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Subject[PATCH 23/28] locking/lockdep: Update irqsafe lock bitmaps
Date
The bitmaps keep track of which locks are irqsafe. Update the bitmaps
when there is new irqsafe usage and when an irqsafe lock is zapped.

Signed-off-by: Yuyang Du <duyuyang@gmail.com>
---
kernel/locking/lockdep.c | 39 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 291cc9c..1b78216 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3107,6 +3107,7 @@ typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
int excl_bit = exclusive_bit(new_bit);
int read = new_bit & LOCK_USAGE_READ_MASK;
int dir = new_bit & LOCK_USAGE_DIR_MASK;
+ struct lock_class *lock = hlock_class(this);

/*
* mark USED_IN has to look forwards -- to ensure no dependency
@@ -3119,6 +3120,25 @@ typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
check_usage_backwards : check_usage_forwards;

/*
+ * The bit is already marked so that we update the bitmaps
+ * before validation.
+ */
+ if (!dir) {
+ unsigned long *bitmaps[4] = {
+ lock_classes_hardirq_safe,
+ lock_classes_hardirq_safe_read,
+ lock_classes_softirq_safe,
+ lock_classes_softirq_safe_read
+ };
+ int index = (new_bit >> 2) << 1;
+
+ if (read)
+ index += 1;
+
+ __set_bit(lock - lock_classes, bitmaps[index]);
+ }
+
+ /*
* Validate that this particular lock does not have conflicting
* usage states.
*/
@@ -3146,7 +3166,7 @@ typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
return 0;
}

- if (state_verbose(new_bit, hlock_class(this)))
+ if (state_verbose(new_bit, lock))
return 2;

return 1;
@@ -4650,6 +4670,22 @@ static void remove_class_from_lock_chains(struct pending_free *pf,
}
}

+static inline void remove_irqsafe_lock_bitmap(struct lock_class *class)
+{
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+ unsigned long usage = class->usage_mask;
+
+ if (usage & LOCKF_USED_IN_HARDIRQ)
+ __clear_bit(class - lock_classes, lock_classes_hardirq_safe);
+ if (usage & LOCKF_USED_IN_HARDIRQ_READ)
+ __clear_bit(class - lock_classes, lock_classes_hardirq_safe_read);
+ if (usage & LOCKF_USED_IN_SOFTIRQ)
+ __clear_bit(class - lock_classes, lock_classes_softirq_safe);
+ if (usage & LOCKF_USED_IN_SOFTIRQ_READ)
+ __clear_bit(class - lock_classes, lock_classes_softirq_safe_read);
+#endif
+}
+
/*
* Remove all references to a lock class. The caller must hold the graph lock.
*/
@@ -4680,6 +4716,7 @@ static void zap_class(struct pending_free *pf, struct lock_class *class)
WRITE_ONCE(class->name, NULL);
nr_lock_classes--;
__clear_bit(class - lock_classes, lock_classes_in_use);
+ remove_irqsafe_lock_bitmap(class);
} else {
WARN_ONCE(true, "%s() failed for class %s\n", __func__,
class->name);
--
1.8.3.1
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