diff options
Diffstat (limited to 'include/linux/spinlock.h')
| -rw-r--r-- | include/linux/spinlock.h | 51 |
1 files changed, 35 insertions, 16 deletions
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index 86088213334..3f2867ff0ce 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -50,17 +50,18 @@ #include <linux/preempt.h> #include <linux/linkage.h> #include <linux/compiler.h> +#include <linux/irqflags.h> #include <linux/thread_info.h> #include <linux/kernel.h> #include <linux/stringify.h> #include <linux/bottom_half.h> +#include <asm/barrier.h> -#include <asm/system.h> /* * Must define these before including other files, inline functions need them */ -#define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME +#define LOCK_SECTION_NAME ".text..lock."KBUILD_BASENAME #define LOCK_SECTION_START(extra) \ ".subsection 1\n\t" \ @@ -80,7 +81,7 @@ #include <linux/spinlock_types.h> /* - * Pull the arch_spin*() functions/declarations (UP-nondebug doesnt need them): + * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't need them): */ #ifdef CONFIG_SMP # include <asm/spinlock.h> @@ -116,9 +117,27 @@ do { \ #endif /*arch_spin_is_contended*/ #endif -/* The lock does not imply full memory barrier. */ -#ifndef ARCH_HAS_SMP_MB_AFTER_LOCK -static inline void smp_mb__after_lock(void) { smp_mb(); } +/* + * Despite its name it doesn't necessarily has to be a full barrier. + * It should only guarantee that a STORE before the critical section + * can not be reordered with a LOAD inside this section. + * spin_lock() is the one-way barrier, this LOAD can not escape out + * of the region. So the default implementation simply ensures that + * a STORE can not move into the critical section, smp_wmb() should + * serialize it with another STORE done by spin_lock(). + */ +#ifndef smp_mb__before_spinlock +#define smp_mb__before_spinlock() smp_wmb() +#endif + +/* + * Place this after a lock-acquisition primitive to guarantee that + * an UNLOCK+LOCK pair act as a full barrier. This guarantee applies + * if the UNLOCK and LOCK are executed by the same CPU or if the + * UNLOCK and LOCK operate on the same lock variable. + */ +#ifndef smp_mb__after_unlock_lock +#define smp_mb__after_unlock_lock() do { } while (0) #endif /** @@ -128,19 +147,21 @@ static inline void smp_mb__after_lock(void) { smp_mb(); } #define raw_spin_unlock_wait(lock) arch_spin_unlock_wait(&(lock)->raw_lock) #ifdef CONFIG_DEBUG_SPINLOCK - extern void do_raw_spin_lock(raw_spinlock_t *lock); + extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock); #define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock) extern int do_raw_spin_trylock(raw_spinlock_t *lock); - extern void do_raw_spin_unlock(raw_spinlock_t *lock); + extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock); #else -static inline void do_raw_spin_lock(raw_spinlock_t *lock) +static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock) { + __acquire(lock); arch_spin_lock(&lock->raw_lock); } static inline void -do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) +do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock) { + __acquire(lock); arch_spin_lock_flags(&lock->raw_lock, *flags); } @@ -149,9 +170,10 @@ static inline int do_raw_spin_trylock(raw_spinlock_t *lock) return arch_spin_trylock(&(lock)->raw_lock); } -static inline void do_raw_spin_unlock(raw_spinlock_t *lock) +static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock) { arch_spin_unlock(&lock->raw_lock); + __release(lock); } #endif @@ -371,16 +393,13 @@ static inline int spin_can_lock(spinlock_t *lock) return raw_spin_can_lock(&lock->rlock); } -static inline void assert_spin_locked(spinlock_t *lock) -{ - assert_raw_spin_locked(&lock->rlock); -} +#define assert_spin_locked(lock) assert_raw_spin_locked(&(lock)->rlock) /* * Pull the atomic_t declaration: * (asm-mips/atomic.h needs above definitions) */ -#include <asm/atomic.h> +#include <linux/atomic.h> /** * atomic_dec_and_lock - lock on reaching reference count zero * @atomic: the atomic counter |