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>

2 files changed, 14 insertions, 2 deletions

diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h
index db9b0647b346..8e9b1266898c 100644
--- 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 e39c790dbfd2..b755ea86367e 100644
--- 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)