linux-kernel - Re: [PATCH 9/9] omap mmc host: Use disable_irq

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Date:	Sun, 26 Apr 2009 21:21:18 +0200
From:	Pierre Ossman <pierre@...man.eu>
To:	Carlos Aguiar <carlos.aguiar@...t.org.br>,
	Anderson Briglia <briglia.anderson@...il.com>,
	"Syed Mohammed, Khasim" <x0khasim@...com>
Cc:	Ben Nizette <bn@...sdigital.com>, linux-omap@...r.kernel.org,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 9/9] omap mmc host: Use disable_irq_nosync() from within
 irq handlers.

Should I queue this up or do you want to do something differently for
this?

On Thu, 16 Apr 2009 15:55:21 +1000
Ben Nizette <bn@...sdigital.com> wrote:

> 
> disable_irq() should wait for all running handlers to complete
> before returning.  As such, if it's used to disable an interrupt
> from that interrupt's handler it will deadlock.  This replaces
> the dangerous instances with the _nosync() variant which doesn't
> have this problem.
> 
> Signed-off-by: Ben Nizette <bn@...sdigital.com>
> ---
> diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c
> index 5570849..d5ea652 100644
> --- a/drivers/mmc/host/omap.c
> +++ b/drivers/mmc/host/omap.c
> @@ -824,7 +824,7 @@ static irqreturn_t mmc_omap_irq(int irq, void *dev_id)
>  		del_timer(&host->cmd_abort_timer);
>  		host->abort = 1;
>  		OMAP_MMC_WRITE(host, IE, 0);
> -		disable_irq(host->irq);
> +		disable_irq_nosync(host->irq);
>  		schedule_work(&host->cmd_abort_work);
>  		return IRQ_HANDLED;
>  	}


-- 
     -- Pierre Ossman

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