linux-kernel - Re: [patch 2/7] genirq/generic-chip: Convert core code to lock guards

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Message-ID: <CAMuHMdUkEpo4qPZe271H1=nBHRhKkKy5X70s9OSqxACxT3HJxw@mail.gmail.com>
Date: Tue, 8 Apr 2025 20:10:06 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>, Jiri Slaby <jirislaby@...nel.org>, 
	Andrew Lunn <andrew@...n.ch>, Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>, 
	Gregory Clement <gregory.clement@...tlin.com>, Uwe Kleine-König <ukleinek@...nel.org>, 
	Linus Walleij <linus.walleij@...aro.org>, Bartosz Golaszewski <brgl@...ev.pl>, 
	Talel Shenhar <talel@...zon.com>, Nicolas Ferre <nicolas.ferre@...rochip.com>, 
	Alexandre Belloni <alexandre.belloni@...tlin.com>, Claudiu Beznea <claudiu.beznea@...on.dev>, 
	Florian Fainelli <florian.fainelli@...adcom.com>, Guo Ren <guoren@...nel.org>, 
	Herve Codina <herve.codina@...tlin.com>, Huacai Chen <chenhuacai@...nel.org>, 
	Jiaxun Yang <jiaxun.yang@...goat.com>, Maxime Coquelin <mcoquelin.stm32@...il.com>, 
	Alexandre Torgue <alexandre.torgue@...s.st.com>, Chen-Yu Tsai <wens@...e.org>, 
	Jernej Skrabec <jernej.skrabec@...il.com>, Samuel Holland <samuel@...lland.org>
Subject: Re: [patch 2/7] genirq/generic-chip: Convert core code to lock guards

Hi Thomas,

On Thu, 13 Mar 2025 at 15:37, Thomas Gleixner <tglx@...utronix.de> wrote:
> Replace the irq_gc_lock/unlock() pairs with guards. There is no point to
> implement a guard wrapper for them as they just wrap around raw_spin_lock*().
>
> Switch the other lock instances in the core code to guards as well.
>
> Conversion was done with Coccinelle plus manual fixups.
>
> No functional change.
>
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>

Thanks for your patch, which is now commit 195298c3b11628a6
("genirq/generic-chip: Convert core code to lock guards") in
irqchip/irq/drivers.

> --- a/kernel/irq/generic-chip.c
> +++ b/kernel/irq/generic-chip.c
> @@ -340,9 +330,8 @@ int irq_domain_alloc_generic_chips(struc
>                                 goto err;
>                 }
>
> -               raw_spin_lock_irqsave(&gc_lock, flags);
> -               list_add_tail(&gc->list, &gc_list);
> -               raw_spin_unlock_irqrestore(&gc_lock, flags);
> +               scoped_guard (raw_spinlock, &gc_lock)
> +                       list_add_tail(&gc->list, &gc_list);
>                 /* Calc pointer to the next generic chip */
>                 tmp += gc_sz;
>         }
> @@ -459,7 +448,6 @@ int irq_map_generic_chip(struct irq_doma
>         struct irq_chip_generic *gc;
>         struct irq_chip_type *ct;
>         struct irq_chip *chip;
> -       unsigned long flags;
>         int idx;
>
>         gc = __irq_get_domain_generic_chip(d, hw_irq);
> @@ -479,9 +467,8 @@ int irq_map_generic_chip(struct irq_doma
>
>         /* We only init the cache for the first mapping of a generic chip */
>         if (!gc->installed) {
> -               raw_spin_lock_irqsave(&gc->lock, flags);
> +               guard(raw_spinlock_irq)(&gc->lock);
>                 irq_gc_init_mask_cache(gc, dgc->gc_flags);
> -               raw_spin_unlock_irqrestore(&gc->lock, flags);
>         }
>
>         /* Mark the interrupt as installed */

These two conversions are wrong. I have sent a patch:
https://lore.kernel.org/514f94c5891c61ac0a4a7fdad113e75db1eea367.1744135467.git.geert+renesas@glider.be

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds