netdev - [patch 16/30] mfd: ab8500-debugfs: Remove the racy fiddling with irq

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Message-Id: <20201210194044.157283633@linutronix.de>
Date:   Thu, 10 Dec 2020 20:25:52 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Marc Zyngier <maz@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Lee Jones <lee.jones@...aro.org>,
        linux-arm-kernel@...ts.infradead.org,
        "James E.J. Bottomley" <James.Bottomley@...senPartnership.com>,
        Helge Deller <deller@....de>,
        afzal mohammed <afzal.mohd.ma@...il.com>,
        linux-parisc@...r.kernel.org, Russell King <linux@...linux.org.uk>,
        Mark Rutland <mark.rutland@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Heiko Carstens <hca@...ux.ibm.com>, linux-s390@...r.kernel.org,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@...el.com>,
        Chris Wilson <chris@...is-wilson.co.uk>,
        Wambui Karuga <wambui.karugax@...il.com>,
        intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>,
        linux-gpio@...r.kernel.org, Jon Mason <jdmason@...zu.us>,
        Dave Jiang <dave.jiang@...el.com>,
        Allen Hubbe <allenbh@...il.com>, linux-ntb@...glegroups.com,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
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        "David S. Miller" <davem@...emloft.net>,
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        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        xen-devel@...ts.xenproject.org
Subject: [patch 16/30] mfd: ab8500-debugfs: Remove the racy fiddling with irq_desc

First of all drivers have absolutely no business to dig into the internals
of an irq descriptor. That's core code and subject to change. All of this
information is readily available to /proc/interrupts in a safe and race
free way.

Remove the inspection code which is a blatant violation of subsystem
boundaries and racy against concurrent modifications of the interrupt
descriptor.

Print the irq line instead so the information can be looked up in a sane
way in /proc/interrupts.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Linus Walleij <linus.walleij@...aro.org>
Cc: Lee Jones <lee.jones@...aro.org>
Cc: linux-arm-kernel@...ts.infradead.org
---
 drivers/mfd/ab8500-debugfs.c |   16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

--- a/drivers/mfd/ab8500-debugfs.c
+++ b/drivers/mfd/ab8500-debugfs.c
@@ -1513,24 +1513,14 @@ static int ab8500_interrupts_show(struct
 {
 	int line;
 
-	seq_puts(s, "name: number:  number of: wake:\n");
+	seq_puts(s, "name: number: irq: number of: wake:\n");
 
 	for (line = 0; line < num_interrupt_lines; line++) {
-		struct irq_desc *desc = irq_to_desc(line + irq_first);
-
-		seq_printf(s, "%3i:  %6i %4i",
+		seq_printf(s, "%3i:  %6i %4i %4i\n",
 			   line,
+			   line + irq_first,
 			   num_interrupts[line],
 			   num_wake_interrupts[line]);
-
-		if (desc && desc->name)
-			seq_printf(s, "-%-8s", desc->name);
-		if (desc && desc->action) {
-			struct irqaction *action = desc->action;
-
-			seq_printf(s, "  %s", action->name);
-			while ((action = action->next) != NULL)
-				seq_printf(s, ", %s", action->name);
 		}
 		seq_putc(s, '\n');
 	}