linux-kernel - [PATCH 2/5] mm/backing-dev: Use irqsave variant of atomic_dec_and

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Date:   Fri,  4 May 2018 17:45:30 +0200
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     linux-kernel@...r.kernel.org
Cc:     tglx@...utronix.de, Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>, linux-mm@...ck.org,
        Shaohua Li <shli@...nel.org>, linux-raid@...r.kernel.org,
        Anna-Maria Gleixner <anna-maria@...utronix.de>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH 2/5] mm/backing-dev: Use irqsave variant of atomic_dec_and_lock()

From: Anna-Maria Gleixner <anna-maria@...utronix.de>

The irqsave variant of atomic_dec_and_lock handles irqsave/restore when
taking/releasing the spin lock. With this variant the call of
local_irq_save/restore is no longer required.

Signed-off-by: Anna-Maria Gleixner <anna-maria@...utronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 mm/backing-dev.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 023190c69dce..c28418914591 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -484,11 +484,8 @@ void wb_congested_put(struct bdi_writeback_congested *congested)
 {
 	unsigned long flags;
 
-	local_irq_save(flags);
-	if (!atomic_dec_and_lock(&congested->refcnt, &cgwb_lock)) {
-		local_irq_restore(flags);
+	if (!atomic_dec_and_lock_irqsave(&congested->refcnt, &cgwb_lock, flags))
 		return;
-	}
 
 	/* bdi might already have been destroyed leaving @congested unlinked */
 	if (congested->__bdi) {
-- 
2.17.0