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authorThomas Gleixner <tglx@linutronix.de>2010-02-24 11:54:54 +0300
committerIngo Molnar <mingo@elte.hu>2011-09-13 13:11:59 +0400
commitddb6c9b58a19edcfac93ac670b066c836ff729f1 (patch)
tree70a9ab2dde08671a050424b0d70fa535472e1345
parent8292c9e15c3b069459794a04f5e2cf0d5665ddc4 (diff)
downloadlinux-ddb6c9b58a19edcfac93ac670b066c836ff729f1.tar.xz
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 <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--include/linux/rwsem-spinlock.h2
-rw-r--r--include/linux/rwsem.h10
-rw-r--r--lib/rwsem-spinlock.c38
-rw-r--r--lib/rwsem.c14
4 files changed, 33 insertions, 31 deletions
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;
}