The patch titled
lockdep: spin_lock_nest_lock()
has been added to the -mm tree. Its filename is
lockdep-spin_lock_nest_lock.patch
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------------------------------------------------------
Subject: lockdep: spin_lock_nest_lock()
From: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Expose the new lock protection lock.
This can be used to annotate places where we take multiple locks of the
same class and avoid deadlocks by always taking another (top-level) lock
first.
NOTE: we're still bound to the MAX_LOCK_DEPTH (48) limit.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/lockdep.h | 2 ++
include/linux/spinlock.h | 6 ++++++
kernel/spinlock.c | 11 +++++++++++
3 files changed, 19 insertions(+)
diff -puN include/linux/lockdep.h~lockdep-spin_lock_nest_lock include/linux/lockdep.h
--- a/include/linux/lockdep.h~lockdep-spin_lock_nest_lock
+++ a/include/linux/lockdep.h
@@ -410,8 +410,10 @@ static inline void print_irqtrace_events
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# ifdef CONFIG_PROVE_LOCKING
# define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i)
+# define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i)
# else
# define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i)
+# define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, NULL, i)
# endif
# define spin_release(l, n, i) lock_release(l, n, i)
#else
diff -puN include/linux/spinlock.h~lockdep-spin_lock_nest_lock include/linux/spinlock.h
--- a/include/linux/spinlock.h~lockdep-spin_lock_nest_lock
+++ a/include/linux/spinlock.h
@@ -183,8 +183,14 @@ do { \
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
+# define spin_lock_nest_lock(lock, nest_lock) \
+ do { \
+ typecheck(struct lockdep_map *, &nest_lock->dep_map); \
+ _spin_lock_nest_lock(lock, &nest_lock->dep_map); \
+ } while (0)
#else
# define spin_lock_nested(lock, subclass) _spin_lock(lock)
+# define spin_lock_nest_lock(lock, nest_lock) _spin_lock(lock)
#endif
#define write_lock(lock) _write_lock(lock)
diff -puN kernel/spinlock.c~lockdep-spin_lock_nest_lock kernel/spinlock.c
--- a/kernel/spinlock.c~lockdep-spin_lock_nest_lock
+++ a/kernel/spinlock.c
@@ -292,6 +292,7 @@ void __lockfunc _spin_lock_nested(spinlo
}
EXPORT_SYMBOL(_spin_lock_nested);
+
unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass)
{
unsigned long flags;
@@ -314,6 +315,16 @@ unsigned long __lockfunc _spin_lock_irqs
EXPORT_SYMBOL(_spin_lock_irqsave_nested);
+void __lockfunc _spin_lock_nest_lock(spinlock_t *lock,
+ struct lockdep_map *nest_lock)
+{
+ preempt_disable();
+ spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
+ LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
+}
+
+EXPORT_SYMBOL(_spin_lock_nest_lock)
+
#endif
void __lockfunc _spin_unlock(spinlock_t *lock)
_
Patches currently in -mm which might be from a.p.zijlstra@xxxxxxxxx are
linux-next.patch
sched-type-fix.patch
lockdep-fix-combinatorial-explosion-in-lock-subgraph-traversal.patch
lockdep-lock_set_subclass-reset-a-held-locks-subclass.patch
lockdep-re-annotate-scheduler-runqueues.patch
lockdep-shrink-held_lock-structure.patch
lockdep-map_acquire.patch
lockdep-lock-protection-locks.patch
lockdep-spin_lock_nest_lock.patch
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