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@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Luciano Coelho <coelho@xxxxxx>
> ---
> 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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