From 1751060e2527462714359573a39dca10451ffbf8 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 30 Oct 2019 20:01:26 +0100 Subject: locking/percpu-rwsem, lockdep: Make percpu-rwsem use its own lockdep_map As preparation for replacing the embedded rwsem, give percpu-rwsem its own lockdep_map. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Davidlohr Bueso Acked-by: Will Deacon Acked-by: Waiman Long Tested-by: Juri Lelli Link: https://lkml.kernel.org/r/20200131151539.927625541@infradead.org --- include/linux/percpu-rwsem.h | 29 +++++++++++++++++++---------- kernel/cpu.c | 4 ++-- kernel/locking/percpu-rwsem.c | 16 ++++++++++++---- kernel/locking/rwsem.c | 4 ++-- kernel/locking/rwsem.h | 2 ++ 5 files changed, 37 insertions(+), 18 deletions(-) diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h index ad2ca2a89d5b..f2c36fb5e661 100644 --- a/include/linux/percpu-rwsem.h +++ b/include/linux/percpu-rwsem.h @@ -15,8 +15,17 @@ struct percpu_rw_semaphore { struct rw_semaphore rw_sem; /* slowpath */ struct rcuwait writer; /* blocked writer */ int readers_block; +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map dep_map; +#endif }; +#ifdef CONFIG_DEBUG_LOCK_ALLOC +#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname) .dep_map = { .name = #lockname }, +#else +#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname) +#endif + #define __DEFINE_PERCPU_RWSEM(name, is_static) \ static DEFINE_PER_CPU(unsigned int, __percpu_rwsem_rc_##name); \ is_static struct percpu_rw_semaphore name = { \ @@ -24,7 +33,9 @@ is_static struct percpu_rw_semaphore name = { \ .read_count = &__percpu_rwsem_rc_##name, \ .rw_sem = __RWSEM_INITIALIZER(name.rw_sem), \ .writer = __RCUWAIT_INITIALIZER(name.writer), \ + __PERCPU_RWSEM_DEP_MAP_INIT(name) \ } + #define DEFINE_PERCPU_RWSEM(name) \ __DEFINE_PERCPU_RWSEM(name, /* not static */) #define DEFINE_STATIC_PERCPU_RWSEM(name) \ @@ -37,7 +48,7 @@ static inline void percpu_down_read(struct percpu_rw_semaphore *sem) { might_sleep(); - rwsem_acquire_read(&sem->rw_sem.dep_map, 0, 0, _RET_IP_); + rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_); preempt_disable(); /* @@ -76,13 +87,15 @@ static inline int percpu_down_read_trylock(struct percpu_rw_semaphore *sem) */ if (ret) - rwsem_acquire_read(&sem->rw_sem.dep_map, 0, 1, _RET_IP_); + rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_); return ret; } static inline void percpu_up_read(struct percpu_rw_semaphore *sem) { + rwsem_release(&sem->dep_map, _RET_IP_); + preempt_disable(); /* * Same as in percpu_down_read(). @@ -92,8 +105,6 @@ static inline void percpu_up_read(struct percpu_rw_semaphore *sem) else __percpu_up_read(sem); /* Unconditional memory barrier */ preempt_enable(); - - rwsem_release(&sem->rw_sem.dep_map, _RET_IP_); } extern void percpu_down_write(struct percpu_rw_semaphore *); @@ -110,15 +121,13 @@ extern void percpu_free_rwsem(struct percpu_rw_semaphore *); __percpu_init_rwsem(sem, #sem, &rwsem_key); \ }) -#define percpu_rwsem_is_held(sem) lockdep_is_held(&(sem)->rw_sem) - -#define percpu_rwsem_assert_held(sem) \ - lockdep_assert_held(&(sem)->rw_sem) +#define percpu_rwsem_is_held(sem) lockdep_is_held(sem) +#define percpu_rwsem_assert_held(sem) lockdep_assert_held(sem) static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem, bool read, unsigned long ip) { - lock_release(&sem->rw_sem.dep_map, ip); + lock_release(&sem->dep_map, ip); #ifdef CONFIG_RWSEM_SPIN_ON_OWNER if (!read) atomic_long_set(&sem->rw_sem.owner, RWSEM_OWNER_UNKNOWN); @@ -128,7 +137,7 @@ static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem, static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem, bool read, unsigned long ip) { - lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip); + lock_acquire(&sem->dep_map, 0, 1, read, 1, NULL, ip); #ifdef CONFIG_RWSEM_SPIN_ON_OWNER if (!read) atomic_long_set(&sem->rw_sem.owner, (long)current); diff --git a/kernel/cpu.c b/kernel/cpu.c index 9c706af713fb..221bf6a9e98a 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -331,12 +331,12 @@ void lockdep_assert_cpus_held(void) static void lockdep_acquire_cpus_lock(void) { - rwsem_acquire(&cpu_hotplug_lock.rw_sem.dep_map, 0, 0, _THIS_IP_); + rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_); } static void lockdep_release_cpus_lock(void) { - rwsem_release(&cpu_hotplug_lock.rw_sem.dep_map, _THIS_IP_); + rwsem_release(&cpu_hotplug_lock.dep_map, _THIS_IP_); } /* diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c index 364d38a0c444..aa2b118d2f88 100644 --- a/kernel/locking/percpu-rwsem.c +++ b/kernel/locking/percpu-rwsem.c @@ -11,7 +11,7 @@ #include "rwsem.h" int __percpu_init_rwsem(struct percpu_rw_semaphore *sem, - const char *name, struct lock_class_key *rwsem_key) + const char *name, struct lock_class_key *key) { sem->read_count = alloc_percpu(int); if (unlikely(!sem->read_count)) @@ -19,9 +19,13 @@ int __percpu_init_rwsem(struct percpu_rw_semaphore *sem, /* ->rw_sem represents the whole percpu_rw_semaphore for lockdep */ rcu_sync_init(&sem->rss); - __init_rwsem(&sem->rw_sem, name, rwsem_key); + init_rwsem(&sem->rw_sem); rcuwait_init(&sem->writer); sem->readers_block = 0; +#ifdef CONFIG_DEBUG_LOCK_ALLOC + debug_check_no_locks_freed((void *)sem, sizeof(*sem)); + lockdep_init_map(&sem->dep_map, name, key, 0); +#endif return 0; } EXPORT_SYMBOL_GPL(__percpu_init_rwsem); @@ -142,10 +146,12 @@ static bool readers_active_check(struct percpu_rw_semaphore *sem) void percpu_down_write(struct percpu_rw_semaphore *sem) { + rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_); + /* Notify readers to take the slow path. */ rcu_sync_enter(&sem->rss); - down_write(&sem->rw_sem); + __down_write(&sem->rw_sem); /* * Notify new readers to block; up until now, and thus throughout the @@ -168,6 +174,8 @@ EXPORT_SYMBOL_GPL(percpu_down_write); void percpu_up_write(struct percpu_rw_semaphore *sem) { + rwsem_release(&sem->dep_map, _RET_IP_); + /* * Signal the writer is done, no fast path yet. * @@ -183,7 +191,7 @@ void percpu_up_write(struct percpu_rw_semaphore *sem) /* * Release the write lock, this will allow readers back in the game. */ - up_write(&sem->rw_sem); + __up_write(&sem->rw_sem); /* * Once this completes (at least one RCU-sched grace period hence) the diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 0d9b6be9ecc8..30df8dff217b 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -1383,7 +1383,7 @@ static inline int __down_read_trylock(struct rw_semaphore *sem) /* * lock for writing */ -static inline void __down_write(struct rw_semaphore *sem) +inline void __down_write(struct rw_semaphore *sem) { long tmp = RWSEM_UNLOCKED_VALUE; @@ -1446,7 +1446,7 @@ inline void __up_read(struct rw_semaphore *sem) /* * unlock after writing */ -static inline void __up_write(struct rw_semaphore *sem) +inline void __up_write(struct rw_semaphore *sem) { long tmp; diff --git a/kernel/locking/rwsem.h b/kernel/locking/rwsem.h index 2534ce49f648..d0d33a59622d 100644 --- a/kernel/locking/rwsem.h +++ b/kernel/locking/rwsem.h @@ -6,5 +6,7 @@ extern void __down_read(struct rw_semaphore *sem); extern void __up_read(struct rw_semaphore *sem); +extern void __down_write(struct rw_semaphore *sem); +extern void __up_write(struct rw_semaphore *sem); #endif /* __INTERNAL_RWSEM_H */ -- cgit