linux-kernel - [PATCH] percpu_counter: percpu_counter_hotcpu

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Message-ID: <1484922862.16328.117.camel@edumazet-glaptop3.roam.corp.google.com>
Date:   Fri, 20 Jan 2017 06:34:22 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-kernel <linux-kernel@...r.kernel.org>,
        Tejun Heo <tj@...nel.org>
Subject: [PATCH] percpu_counter: percpu_counter_hotcpu_callback() cleanup

From: Eric Dumazet <edumazet@...gle.com>

In commit ebd8fef304f9 ("percpu_counter: make percpu_counters_lock
irq-safe") we disabled irqs in percpu_counter_hotcpu_callback()

We can grab every counter spinlock without having to disable
irqs again.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Cc: Tejun Heo <tj@...nel.org>
---
 lib/percpu_counter.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index c8cebb1370765fac92170cd0d2f8ed1ede0a01da..9c21000df0b5ea1b99a83fd73a338073cb7fd016 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -176,13 +176,12 @@ static int percpu_counter_cpu_dead(unsigned int cpu)
 	spin_lock_irq(&percpu_counters_lock);
 	list_for_each_entry(fbc, &percpu_counters, list) {
 		s32 *pcount;
-		unsigned long flags;
 
-		raw_spin_lock_irqsave(&fbc->lock, flags);
+		raw_spin_lock(&fbc->lock);
 		pcount = per_cpu_ptr(fbc->counters, cpu);
 		fbc->count += *pcount;
 		*pcount = 0;
-		raw_spin_unlock_irqrestore(&fbc->lock, flags);
+		raw_spin_unlock(&fbc->lock);
 	}
 	spin_unlock_irq(&percpu_counters_lock);
 #endif