From: Anna-Maria Gleixner <anna-maria@linutronix.de>
Date: Wed, 22 Aug 2018 04:55:35 +0000 (-0700)
Subject: bdi: use irqsave variant of refcount_dec_and_lock()
X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~4684^2~103
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=060288a7320b2837a8ff2af1b3643bdbd5e568f6;p=mirror_ubuntu-focal-kernel.git

bdi: use irqsave variant of refcount_dec_and_lock()

The irqsave variant of refcount_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.

[bigeasy@linutronix.de: s@atomic_dec_and_lock@refcount_dec_and_lock@g]
Link: http://lkml.kernel.org/r/20180703200141.28415-5-bigeasy@linutronix.de
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 55a233d75f39..f5981e9d6ae2 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -473,11 +473,8 @@ void wb_congested_put(struct bdi_writeback_congested *congested)
 {
 	unsigned long flags;
 
-	local_irq_save(flags);
-	if (!refcount_dec_and_lock(&congested->refcnt, &cgwb_lock)) {
-		local_irq_restore(flags);
+	if (!refcount_dec_and_lock_irqsave(&congested->refcnt, &cgwb_lock, &flags))
 		return;
-	}
 
 	/* bdi might already have been destroyed leaving @congested unlinked */
 	if (congested->__bdi) {