Commit 4a57d6bb authored by Minchan Kim's avatar Minchan Kim Committed by Linus Torvalds
Browse files

locking/rwlocks: introduce write_lock_nested 

In preparation for converting bit_spin_lock to rwlock in zsmalloc so
that multiple writers of zspages can run at the same time but those
zspages are supposed to be different zspage instance.  Thus, it's not
deadlock.  This patch adds write_lock_nested to support the case for
LOCKDEP.

[minchan@kernel.org: fix write_lock_nested for RT]
  Link: https://lkml.kernel.org/r/YZfrMTAXV56HFWJY@google.com
[bigeasy@linutronix.de: fixup write_lock_nested() implementation]
  Link: https://lkml.kernel.org/r/20211123170134.y6xb7pmpgdn4m3bn@linutronix.de

Link: https://lkml.kernel.org/r/20211115185909.3949505-8-minchan@kernel.org


Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c4549b87

include/linux/rwlock.h

+6 −0
Original line number Original line Diff line number Diff line
@@ -55,6 +55,12 @@ do { \ 
#define write_lock(lock)	_raw_write_lock(lock)

#define write_lock(lock)	_raw_write_lock(lock)

#define read_lock(lock)		_raw_read_lock(lock)

#define read_lock(lock)		_raw_read_lock(lock)





#ifdef CONFIG_DEBUG_LOCK_ALLOC

#define write_lock_nested(lock, subclass)	_raw_write_lock_nested(lock, subclass)

#else

#define write_lock_nested(lock, subclass)	_raw_write_lock(lock)

#endif



#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)

#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)





#define read_lock_irqsave(lock, flags)			\

#define read_lock_irqsave(lock, flags)			\

include/linux/rwlock_api_smp.h

+8 −0
Original line number Original line Diff line number Diff line
@@ -17,6 +17,7 @@ 




void __lockfunc _raw_read_lock(rwlock_t *lock)		__acquires(lock);

void __lockfunc _raw_read_lock(rwlock_t *lock)		__acquires(lock);

void __lockfunc _raw_write_lock(rwlock_t *lock)		__acquires(lock);

void __lockfunc _raw_write_lock(rwlock_t *lock)		__acquires(lock);

void __lockfunc _raw_write_lock_nested(rwlock_t *lock, int subclass)	__acquires(lock);

void __lockfunc _raw_read_lock_bh(rwlock_t *lock)	__acquires(lock);

void __lockfunc _raw_read_lock_bh(rwlock_t *lock)	__acquires(lock);

void __lockfunc _raw_write_lock_bh(rwlock_t *lock)	__acquires(lock);

void __lockfunc _raw_write_lock_bh(rwlock_t *lock)	__acquires(lock);

void __lockfunc _raw_read_lock_irq(rwlock_t *lock)	__acquires(lock);

void __lockfunc _raw_read_lock_irq(rwlock_t *lock)	__acquires(lock);
@@ -209,6 +210,13 @@ static inline void __raw_write_lock(rwlock_t *lock) 
	LOCK_CONTENDED(lock, do_raw_write_trylock, do_raw_write_lock);

	LOCK_CONTENDED(lock, do_raw_write_trylock, do_raw_write_lock);

}

}





static inline void __raw_write_lock_nested(rwlock_t *lock, int subclass)

{

	preempt_disable();

	rwlock_acquire(&lock->dep_map, subclass, 0, _RET_IP_);

	LOCK_CONTENDED(lock, do_raw_write_trylock, do_raw_write_lock);

}



#endif /* !CONFIG_GENERIC_LOCKBREAK || CONFIG_DEBUG_LOCK_ALLOC */

#endif /* !CONFIG_GENERIC_LOCKBREAK || CONFIG_DEBUG_LOCK_ALLOC */





static inline void __raw_write_unlock(rwlock_t *lock)

static inline void __raw_write_unlock(rwlock_t *lock)

include/linux/rwlock_rt.h

+10 −0
Original line number Original line Diff line number Diff line
@@ -28,6 +28,7 @@ extern void rt_read_lock(rwlock_t *rwlock); 
extern int rt_read_trylock(rwlock_t *rwlock);

extern int rt_read_trylock(rwlock_t *rwlock);

extern void rt_read_unlock(rwlock_t *rwlock);

extern void rt_read_unlock(rwlock_t *rwlock);

extern void rt_write_lock(rwlock_t *rwlock);

extern void rt_write_lock(rwlock_t *rwlock);

extern void rt_write_lock_nested(rwlock_t *rwlock, int subclass);

extern int rt_write_trylock(rwlock_t *rwlock);

extern int rt_write_trylock(rwlock_t *rwlock);

extern void rt_write_unlock(rwlock_t *rwlock);

extern void rt_write_unlock(rwlock_t *rwlock);
@@ -83,6 +84,15 @@ static __always_inline void write_lock(rwlock_t *rwlock) 
	rt_write_lock(rwlock);

	rt_write_lock(rwlock);

}

}





#ifdef CONFIG_DEBUG_LOCK_ALLOC

static __always_inline void write_lock_nested(rwlock_t *rwlock, int subclass)

{

	rt_write_lock_nested(rwlock, subclass);

}

#else

#define write_lock_nested(lock, subclass)	rt_write_lock(((void)(subclass), (lock)))

#endif



static __always_inline void write_lock_bh(rwlock_t *rwlock)

static __always_inline void write_lock_bh(rwlock_t *rwlock)

{

{

	local_bh_disable();

	local_bh_disable();

include/linux/spinlock_api_up.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -59,6 +59,7 @@ 
#define _raw_spin_lock_nested(lock, subclass)	__LOCK(lock)

#define _raw_spin_lock_nested(lock, subclass)	__LOCK(lock)

#define _raw_read_lock(lock)			__LOCK(lock)

#define _raw_read_lock(lock)			__LOCK(lock)

#define _raw_write_lock(lock)			__LOCK(lock)

#define _raw_write_lock(lock)			__LOCK(lock)

#define _raw_write_lock_nested(lock, subclass)	__LOCK(lock)

#define _raw_spin_lock_bh(lock)			__LOCK_BH(lock)

#define _raw_spin_lock_bh(lock)			__LOCK_BH(lock)

#define _raw_read_lock_bh(lock)			__LOCK_BH(lock)

#define _raw_read_lock_bh(lock)			__LOCK_BH(lock)

#define _raw_write_lock_bh(lock)		__LOCK_BH(lock)

#define _raw_write_lock_bh(lock)		__LOCK_BH(lock)

kernel/locking/spinlock.c

+10 −0
Original line number Original line Diff line number Diff line
@@ -300,6 +300,16 @@ void __lockfunc _raw_write_lock(rwlock_t *lock) 
	__raw_write_lock(lock);

	__raw_write_lock(lock);

}

}

EXPORT_SYMBOL(_raw_write_lock);

EXPORT_SYMBOL(_raw_write_lock);



#ifndef CONFIG_DEBUG_LOCK_ALLOC

#define __raw_write_lock_nested(lock, subclass)	__raw_write_lock(((void)(subclass), (lock)))

#endif



void __lockfunc _raw_write_lock_nested(rwlock_t *lock, int subclass)

{

	__raw_write_lock_nested(lock, subclass);

}

EXPORT_SYMBOL(_raw_write_lock_nested);

#endif

#endif





#ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE

#ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE