_lock_irqsave(&host->lock, flags);
> +	wait_work = host->wait_for;
> +	spin_unlock_irqrestore(&host->lock, flags);

    Locking don't seem to have much sense here, as the read is already atomic.

WBR, Sergei