RE: [PATCH v3 01/12] genirq: add IRQF_NO_AUTOEN for request_irq

Song Bao Hua (Barry Song)
2021-02-01T04:09:52Z

> -----Original Message-----
> From: Thomas Gleixner [mailto:tglx@linutronix.de]
> Sent: Friday, January 29, 2021 8:55 AM
> To: Song Bao Hua (Barry Song) <song.bao.hua@hisilicon.com>;
> dmitry.torokhov@gmail.com; maz@kernel.org; gregkh@linuxfoundation.org;
> linux-input@vger.kernel.org; linux-kernel@vger.kernel.org
> Cc: linuxarm@openeuler.org; Song Bao Hua (Barry Song)
> <song.bao.hua@hisilicon.com>
> Subject: Re: [PATCH v3 01/12] genirq: add IRQF_NO_AUTOEN for request_irq
>
> Barry,
>
> On Fri, Jan 08 2021 at 11:39, Barry Song wrote:
> > diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> > index ab8567f32501..2b28314e2572 100644
> > --- a/kernel/irq/manage.c
> > +++ b/kernel/irq/manage.c
> > @@ -1693,6 +1693,9 @@ __setup_irq(unsigned int irq, struct irq_desc *desc,
> struct irqaction *new)
> > irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
> > }
> >
> > + if (new->flags & IRQF_NO_AUTOEN)
> > + irq_settings_set_noautoen(desc);
>
> If we move this to request time flags, then setting the noautoen bit on
> the irq descriptor is pretty pointless. See below.
>
> I rather get rid of the irq_settings magic for NOAUTOEN completely.

Thanks for your comment, Thomas.

Got this issue fixed in v4:
https://lore.kernel.org/lkml/20210128223538.20272-1-song.bao.hua@hisilicon.com/

btw, for those drivers which are using the first pattern:
irq_set_status_flags(irq, IRQ_NOAUTOEN);
request_irq(dev, irq...);

Simply running "git grep IRQ_NOAUTOEN" will help figure where to fix.

For those drivers which are using the second pattern:
request_irq(dev, irq...);
disable_irq(irq);

I wrote a script as below:

#!/bin/bash
if [ $# != 1 -o ! -d $1 ] ; then
echo "USAGE: $0 dir"
exit 1;
fi

find $1 -iname "*.c" | while read i
do
if [ -d "$i" ]; then
break
fi

irq=`grep -n -A 10 -E "request_irq|request_threaded_irq|request_any_context_irq" $i | grep disable_irq`
if [ "$irq" != "" ]; then
echo "$i":"$irq"
fi
done

The script says there are more than 70 cases in 5.11-rc6.
We are going to fix all of them after this one settles down.

Thanks
Barry

>
> Thanks,
>
> tglx
> ---
> --- a/include/linux/interrupt.h
> +++ b/include/linux/interrupt.h
> @@ -61,6 +61,8 @@
> * interrupt handler after suspending interrupts. For system
> * wakeup devices users need to implement wakeup detection in
> * their interrupt handlers.
> + * IRQF_NO_AUTOEN - Don't enable IRQ automatically when users request it. Users
> + * will enable it explicitly by enable_irq() later.
> */
> #define IRQF_SHARED 0x00000080
> #define IRQF_PROBE_SHARED 0x00000100
> @@ -74,6 +76,7 @@
> #define IRQF_NO_THREAD 0x00010000
> #define IRQF_EARLY_RESUME 0x00020000
> #define IRQF_COND_SUSPEND 0x00040000
> +#define IRQF_NO_AUTOEN 0x00080000
>
> #define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
>
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -1693,7 +1693,8 @@ static int
> irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
> }
>
> - if (irq_settings_can_autoenable(desc)) {
> + if (!(new->flags & IRQF_NO_AUTOEN) &&
> + irq_settings_can_autoenable(desc)) {
> irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
> } else {
> /*
> @@ -2086,10 +2087,15 @@ int request_threaded_irq(unsigned int ir
> * which interrupt is which (messes up the interrupt freeing
> * logic etc).
> *
> + * Also shared interrupts do not go well with disabling auto enable.
> + * The sharing interrupt might request it while it's still disabled
> + * and then wait for interrupts forever.
> + *
> * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
> * it cannot be set along with IRQF_NO_SUSPEND.
> */
> if (((irqflags & IRQF_SHARED) && !dev_id) ||
> + ((irqflags & IRQF_SHARED) && (irqflags & IRQF_NO_AUTOEN)) ||
> (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
> ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
> return -EINVAL;