linux-kernel - [PATCH 23/28] locking/lockdep: Update irqsafe lock bitmaps

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Message-Id: <20190424101934.51535-24-duyuyang@gmail.com>
Date:   Wed, 24 Apr 2019 18:19:29 +0800
From:   Yuyang Du <duyuyang@...il.com>
To:     peterz@...radead.org, will.deacon@....com, mingo@...nel.org
Cc:     bvanassche@....org, ming.lei@...hat.com, frederic@...nel.org,
        tglx@...utronix.de, linux-kernel@...r.kernel.org,
        Yuyang Du <duyuyang@...il.com>
Subject: [PATCH 23/28] locking/lockdep: Update irqsafe lock bitmaps

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@...il.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