[PATCH 6/6] userns: Use irqsave variant of refcount_dec_and_lock()

From: Sebastian Andrzej Siewior
Date: Tue Jul 03 2018 - 16:05:20 EST


From: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>

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.

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
[bigeasy: s@atomic_dec_and_lock@refcount_dec_and_lock@g ]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
kernel/user.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/kernel/user.c b/kernel/user.c
index 5f65ef195259..0df9b1640b2a 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 (refcount_dec_and_lock(&up->__count, &uidhash_lock))
+ if (refcount_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)
--
2.18.0