x86/paravirt: add spin_lock_flags lock op
Subsystems (2)
PATCH 1/1 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 <[email protected]>
--- arch/x86/kernel/paravirt-spinlocks.c | 6 ++++++ include/asm-x86/paravirt.h | 7 +++++++ include/asm-x86/spinlock.h | 9 +++++++-- 3 files changed, 20 insertions(+), 2 deletions(-)
===================================================================
arch/x86/kernel/paravirt-spinlocks.c +6 -0
@@ -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
===================================================================
include/asm-x86/paravirt.h +7 -0
@@ -328,6 +328,7 @@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); };
@@ -1396,6 +1397,12 @@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);
===================================================================
include/asm-x86/spinlock.h +7 -2
@@ -182,8 +182,6 @@ }#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 @@ {__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)