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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>
This commit is contained in:
Jeremy Fitzhardinge 2008-08-19 13:19:36 -07:00 committed by Ingo Molnar
parent 6e833587e1
commit 63d3a75d6f
3 changed files with 20 additions and 2 deletions
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6
arch/x86/kernel/paravirt-spinlocks.c
View File

@ -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

7
include/asm-x86/paravirt.h
View File

@ -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);

9
include/asm-x86/spinlock.h
View File

@ -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)