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Subject: rt/rwlock: Remove recursive support
From: Thomas Gleixner <tglx@linutronix.de>
Date: Fri, 28 Jul 2017 12:35:23 +0200
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/rwlock_types_rt.h | 1
kernel/locking/rt.c | 56 ++++++++--------------------------------
2 files changed, 12 insertions(+), 45 deletions(-)
--- a/include/linux/rwlock_types_rt.h
+++ b/include/linux/rwlock_types_rt.h
@@ -10,7 +10,6 @@
*/
typedef struct {
struct rt_mutex lock;
- int read_depth;
unsigned int break_lock;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
--- a/kernel/locking/rt.c
+++ b/kernel/locking/rt.c
@@ -211,46 +211,28 @@ int __lockfunc rt_write_trylock(rwlock_t
rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
else
migrate_enable();
-
return ret;
}
EXPORT_SYMBOL(rt_write_trylock);
int __lockfunc rt_write_trylock_irqsave(rwlock_t *rwlock, unsigned long *flags)
{
- int ret;
-
*flags = 0;
- ret = rt_write_trylock(rwlock);
- return ret;
+ return rt_write_trylock(rwlock);
}
EXPORT_SYMBOL(rt_write_trylock_irqsave);
int __lockfunc rt_read_trylock(rwlock_t *rwlock)
{
struct rt_mutex *lock = &rwlock->lock;
- int ret = 1;
-
- /*
- * recursive read locks succeed when current owns the lock,
- * but not when read_depth == 0 which means that the lock is
- * write locked.
- */
- if (rt_mutex_owner(lock) != current) {
- migrate_disable();
- ret = rt_mutex_trylock(lock);
- if (ret)
- rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
- else
- migrate_enable();
-
- } else if (!rwlock->read_depth) {
- ret = 0;
- }
+ int ret;
+ migrate_disable();
+ ret = rt_mutex_trylock(lock);
if (ret)
- rwlock->read_depth++;
-
+ rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
+ else
+ migrate_enable();
return ret;
}
EXPORT_SYMBOL(rt_read_trylock);
@@ -266,17 +248,9 @@ void __lockfunc rt_read_lock(rwlock_t *r
{
struct rt_mutex *lock = &rwlock->lock;
-
- /*
- * recursive read locks succeed when current owns the lock
- */
- if (rt_mutex_owner(lock) != current) {
- rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
- __rt_spin_lock(lock);
- }
- rwlock->read_depth++;
+ rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
+ __rt_spin_lock(lock);
}
-
EXPORT_SYMBOL(rt_read_lock);
void __lockfunc rt_write_unlock(rwlock_t *rwlock)
@@ -290,19 +264,15 @@ EXPORT_SYMBOL(rt_write_unlock);
void __lockfunc rt_read_unlock(rwlock_t *rwlock)
{
- /* Release the lock only when read_depth is down to 0 */
- if (--rwlock->read_depth == 0) {
- rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
- __rt_spin_unlock(&rwlock->lock);
- migrate_enable();
- }
+ rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
+ __rt_spin_unlock(&rwlock->lock);
+ migrate_enable();
}
EXPORT_SYMBOL(rt_read_unlock);
unsigned long __lockfunc rt_write_lock_irqsave(rwlock_t *rwlock)
{
rt_write_lock(rwlock);
-
return 0;
}
EXPORT_SYMBOL(rt_write_lock_irqsave);
@@ -310,7 +280,6 @@ EXPORT_SYMBOL(rt_write_lock_irqsave);
unsigned long __lockfunc rt_read_lock_irqsave(rwlock_t *rwlock)
{
rt_read_lock(rwlock);
-
return 0;
}
EXPORT_SYMBOL(rt_read_lock_irqsave);
@@ -325,7 +294,6 @@ void __rt_rwlock_init(rwlock_t *rwlock,
lockdep_init_map(&rwlock->dep_map, name, key, 0);
#endif
rwlock->lock.save_state = 1;
- rwlock->read_depth = 0;
}
EXPORT_SYMBOL(__rt_rwlock_init);
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