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

-----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.c...

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;