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KAGA-KOKOIngo Molnar
KAGA-KOKO
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Ingo Molnar
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locking/spinlock: Provide RT variant header: <linux/spinlock_rt.h>
Provide the necessary wrappers around the actual rtmutex based spinlock implementation. Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Link: https://lore.kernel.org/r/[email protected]
1 parent 051790e commit 342a932

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‎include/linux/spinlock.h

Lines changed: 10 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -312,8 +312,10 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
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1 : ({ local_irq_restore(flags); 0; }); \
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})
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/* Include rwlock functions */
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#ifndef CONFIG_PREEMPT_RT
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/* Include rwlock functions for !RT */
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#include <linux/rwlock.h>
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#endif
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/*
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* Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
@@ -324,6 +326,9 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
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# include <linux/spinlock_api_up.h>
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#endif
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/* Non PREEMPT_RT kernel, map to raw spinlocks: */
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#ifndef CONFIG_PREEMPT_RT
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/*
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* Map the spin_lock functions to the raw variants for PREEMPT_RT=n
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*/
@@ -458,6 +463,10 @@ static __always_inline int spin_is_contended(spinlock_t *lock)
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#define assert_spin_locked(lock) assert_raw_spin_locked(&(lock)->rlock)
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#else /* !CONFIG_PREEMPT_RT */
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# include <linux/spinlock_rt.h>
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#endif /* CONFIG_PREEMPT_RT */
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/*
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* Pull the atomic_t declaration:
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* (asm-mips/atomic.h needs above definitions)

‎include/linux/spinlock_api_smp.h

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -187,6 +187,9 @@ static inline int __raw_spin_trylock_bh(raw_spinlock_t *lock)
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return 0;
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}
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/* PREEMPT_RT has its own rwlock implementation */
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#ifndef CONFIG_PREEMPT_RT
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#include <linux/rwlock_api_smp.h>
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#endif
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#endif /* __LINUX_SPINLOCK_API_SMP_H */

‎include/linux/spinlock_rt.h

Lines changed: 149 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,149 @@
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// SPDX-License-Identifier: GPL-2.0-only
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#ifndef __LINUX_SPINLOCK_RT_H
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#define __LINUX_SPINLOCK_RT_H
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#ifndef __LINUX_SPINLOCK_H
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#error Do not include directly. Use spinlock.h
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#endif
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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extern void __rt_spin_lock_init(spinlock_t *lock, const char *name,
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struct lock_class_key *key);
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#else
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static inline void __rt_spin_lock_init(spinlock_t *lock, const char *name,
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struct lock_class_key *key)
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{
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}
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#endif
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#define spin_lock_init(slock) \
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do { \
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static struct lock_class_key __key; \
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\
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rt_mutex_base_init(&(slock)->lock); \
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__rt_spin_lock_init(slock, #slock, &__key); \
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} while (0)
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extern void rt_spin_lock(spinlock_t *lock);
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extern void rt_spin_lock_nested(spinlock_t *lock, int subclass);
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extern void rt_spin_lock_nest_lock(spinlock_t *lock, struct lockdep_map *nest_lock);
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extern void rt_spin_unlock(spinlock_t *lock);
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extern void rt_spin_lock_unlock(spinlock_t *lock);
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extern int rt_spin_trylock_bh(spinlock_t *lock);
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extern int rt_spin_trylock(spinlock_t *lock);
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static __always_inline void spin_lock(spinlock_t *lock)
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{
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rt_spin_lock(lock);
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}
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#ifdef CONFIG_LOCKDEP
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# define __spin_lock_nested(lock, subclass) \
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rt_spin_lock_nested(lock, subclass)
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# define __spin_lock_nest_lock(lock, nest_lock) \
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do { \
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typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \
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rt_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
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} while (0)
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# define __spin_lock_irqsave_nested(lock, flags, subclass) \
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do { \
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typecheck(unsigned long, flags); \
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flags = 0; \
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__spin_lock_nested(lock, subclass); \
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} while (0)
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#else
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/*
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* Always evaluate the 'subclass' argument to avoid that the compiler
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* warns about set-but-not-used variables when building with
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* CONFIG_DEBUG_LOCK_ALLOC=n and with W=1.
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*/
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# define __spin_lock_nested(lock, subclass) spin_lock(((void)(subclass), (lock)))
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# define __spin_lock_nest_lock(lock, subclass) spin_lock(((void)(subclass), (lock)))
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# define __spin_lock_irqsave_nested(lock, flags, subclass) \
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spin_lock_irqsave(((void)(subclass), (lock)), flags)
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#endif
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#define spin_lock_nested(lock, subclass) \
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__spin_lock_nested(lock, subclass)
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#define spin_lock_nest_lock(lock, nest_lock) \
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__spin_lock_nest_lock(lock, nest_lock)
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#define spin_lock_irqsave_nested(lock, flags, subclass) \
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__spin_lock_irqsave_nested(lock, flags, subclass)
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static __always_inline void spin_lock_bh(spinlock_t *lock)
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{
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/* Investigate: Drop bh when blocking ? */
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local_bh_disable();
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rt_spin_lock(lock);
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}
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static __always_inline void spin_lock_irq(spinlock_t *lock)
85+
{
86+
rt_spin_lock(lock);
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}
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#define spin_lock_irqsave(lock, flags) \
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do { \
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typecheck(unsigned long, flags); \
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flags = 0; \
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spin_lock(lock); \
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} while (0)
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static __always_inline void spin_unlock(spinlock_t *lock)
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{
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rt_spin_unlock(lock);
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}
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static __always_inline void spin_unlock_bh(spinlock_t *lock)
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{
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rt_spin_unlock(lock);
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local_bh_enable();
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}
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static __always_inline void spin_unlock_irq(spinlock_t *lock)
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{
109+
rt_spin_unlock(lock);
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}
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static __always_inline void spin_unlock_irqrestore(spinlock_t *lock,
113+
unsigned long flags)
114+
{
115+
rt_spin_unlock(lock);
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}
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#define spin_trylock(lock) \
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__cond_lock(lock, rt_spin_trylock(lock))
120+
121+
#define spin_trylock_bh(lock) \
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__cond_lock(lock, rt_spin_trylock_bh(lock))
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#define spin_trylock_irq(lock) \
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__cond_lock(lock, rt_spin_trylock(lock))
126+
127+
#define __spin_trylock_irqsave(lock, flags) \
128+
({ \
129+
int __locked; \
130+
\
131+
typecheck(unsigned long, flags); \
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flags = 0; \
133+
__locked = spin_trylock(lock); \
134+
__locked; \
135+
})
136+
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#define spin_trylock_irqsave(lock, flags) \
138+
__cond_lock(lock, __spin_trylock_irqsave(lock, flags))
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140+
#define spin_is_contended(lock) (((void)(lock), 0))
141+
142+
static inline int spin_is_locked(spinlock_t *lock)
143+
{
144+
return rt_mutex_base_is_locked(&lock->lock);
145+
}
146+
147+
#define assert_spin_locked(lock) BUG_ON(!spin_is_locked(lock))
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149+
#endif

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