The patch titled
Subject: locking/rwlocks: introduce write_lock_nested
has been added to the -mm tree. Its filename is
locking-rwlocks-introduce-write_lock_nested.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/locking-rwlocks-introduce-write_lock_nested.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/locking-rwlocks-introduce-write_lock_nested.patch
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------------------------------------------------------
From: Minchan Kim <minchan@xxxxxxxxxx>
Subject: 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.
Link: https://lkml.kernel.org/r/20211115185909.3949505-8-minchan@xxxxxxxxxx
Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Mike Galbraith <umgwanakikbuti@xxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/rwlock.h | 6 ++++++
include/linux/rwlock_api_smp.h | 9 +++++++++
include/linux/rwlock_rt.h | 6 ++++++
include/linux/spinlock_api_up.h | 1 +
kernel/locking/spinlock.c | 6 ++++++
kernel/locking/spinlock_rt.c | 12 ++++++++++++
6 files changed, 40 insertions(+)
--- a/include/linux/rwlock_api_smp.h~locking-rwlocks-introduce-write_lock_nested
+++ a/include/linux/rwlock_api_smp.h
@@ -17,6 +17,7 @@
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_nested(rwlock_t *lock, int subclass) __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_read_lock_irq(rwlock_t *lock) __acquires(lock);
@@ -46,6 +47,7 @@ _raw_write_unlock_irqrestore(rwlock_t *l
#ifdef CONFIG_INLINE_WRITE_LOCK
#define _raw_write_lock(lock) __raw_write_lock(lock)
+#define _raw_write_lock_nested(lock, subclass) __raw_write_lock_nested(lock, subclass)
#endif
#ifdef CONFIG_INLINE_READ_LOCK_BH
@@ -209,6 +211,13 @@ static inline void __raw_write_lock(rwlo
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 */
static inline void __raw_write_unlock(rwlock_t *lock)
--- a/include/linux/rwlock.h~locking-rwlocks-introduce-write_lock_nested
+++ a/include/linux/rwlock.h
@@ -55,6 +55,12 @@ do { \
#define write_lock(lock) _raw_write_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)
#define read_lock_irqsave(lock, flags) \
--- a/include/linux/rwlock_rt.h~locking-rwlocks-introduce-write_lock_nested
+++ a/include/linux/rwlock_rt.h
@@ -28,6 +28,7 @@ extern void rt_read_lock(rwlock_t *rwloc
extern int rt_read_trylock(rwlock_t *rwlock);
extern void rt_read_unlock(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 void rt_write_unlock(rwlock_t *rwlock);
@@ -83,6 +84,11 @@ static __always_inline void write_lock(r
rt_write_lock(rwlock);
}
+static __always_inline void write_lock_nested(rwlock_t *rwlock, int subclass)
+{
+ rt_write_lock_nested(rwlock, subclass);
+}
+
static __always_inline void write_lock_bh(rwlock_t *rwlock)
{
local_bh_disable();
--- a/include/linux/spinlock_api_up.h~locking-rwlocks-introduce-write_lock_nested
+++ a/include/linux/spinlock_api_up.h
@@ -59,6 +59,7 @@
#define _raw_spin_lock_nested(lock, subclass) __LOCK(lock)
#define _raw_read_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_read_lock_bh(lock) __LOCK_BH(lock)
#define _raw_write_lock_bh(lock) __LOCK_BH(lock)
--- a/kernel/locking/spinlock.c~locking-rwlocks-introduce-write_lock_nested
+++ a/kernel/locking/spinlock.c
@@ -300,6 +300,12 @@ void __lockfunc _raw_write_lock(rwlock_t
__raw_write_lock(lock);
}
EXPORT_SYMBOL(_raw_write_lock);
+
+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
--- a/kernel/locking/spinlock_rt.c~locking-rwlocks-introduce-write_lock_nested
+++ a/kernel/locking/spinlock_rt.c
@@ -239,6 +239,18 @@ void __sched rt_write_lock(rwlock_t *rwl
}
EXPORT_SYMBOL(rt_write_lock);
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __sched rt_write_lock_nested(rwlock_t *rwlock, int subclass)
+{
+ ___might_sleep(__FILE__, __LINE__, 0);
+ 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_);
_
Patches currently in -mm which might be from minchan@xxxxxxxxxx are
zsmalloc-introduce-some-helper-functions.patch
zsmalloc-rename-zs_stat_type-to-class_stat_type.patch
zsmalloc-decouple-class-actions-from-zspage-works.patch
zsmalloc-introduce-obj_allocated.patch
zsmalloc-move-huge-compressed-obj-from-page-to-zspage.patch
zsmalloc-remove-zspage-isolation-for-migration.patch
locking-rwlocks-introduce-write_lock_nested.patch
zsmalloc-replace-per-zpage-lock-with-pool-migrate_lock.patch
