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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-06 13:50:15 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-06 13:50:15 -0700 |
commit | 007dc78fea62610bf06829e38f1d8c69b6ea5af6 (patch) | |
tree | 683af90696ed7a237dedd48030bfd649e5822955 /include/asm-generic | |
parent | 2f1835dffa949f560dfa3ed63c0bfc10944b461c (diff) | |
parent | d671002be6bdd7f77a771e23bf3e95d1f16775e6 (diff) | |
download | linux-007dc78fea62610bf06829e38f1d8c69b6ea5af6.tar.bz2 |
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"Here are the locking changes in this cycle:
- rwsem unification and simpler micro-optimizations to prepare for
more intrusive (and more lucrative) scalability improvements in
v5.3 (Waiman Long)
- Lockdep irq state tracking flag usage cleanups (Frederic
Weisbecker)
- static key improvements (Jakub Kicinski, Peter Zijlstra)
- misc updates, cleanups and smaller fixes"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
locking/lockdep: Remove unnecessary unlikely()
locking/static_key: Don't take sleeping locks in __static_key_slow_dec_deferred()
locking/static_key: Factor out the fast path of static_key_slow_dec()
locking/static_key: Add support for deferred static branches
locking/lockdep: Test all incompatible scenarios at once in check_irq_usage()
locking/lockdep: Avoid bogus Clang warning
locking/lockdep: Generate LOCKF_ bit composites
locking/lockdep: Use expanded masks on find_usage_*() functions
locking/lockdep: Map remaining magic numbers to lock usage mask names
locking/lockdep: Move valid_state() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING
locking/rwsem: Prevent unneeded warning during locking selftest
locking/rwsem: Optimize rwsem structure for uncontended lock acquisition
locking/rwsem: Enable lock event counting
locking/lock_events: Don't show pvqspinlock events on bare metal
locking/lock_events: Make lock_events available for all archs & other locks
locking/qspinlock_stat: Introduce generic lockevent_*() counting APIs
locking/rwsem: Enhance DEBUG_RWSEMS_WARN_ON() macro
locking/rwsem: Add debug check for __down_read*()
locking/rwsem: Micro-optimize rwsem_try_read_lock_unqueued()
locking/rwsem: Move rwsem internal function declarations to rwsem-xadd.h
...
Diffstat (limited to 'include/asm-generic')
-rw-r--r-- | include/asm-generic/rwsem.h | 140 |
1 files changed, 0 insertions, 140 deletions
diff --git a/include/asm-generic/rwsem.h b/include/asm-generic/rwsem.h deleted file mode 100644 index 93e67a055a4d..000000000000 --- a/include/asm-generic/rwsem.h +++ /dev/null @@ -1,140 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _ASM_GENERIC_RWSEM_H -#define _ASM_GENERIC_RWSEM_H - -#ifndef _LINUX_RWSEM_H -#error "Please don't include <asm/rwsem.h> directly, use <linux/rwsem.h> instead." -#endif - -#ifdef __KERNEL__ - -/* - * R/W semaphores originally for PPC using the stuff in lib/rwsem.c. - * Adapted largely from include/asm-i386/rwsem.h - * by Paul Mackerras <paulus@samba.org>. - */ - -/* - * the semaphore definition - */ -#ifdef CONFIG_64BIT -# define RWSEM_ACTIVE_MASK 0xffffffffL -#else -# define RWSEM_ACTIVE_MASK 0x0000ffffL -#endif - -#define RWSEM_UNLOCKED_VALUE 0x00000000L -#define RWSEM_ACTIVE_BIAS 0x00000001L -#define RWSEM_WAITING_BIAS (-RWSEM_ACTIVE_MASK-1) -#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) - -/* - * lock for reading - */ -static inline void __down_read(struct rw_semaphore *sem) -{ - if (unlikely(atomic_long_inc_return_acquire(&sem->count) <= 0)) - rwsem_down_read_failed(sem); -} - -static inline int __down_read_killable(struct rw_semaphore *sem) -{ - if (unlikely(atomic_long_inc_return_acquire(&sem->count) <= 0)) { - if (IS_ERR(rwsem_down_read_failed_killable(sem))) - return -EINTR; - } - - return 0; -} - -static inline int __down_read_trylock(struct rw_semaphore *sem) -{ - long tmp; - - while ((tmp = atomic_long_read(&sem->count)) >= 0) { - if (tmp == atomic_long_cmpxchg_acquire(&sem->count, tmp, - tmp + RWSEM_ACTIVE_READ_BIAS)) { - return 1; - } - } - return 0; -} - -/* - * lock for writing - */ -static inline void __down_write(struct rw_semaphore *sem) -{ - long tmp; - - tmp = atomic_long_add_return_acquire(RWSEM_ACTIVE_WRITE_BIAS, - &sem->count); - if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS)) - rwsem_down_write_failed(sem); -} - -static inline int __down_write_killable(struct rw_semaphore *sem) -{ - long tmp; - - tmp = atomic_long_add_return_acquire(RWSEM_ACTIVE_WRITE_BIAS, - &sem->count); - if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS)) - if (IS_ERR(rwsem_down_write_failed_killable(sem))) - return -EINTR; - return 0; -} - -static inline int __down_write_trylock(struct rw_semaphore *sem) -{ - long tmp; - - tmp = atomic_long_cmpxchg_acquire(&sem->count, RWSEM_UNLOCKED_VALUE, - RWSEM_ACTIVE_WRITE_BIAS); - return tmp == RWSEM_UNLOCKED_VALUE; -} - -/* - * unlock after reading - */ -static inline void __up_read(struct rw_semaphore *sem) -{ - long tmp; - - tmp = atomic_long_dec_return_release(&sem->count); - if (unlikely(tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0)) - rwsem_wake(sem); -} - -/* - * unlock after writing - */ -static inline void __up_write(struct rw_semaphore *sem) -{ - if (unlikely(atomic_long_sub_return_release(RWSEM_ACTIVE_WRITE_BIAS, - &sem->count) < 0)) - rwsem_wake(sem); -} - -/* - * downgrade write lock to read lock - */ -static inline void __downgrade_write(struct rw_semaphore *sem) -{ - long tmp; - - /* - * When downgrading from exclusive to shared ownership, - * anything inside the write-locked region cannot leak - * into the read side. In contrast, anything in the - * read-locked region is ok to be re-ordered into the - * write side. As such, rely on RELEASE semantics. - */ - tmp = atomic_long_add_return_release(-RWSEM_WAITING_BIAS, &sem->count); - if (tmp < 0) - rwsem_downgrade_wake(sem); -} - -#endif /* __KERNEL__ */ -#endif /* _ASM_GENERIC_RWSEM_H */ |