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authorWill Deacon <will.deacon@arm.com>2018-04-26 13:34:24 +0300
committerIngo Molnar <mingo@kernel.org>2018-04-27 10:48:51 +0300
commit626e5fbc14358901ddaa90ce510e0fbeab310432 (patch)
treea6cb035242e8be6594881d19068fdeeaae6b24dc /arch/x86/include/asm/qspinlock.h
parentc131a198c497db436b558ac5e9a140cdcb91b304 (diff)
downloadlinux-626e5fbc14358901ddaa90ce510e0fbeab310432.tar.xz
locking/qspinlock: Use smp_store_release() in queued_spin_unlock()
A qspinlock can be unlocked simply by writing zero to the locked byte. This can be implemented in the generic code, so do that and remove the arch-specific override for x86 in the !PV case. Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Waiman Long <longman@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: boqun.feng@gmail.com Cc: linux-arm-kernel@lists.infradead.org Cc: paulmck@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/1524738868-31318-11-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/qspinlock.h')
-rw-r--r--arch/x86/include/asm/qspinlock.h17
1 files changed, 6 insertions, 11 deletions
diff --git a/arch/x86/include/asm/qspinlock.h b/arch/x86/include/asm/qspinlock.h
index da1370ad206d..3e70bed8a978 100644
--- a/arch/x86/include/asm/qspinlock.h
+++ b/arch/x86/include/asm/qspinlock.h
@@ -9,6 +9,12 @@
#define _Q_PENDING_LOOPS (1 << 9)
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+extern void native_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
+extern void __pv_init_lock_hash(void);
+extern void __pv_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
+extern void __raw_callee_save___pv_queued_spin_unlock(struct qspinlock *lock);
+
#define queued_spin_unlock queued_spin_unlock
/**
* queued_spin_unlock - release a queued spinlock
@@ -21,12 +27,6 @@ static inline void native_queued_spin_unlock(struct qspinlock *lock)
smp_store_release(&lock->locked, 0);
}
-#ifdef CONFIG_PARAVIRT_SPINLOCKS
-extern void native_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
-extern void __pv_init_lock_hash(void);
-extern void __pv_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
-extern void __raw_callee_save___pv_queued_spin_unlock(struct qspinlock *lock);
-
static inline void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
{
pv_queued_spin_lock_slowpath(lock, val);
@@ -42,11 +42,6 @@ static inline bool vcpu_is_preempted(long cpu)
{
return pv_vcpu_is_preempted(cpu);
}
-#else
-static inline void queued_spin_unlock(struct qspinlock *lock)
-{
- native_queued_spin_unlock(lock);
-}
#endif
#ifdef CONFIG_PARAVIRT