x86/paravirt: add spin_lock_flags lock op

It is useful for a pv_lock_ops backend to know whether interrupts are
enabled or not in the context a spin_lock is being called.  This
allows it to enable interrupts while spinning, which could be
particularly helpful when spinning becomes blocking.

The default implementation just calls the normal spin_lock op,
ignoring the flags.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/paravirt-spinlocks.c b/arch/x86/kernel/paravirt-spinlocks.c
index 38d7f7f1dbc9e3de0ea5246eb0b5c90c6d0e14bc..206359a8e43f3d37c1c1d372200812272bb45941 100644 (file)
--- a/arch/x86/kernel/paravirt-spinlocks.c
+++ b/arch/x86/kernel/paravirt-spinlocks.c
@@ -7,12 +7,18 @@
 
 #include <asm/paravirt.h>
 
+static void default_spin_lock_flags(struct raw_spinlock *lock, unsigned long flags)
+{
+       __raw_spin_lock(lock);
+}
+
 struct pv_lock_ops pv_lock_ops = {
 #ifdef CONFIG_SMP
        .spin_is_locked = __ticket_spin_is_locked,
        .spin_is_contended = __ticket_spin_is_contended,
 
        .spin_lock = __ticket_spin_lock,
+       .spin_lock_flags = default_spin_lock_flags,
        .spin_trylock = __ticket_spin_trylock,
        .spin_unlock = __ticket_spin_unlock,
 #endif

diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h
index db9b0647b346e87ce6eb9f31567ebe8017e47a57..8e9b1266898c1e7aaff682b1ea2ceca49c9de9c0 100644 (file)
--- a/include/asm-x86/paravirt.h
+++ b/include/asm-x86/paravirt.h
@@ -333,6 +333,7 @@ struct pv_lock_ops {
        int (*spin_is_locked)(struct raw_spinlock *lock);
        int (*spin_is_contended)(struct raw_spinlock *lock);
        void (*spin_lock)(struct raw_spinlock *lock);
+       void (*spin_lock_flags)(struct raw_spinlock *lock, unsigned long flags);
        int (*spin_trylock)(struct raw_spinlock *lock);
        void (*spin_unlock)(struct raw_spinlock *lock);
 };
@@ -1414,6 +1415,12 @@ static __always_inline void __raw_spin_lock(struct raw_spinlock *lock)
        PVOP_VCALL1(pv_lock_ops.spin_lock, lock);
 }
 
+static __always_inline void __raw_spin_lock_flags(struct raw_spinlock *lock,
+                                                 unsigned long flags)
+{
+       PVOP_VCALL2(pv_lock_ops.spin_lock_flags, lock, flags);
+}
+
 static __always_inline int __raw_spin_trylock(struct raw_spinlock *lock)
 {
        return PVOP_CALL1(int, pv_lock_ops.spin_trylock, lock);

diff --git a/include/asm-x86/spinlock.h b/include/asm-x86/spinlock.h
index e39c790dbfd2be789d812a6cdd89efc3d39cb5ec..b755ea86367e7e8187ba667821864089a4c89cdf 100644 (file)
--- a/include/asm-x86/spinlock.h
+++ b/include/asm-x86/spinlock.h
@@ -182,8 +182,6 @@ static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock)
 }
 #endif
 
-#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
-
 #ifdef CONFIG_PARAVIRT
 /*
  * Define virtualization-friendly old-style lock byte lock, for use in
@@ -272,6 +270,13 @@ static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
 {
        __ticket_spin_unlock(lock);
 }
+
+static __always_inline void __raw_spin_lock_flags(raw_spinlock_t *lock,
+                                                 unsigned long flags)
+{
+       __raw_spin_lock(lock);
+}
+
 #endif /* CONFIG_PARAVIRT */
 
 static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)