Re: [PATCH] wlcore: move handling from hardirq to the irq thread function

[Felipe Balbi <balbi@ti.com>]

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On Mon, Mar 25, 2013 at 12:53:44PM +0200, Luciano Coelho wrote:
> Spin locks and completions are expensive in hard IRQ context and cause
> problems with RT kernels.  In RT kernels, both spin locks and
> completions can schedule(), so we can't use them in hard irq context.
> 
> Move handling code into the irq thread function to avoid that.
> 
> Reported-by: Gregoire Gentil <gregoire@alwaysinnovating.com>
> Signed-off-by: Luciano Coelho <coelho@ti.com>
> ---
>  drivers/net/wireless/ti/wlcore/main.c |   53 +++++++++++++--------------------
>  1 file changed, 21 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/net/wireless/ti/wlcore/main.c b/drivers/net/wireless/ti/wlcore/main.c
> index 248daa9..c2730a7 100644
> --- a/drivers/net/wireless/ti/wlcore/main.c
> +++ b/drivers/net/wireless/ti/wlcore/main.c
> @@ -651,6 +651,25 @@ static irqreturn_t wlcore_irq(int irq, void *cookie)
>  	unsigned long flags;
>  	struct wl1271 *wl = cookie;
>  
> +	/* complete the ELP completion */
> +	spin_lock_irqsave(&wl->wl_lock, flags);
> +	set_bit(WL1271_FLAG_IRQ_RUNNING, &wl->flags);
> +	if (wl->elp_compl) {
> +		complete(wl->elp_compl);
> +		wl->elp_compl = NULL;
> +	}
> +
> +	if (test_bit(WL1271_FLAG_SUSPENDED, &wl->flags)) {
> +		/* don't enqueue a work right now. mark it as pending */
> +		set_bit(WL1271_FLAG_PENDING_WORK, &wl->flags);
> +		wl1271_debug(DEBUG_IRQ, "should not enqueue work");
> +		disable_irq_nosync(wl->irq);
> +		pm_wakeup_event(wl->dev, 0);
> +		spin_unlock_irqrestore(&wl->wl_lock, flags);
> +		return IRQ_HANDLED;
> +	}
> +	spin_unlock_irqrestore(&wl->wl_lock, flags);

I still think _irqrestore() here is wrong, since it will reenable the
IRQ line... other than that, it looks alright.

-- 
balbi

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