From: Thomas Gleixner Date: Wed, 24 Feb 2010 08:54:54 +0000 (+0100) Subject: locking, rwsem: Annotate inner lock as raw X-Git-Tag: firefly_0821_release~3680^2~4310^2~17 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ddb6c9b58a19edcfac93ac670b066c836ff729f1;p=firefly-linux-kernel-4.4.55.git locking, rwsem: Annotate inner lock as raw There is no reason to allow the lock protecting rwsems (the ownerless variant) to be preemptible on -rt. Convert it to raw. In mainline this change documents the low level nature of the lock - otherwise there's no functional difference. Lockdep and Sparse checking will work as usual. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- diff --git a/include/linux/rwsem-spinlock.h b/include/linux/rwsem-spinlock.h index 34701241b673..d5b13bc07a0b 100644 --- a/include/linux/rwsem-spinlock.h +++ b/include/linux/rwsem-spinlock.h @@ -22,7 +22,7 @@ */ struct rw_semaphore { __s32 activity; - spinlock_t wait_lock; + raw_spinlock_t wait_lock; struct list_head wait_list; #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 6a6741440cb7..63d406554391 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -25,7 +25,7 @@ struct rw_semaphore; /* All arch specific implementations share the same struct */ struct rw_semaphore { long count; - spinlock_t wait_lock; + raw_spinlock_t wait_lock; struct list_head wait_list; #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; @@ -56,9 +56,11 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem) # define __RWSEM_DEP_MAP_INIT(lockname) #endif -#define __RWSEM_INITIALIZER(name) \ - { RWSEM_UNLOCKED_VALUE, __SPIN_LOCK_UNLOCKED(name.wait_lock), \ - LIST_HEAD_INIT((name).wait_list) __RWSEM_DEP_MAP_INIT(name) } +#define __RWSEM_INITIALIZER(name) \ + { RWSEM_UNLOCKED_VALUE, \ + __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), \ + LIST_HEAD_INIT((name).wait_list) \ + __RWSEM_DEP_MAP_INIT(name) } #define DECLARE_RWSEM(name) \ struct rw_semaphore name = __RWSEM_INITIALIZER(name) diff --git a/lib/rwsem-spinlock.c b/lib/rwsem-spinlock.c index ffc9fc7f3b05..f2393c21fe85 100644 --- a/lib/rwsem-spinlock.c +++ b/lib/rwsem-spinlock.c @@ -22,9 +22,9 @@ int rwsem_is_locked(struct rw_semaphore *sem) int ret = 1; unsigned long flags; - if (spin_trylock_irqsave(&sem->wait_lock, flags)) { + if (raw_spin_trylock_irqsave(&sem->wait_lock, flags)) { ret = (sem->activity != 0); - spin_unlock_irqrestore(&sem->wait_lock, flags); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); } return ret; } @@ -44,7 +44,7 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name, lockdep_init_map(&sem->dep_map, name, key, 0); #endif sem->activity = 0; - spin_lock_init(&sem->wait_lock); + raw_spin_lock_init(&sem->wait_lock); INIT_LIST_HEAD(&sem->wait_list); } EXPORT_SYMBOL(__init_rwsem); @@ -145,12 +145,12 @@ void __sched __down_read(struct rw_semaphore *sem) struct task_struct *tsk; unsigned long flags; - spin_lock_irqsave(&sem->wait_lock, flags); + raw_spin_lock_irqsave(&sem->wait_lock, flags); if (sem->activity >= 0 && list_empty(&sem->wait_list)) { /* granted */ sem->activity++; - spin_unlock_irqrestore(&sem->wait_lock, flags); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); goto out; } @@ -165,7 +165,7 @@ void __sched __down_read(struct rw_semaphore *sem) list_add_tail(&waiter.list, &sem->wait_list); /* we don't need to touch the semaphore struct anymore */ - spin_unlock_irqrestore(&sem->wait_lock, flags); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); /* wait to be given the lock */ for (;;) { @@ -189,7 +189,7 @@ int __down_read_trylock(struct rw_semaphore *sem) int ret = 0; - spin_lock_irqsave(&sem->wait_lock, flags); + raw_spin_lock_irqsave(&sem->wait_lock, flags); if (sem->activity >= 0 && list_empty(&sem->wait_list)) { /* granted */ @@ -197,7 +197,7 @@ int __down_read_trylock(struct rw_semaphore *sem) ret = 1; } - spin_unlock_irqrestore(&sem->wait_lock, flags); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); return ret; } @@ -212,12 +212,12 @@ void __sched __down_write_nested(struct rw_semaphore *sem, int subclass) struct task_struct *tsk; unsigned long flags; - spin_lock_irqsave(&sem->wait_lock, flags); + raw_spin_lock_irqsave(&sem->wait_lock, flags); if (sem->activity == 0 && list_empty(&sem->wait_list)) { /* granted */ sem->activity = -1; - spin_unlock_irqrestore(&sem->wait_lock, flags); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); goto out; } @@ -232,7 +232,7 @@ void __sched __down_write_nested(struct rw_semaphore *sem, int subclass) list_add_tail(&waiter.list, &sem->wait_list); /* we don't need to touch the semaphore struct anymore */ - spin_unlock_irqrestore(&sem->wait_lock, flags); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); /* wait to be given the lock */ for (;;) { @@ -260,7 +260,7 @@ int __down_write_trylock(struct rw_semaphore *sem) unsigned long flags; int ret = 0; - spin_lock_irqsave(&sem->wait_lock, flags); + raw_spin_lock_irqsave(&sem->wait_lock, flags); if (sem->activity == 0 && list_empty(&sem->wait_list)) { /* granted */ @@ -268,7 +268,7 @@ int __down_write_trylock(struct rw_semaphore *sem) ret = 1; } - spin_unlock_irqrestore(&sem->wait_lock, flags); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); return ret; } @@ -280,12 +280,12 @@ void __up_read(struct rw_semaphore *sem) { unsigned long flags; - spin_lock_irqsave(&sem->wait_lock, flags); + raw_spin_lock_irqsave(&sem->wait_lock, flags); if (--sem->activity == 0 && !list_empty(&sem->wait_list)) sem = __rwsem_wake_one_writer(sem); - spin_unlock_irqrestore(&sem->wait_lock, flags); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); } /* @@ -295,13 +295,13 @@ void __up_write(struct rw_semaphore *sem) { unsigned long flags; - spin_lock_irqsave(&sem->wait_lock, flags); + raw_spin_lock_irqsave(&sem->wait_lock, flags); sem->activity = 0; if (!list_empty(&sem->wait_list)) sem = __rwsem_do_wake(sem, 1); - spin_unlock_irqrestore(&sem->wait_lock, flags); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); } /* @@ -312,12 +312,12 @@ void __downgrade_write(struct rw_semaphore *sem) { unsigned long flags; - spin_lock_irqsave(&sem->wait_lock, flags); + raw_spin_lock_irqsave(&sem->wait_lock, flags); sem->activity = 1; if (!list_empty(&sem->wait_list)) sem = __rwsem_do_wake(sem, 0); - spin_unlock_irqrestore(&sem->wait_lock, flags); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); } diff --git a/lib/rwsem.c b/lib/rwsem.c index aa7c3052261f..410aa1189b13 100644 --- a/lib/rwsem.c +++ b/lib/rwsem.c @@ -22,7 +22,7 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name, lockdep_init_map(&sem->dep_map, name, key, 0); #endif sem->count = RWSEM_UNLOCKED_VALUE; - spin_lock_init(&sem->wait_lock); + raw_spin_lock_init(&sem->wait_lock); INIT_LIST_HEAD(&sem->wait_list); } @@ -180,7 +180,7 @@ rwsem_down_failed_common(struct rw_semaphore *sem, set_task_state(tsk, TASK_UNINTERRUPTIBLE); /* set up my own style of waitqueue */ - spin_lock_irq(&sem->wait_lock); + raw_spin_lock_irq(&sem->wait_lock); waiter.task = tsk; waiter.flags = flags; get_task_struct(tsk); @@ -204,7 +204,7 @@ rwsem_down_failed_common(struct rw_semaphore *sem, adjustment == -RWSEM_ACTIVE_WRITE_BIAS) sem = __rwsem_do_wake(sem, RWSEM_WAKE_READ_OWNED); - spin_unlock_irq(&sem->wait_lock); + raw_spin_unlock_irq(&sem->wait_lock); /* wait to be given the lock */ for (;;) { @@ -245,13 +245,13 @@ struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem) { unsigned long flags; - spin_lock_irqsave(&sem->wait_lock, flags); + raw_spin_lock_irqsave(&sem->wait_lock, flags); /* do nothing if list empty */ if (!list_empty(&sem->wait_list)) sem = __rwsem_do_wake(sem, RWSEM_WAKE_ANY); - spin_unlock_irqrestore(&sem->wait_lock, flags); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); return sem; } @@ -265,13 +265,13 @@ struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem) { unsigned long flags; - spin_lock_irqsave(&sem->wait_lock, flags); + raw_spin_lock_irqsave(&sem->wait_lock, flags); /* do nothing if list empty */ if (!list_empty(&sem->wait_list)) sem = __rwsem_do_wake(sem, RWSEM_WAKE_READ_OWNED); - spin_unlock_irqrestore(&sem->wait_lock, flags); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); return sem; }