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locking/rwlocks: introduce write_lock_nested

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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: Minchan Kim <minchan@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Sebastian 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Minchan Kim
2022-01-21 22:14:10 -08:00
committed by Linus Torvalds
parent c4549b8711
commit 4a57d6bbae
6 changed files with 47 additions and 0 deletions
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10
kernel/locking/spinlock.c
View File

@@ -300,6 +300,16 @@ void __lockfunc _raw_write_lock(rwlock_t *lock)
__raw_write_lock(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
#ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE

12
kernel/locking/spinlock_rt.c
View File

@@ -239,6 +239,18 @@ void __sched rt_write_lock(rwlock_t *rwlock)
}
EXPORT_SYMBOL(rt_write_lock);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
void __sched rt_write_lock_nested(rwlock_t *rwlock, int subclass)
{
rtlock_might_resched();
rwlock_acquire(&rwlock->dep_map, subclass, 0, _RET_IP_);
rwbase_write_lock(&rwlock->rwbase, TASK_RTLOCK_WAIT);
rcu_read_lock();
migrate_disable();
}
EXPORT_SYMBOL(rt_write_lock_nested);
#endif
void __sched rt_read_unlock(rwlock_t *rwlock)
{
rwlock_release(&rwlock->dep_map, _RET_IP_);