diff options
author | Waiman Long <longman@redhat.com> | 2019-04-04 13:43:11 -0400 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2019-04-10 10:55:59 +0200 |
commit | c7580c1e84435c9ccc6c612d9fee8e71811f7be6 (patch) | |
tree | f3ef56ac9ec00eeea7ebb6532604aee37a2cfca3 | |
parent | eecec78f777742903ec9167490c625661284155d (diff) | |
download | linux-c7580c1e84435c9ccc6c612d9fee8e71811f7be6.tar.gz linux-c7580c1e84435c9ccc6c612d9fee8e71811f7be6.tar.bz2 linux-c7580c1e84435c9ccc6c612d9fee8e71811f7be6.zip |
locking/rwsem: Move owner setting code from rwsem.c to rwsem.h
Move all the owner setting code closer to the rwsem-xadd fast paths
directly within rwsem.h file as well as in the slowpaths where owner
setting is done after acquring the lock. This will enable us to add
DEBUG_RWSEMS check in a later patch to make sure that read lock is
really acquired when rwsem_down_read_failed() returns, for instance.
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/20190404174320.22416-3-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r-- | kernel/locking/rwsem-xadd.c | 6 | ||||
-rw-r--r-- | kernel/locking/rwsem.c | 19 | ||||
-rw-r--r-- | kernel/locking/rwsem.h | 17 |
3 files changed, 20 insertions, 22 deletions
diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 0d518b52ade4..c213869e1aa7 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -176,9 +176,8 @@ static void __rwsem_mark_wake(struct rw_semaphore *sem, goto try_reader_grant; } /* - * It is not really necessary to set it to reader-owned here, - * but it gives the spinners an early indication that the - * readers now have the lock. + * Set it to reader-owned to give spinners an early + * indication that readers now have the lock. */ __rwsem_set_reader_owned(sem, waiter->task); } @@ -441,6 +440,7 @@ __rwsem_down_read_failed_common(struct rw_semaphore *sem, int state) */ if (atomic_long_read(&sem->count) >= 0) { raw_spin_unlock_irq(&sem->wait_lock); + rwsem_set_reader_owned(sem); return sem; } adjustment += RWSEM_WAITING_BIAS; diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index e586f0d03ad3..59e584895532 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -24,7 +24,6 @@ void __sched down_read(struct rw_semaphore *sem) rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_); LOCK_CONTENDED(sem, __down_read_trylock, __down_read); - rwsem_set_reader_owned(sem); } EXPORT_SYMBOL(down_read); @@ -39,7 +38,6 @@ int __sched down_read_killable(struct rw_semaphore *sem) return -EINTR; } - rwsem_set_reader_owned(sem); return 0; } @@ -52,10 +50,8 @@ int down_read_trylock(struct rw_semaphore *sem) { int ret = __down_read_trylock(sem); - if (ret == 1) { + if (ret == 1) rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_); - rwsem_set_reader_owned(sem); - } return ret; } @@ -70,7 +66,6 @@ void __sched down_write(struct rw_semaphore *sem) rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_); LOCK_CONTENDED(sem, __down_write_trylock, __down_write); - rwsem_set_owner(sem); } EXPORT_SYMBOL(down_write); @@ -88,7 +83,6 @@ int __sched down_write_killable(struct rw_semaphore *sem) return -EINTR; } - rwsem_set_owner(sem); return 0; } @@ -101,10 +95,8 @@ int down_write_trylock(struct rw_semaphore *sem) { int ret = __down_write_trylock(sem); - if (ret == 1) { + if (ret == 1) rwsem_acquire(&sem->dep_map, 0, 1, _RET_IP_); - rwsem_set_owner(sem); - } return ret; } @@ -119,7 +111,6 @@ void up_read(struct rw_semaphore *sem) rwsem_release(&sem->dep_map, 1, _RET_IP_); DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner & RWSEM_READER_OWNED)); - rwsem_clear_reader_owned(sem); __up_read(sem); } @@ -133,7 +124,6 @@ void up_write(struct rw_semaphore *sem) rwsem_release(&sem->dep_map, 1, _RET_IP_); DEBUG_RWSEMS_WARN_ON(sem->owner != current); - rwsem_clear_owner(sem); __up_write(sem); } @@ -147,7 +137,6 @@ void downgrade_write(struct rw_semaphore *sem) lock_downgrade(&sem->dep_map, _RET_IP_); DEBUG_RWSEMS_WARN_ON(sem->owner != current); - rwsem_set_reader_owned(sem); __downgrade_write(sem); } @@ -161,7 +150,6 @@ void down_read_nested(struct rw_semaphore *sem, int subclass) rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_); LOCK_CONTENDED(sem, __down_read_trylock, __down_read); - rwsem_set_reader_owned(sem); } EXPORT_SYMBOL(down_read_nested); @@ -172,7 +160,6 @@ void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest) rwsem_acquire_nest(&sem->dep_map, 0, 0, nest, _RET_IP_); LOCK_CONTENDED(sem, __down_write_trylock, __down_write); - rwsem_set_owner(sem); } EXPORT_SYMBOL(_down_write_nest_lock); @@ -193,7 +180,6 @@ void down_write_nested(struct rw_semaphore *sem, int subclass) rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_); LOCK_CONTENDED(sem, __down_write_trylock, __down_write); - rwsem_set_owner(sem); } EXPORT_SYMBOL(down_write_nested); @@ -208,7 +194,6 @@ int __sched down_write_killable_nested(struct rw_semaphore *sem, int subclass) return -EINTR; } - rwsem_set_owner(sem); return 0; } diff --git a/kernel/locking/rwsem.h b/kernel/locking/rwsem.h index 1f5775aa6a1d..ee24c4f257a5 100644 --- a/kernel/locking/rwsem.h +++ b/kernel/locking/rwsem.h @@ -160,6 +160,8 @@ static inline void __down_read(struct rw_semaphore *sem) { if (unlikely(atomic_long_inc_return_acquire(&sem->count) <= 0)) rwsem_down_read_failed(sem); + else + rwsem_set_reader_owned(sem); } static inline int __down_read_killable(struct rw_semaphore *sem) @@ -167,8 +169,9 @@ 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; + } else { + rwsem_set_reader_owned(sem); } - return 0; } @@ -182,6 +185,7 @@ static inline int __down_read_trylock(struct rw_semaphore *sem) do { if (atomic_long_try_cmpxchg_acquire(&sem->count, &tmp, tmp + RWSEM_ACTIVE_READ_BIAS)) { + rwsem_set_reader_owned(sem); return 1; } } while (tmp >= 0); @@ -199,6 +203,7 @@ static inline void __down_write(struct rw_semaphore *sem) &sem->count); if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS)) rwsem_down_write_failed(sem); + rwsem_set_owner(sem); } static inline int __down_write_killable(struct rw_semaphore *sem) @@ -210,6 +215,7 @@ static inline int __down_write_killable(struct rw_semaphore *sem) if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS)) if (IS_ERR(rwsem_down_write_failed_killable(sem))) return -EINTR; + rwsem_set_owner(sem); return 0; } @@ -219,7 +225,11 @@ static inline int __down_write_trylock(struct rw_semaphore *sem) tmp = atomic_long_cmpxchg_acquire(&sem->count, RWSEM_UNLOCKED_VALUE, RWSEM_ACTIVE_WRITE_BIAS); - return tmp == RWSEM_UNLOCKED_VALUE; + if (tmp == RWSEM_UNLOCKED_VALUE) { + rwsem_set_owner(sem); + return true; + } + return false; } /* @@ -229,6 +239,7 @@ static inline void __up_read(struct rw_semaphore *sem) { long tmp; + rwsem_clear_reader_owned(sem); tmp = atomic_long_dec_return_release(&sem->count); if (unlikely(tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0)) rwsem_wake(sem); @@ -239,6 +250,7 @@ static inline void __up_read(struct rw_semaphore *sem) */ static inline void __up_write(struct rw_semaphore *sem) { + rwsem_clear_owner(sem); if (unlikely(atomic_long_sub_return_release(RWSEM_ACTIVE_WRITE_BIAS, &sem->count) < 0)) rwsem_wake(sem); @@ -259,6 +271,7 @@ static inline void __downgrade_write(struct rw_semaphore *sem) * write side. As such, rely on RELEASE semantics. */ tmp = atomic_long_add_return_release(-RWSEM_WAITING_BIAS, &sem->count); + rwsem_set_reader_owned(sem); if (tmp < 0) rwsem_downgrade_wake(sem); } |