linux-kernel - [PATCH 3/5] kernel/user: Use irqsave variant of atomic_dec_and

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Date:   Fri,  4 May 2018 17:45:31 +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 3/5] kernel/user: 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>
---
 kernel/user.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/kernel/user.c b/kernel/user.c
index 36288d840675..8959ad11d766 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -169,11 +169,8 @@ void free_uid(struct user_struct *up)
 	if (!up)
 		return;
 
-	local_irq_save(flags);
-	if (atomic_dec_and_lock(&up->__count, &uidhash_lock))
+	if (atomic_dec_and_lock_irqsave(&up->__count, &uidhash_lock, flags))
 		free_user(up, flags);
-	else
-		local_irq_restore(flags);
 }
 
 struct user_struct *alloc_uid(kuid_t uid)
-- 
2.17.0