change system file

hc

2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771

 kernel/kernel/locking/lockdep_proc.c
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@@ -24,14 +24,33 @@
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 #include "lockdep_internals.h"
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+/*
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+ * Since iteration of lock_classes is done without holding the lockdep lock,
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+ * it is not safe to iterate all_lock_classes list directly as the iteration
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+ * may branch off to free_lock_classes or the zapped list. Iteration is done
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+ * directly on the lock_classes array by checking the lock_classes_in_use
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+ * bitmap and max_lock_class_idx.
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+ */
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+#define iterate_lock_classes(idx, class)				\
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+	for (idx = 0, class = lock_classes; idx <= max_lock_class_idx;	\
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+	     idx++, class++)
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+
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 static void *l_next(struct seq_file *m, void *v, loff_t *pos)
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 {
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-	return seq_list_next(v, &all_lock_classes, pos);
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+	struct lock_class *class = v;
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+
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+	++class;
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+	*pos = class - lock_classes;
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+	return (*pos > max_lock_class_idx) ? NULL : class;
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 }
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 static void *l_start(struct seq_file *m, loff_t *pos)
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 {
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-	return seq_list_start_head(&all_lock_classes, *pos);
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+	unsigned long idx = *pos;
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+
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+	if (idx > max_lock_class_idx)
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+		return NULL;
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+	return lock_classes + idx;
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 }
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 static void l_stop(struct seq_file *m, void *v)
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@@ -57,18 +76,20 @@
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 static int l_show(struct seq_file *m, void *v)
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 {
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-	struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
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+	struct lock_class *class = v;
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 	struct lock_list *entry;
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 	char usage[LOCK_USAGE_CHARS];
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+	int idx = class - lock_classes;
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-	if (v == &all_lock_classes) {
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+	if (v == lock_classes)
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 		seq_printf(m, "all lock classes:\n");
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+
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+	if (!test_bit(idx, lock_classes_in_use))
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 		return 0;
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-	}
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 	seq_printf(m, "%p", class->key);
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 #ifdef CONFIG_DEBUG_LOCKDEP
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-	seq_printf(m, " OPS:%8ld", class->ops);
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+	seq_printf(m, " OPS:%8ld", debug_class_ops_read(class));
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 #endif
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 #ifdef CONFIG_PROVE_LOCKING
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 	seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
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@@ -104,18 +125,18 @@
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 #ifdef CONFIG_PROVE_LOCKING
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 static void *lc_start(struct seq_file *m, loff_t *pos)
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 {
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+	if (*pos < 0)
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+		return NULL;
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+
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 	if (*pos == 0)
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 		return SEQ_START_TOKEN;
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-	if (*pos - 1 < nr_lock_chains)
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-		return lock_chains + (*pos - 1);
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-
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-	return NULL;
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+	return lock_chains + (*pos - 1);
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 }
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 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
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 {
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-	(*pos)++;
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+	*pos = lockdep_next_lockchain(*pos - 1) + 1;
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 	return lc_start(m, pos);
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 }
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@@ -128,15 +149,22 @@
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 	struct lock_chain *chain = v;
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 	struct lock_class *class;
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 	int i;
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+	static const char * const irq_strs[] = {
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+		[0]			     = "0",
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+		[LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq",
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+		[LOCK_CHAIN_SOFTIRQ_CONTEXT] = "softirq",
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+		[LOCK_CHAIN_SOFTIRQ_CONTEXT|
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+		 LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq|softirq",
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+	};
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 	if (v == SEQ_START_TOKEN) {
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-		if (nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)
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+		if (!nr_free_chain_hlocks)
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 			seq_printf(m, "(buggered) ");
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 		seq_printf(m, "all lock chains:\n");
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 		return 0;
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 	}
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-	seq_printf(m, "irq_context: %d\n", chain->irq_context);
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+	seq_printf(m, "irq_context: %s\n", irq_strs[chain->irq_context]);
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 	for (i = 0; i < chain->depth; i++) {
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 		class = lock_chain_get_class(chain, i);
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@@ -211,8 +239,11 @@
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 #ifdef CONFIG_PROVE_LOCKING
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 	struct lock_class *class;
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+	unsigned long idx;
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-	list_for_each_entry(class, &all_lock_classes, lock_entry) {
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+	iterate_lock_classes(idx, class) {
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+		if (!test_bit(idx, lock_classes_in_use))
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+			continue;
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 		if (class->usage_mask == 0)
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 			nr_unused++;
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@@ -245,6 +276,7 @@
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 		sum_forward_deps += lockdep_count_forward_deps(class);
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 	}
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+
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 #ifdef CONFIG_DEBUG_LOCKDEP
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 	DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
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 #endif
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@@ -270,9 +302,13 @@
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 #ifdef CONFIG_PROVE_LOCKING
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 	seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
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-			nr_lock_chains, MAX_LOCKDEP_CHAINS);
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-	seq_printf(m, " dependency chain hlocks:       %11d [max: %lu]\n",
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-			nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
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+			lock_chain_count(), MAX_LOCKDEP_CHAINS);
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+	seq_printf(m, " dependency chain hlocks used:  %11lu [max: %lu]\n",
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+			MAX_LOCKDEP_CHAIN_HLOCKS -
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+			(nr_free_chain_hlocks + nr_lost_chain_hlocks),
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+			MAX_LOCKDEP_CHAIN_HLOCKS);
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+	seq_printf(m, " dependency chain hlocks lost:  %11u\n",
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+			nr_lost_chain_hlocks);
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 #endif
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 #ifdef CONFIG_TRACE_IRQFLAGS
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@@ -285,6 +321,12 @@
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 			nr_process_chains);
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 	seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
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 			nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
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+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
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+	seq_printf(m, " number of stack traces:        %11llu\n",
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+		   lockdep_stack_trace_count());
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+	seq_printf(m, " number of stack hash chains:   %11llu\n",
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+		   lockdep_stack_hash_count());
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+#endif
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 	seq_printf(m, " combined max dependencies:     %11u\n",
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 			(nr_hardirq_chains + 1) *
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 			(nr_softirq_chains + 1) *
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@@ -326,10 +368,24 @@
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 	seq_printf(m, " max bfs queue depth:           %11u\n",
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 			max_bfs_queue_depth);
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 #endif
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+	seq_printf(m, " max lock class index:          %11lu\n",
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+			max_lock_class_idx);
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 	lockdep_stats_debug_show(m);
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 	seq_printf(m, " debug_locks:                   %11u\n",
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 			debug_locks);
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+	/*
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+	 * Zappped classes and lockdep data buffers reuse statistics.
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+	 */
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+	seq_puts(m, "\n");
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+	seq_printf(m, " zapped classes:                %11lu\n",
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+			nr_zapped_classes);
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+#ifdef CONFIG_PROVE_LOCKING
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+	seq_printf(m, " zapped lock chains:            %11lu\n",
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+			nr_zapped_lock_chains);
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+	seq_printf(m, " large chain blocks:            %11u\n",
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+			nr_large_chain_blocks);
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+#endif
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 	return 0;
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 }
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@@ -399,7 +455,7 @@
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 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
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 {
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-	struct lockdep_subclass_key *ckey;
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+	const struct lockdep_subclass_key *ckey;
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 	struct lock_class_stats *stats;
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 	struct lock_class *class;
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 	const char *cname;
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@@ -591,12 +647,16 @@
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 	if (!res) {
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 		struct lock_stat_data *iter = data->stats;
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 		struct seq_file *m = file->private_data;
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+		unsigned long idx;
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-		list_for_each_entry(class, &all_lock_classes, lock_entry) {
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+		iterate_lock_classes(idx, class) {
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+			if (!test_bit(idx, lock_classes_in_use))
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+				continue;
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 			iter->class = class;
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 			iter->stats = lock_stats(class);
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 			iter++;
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 		}
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+
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 		data->iter_end = iter;
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 		sort(data->stats, data->iter_end - data->stats,
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@@ -614,6 +674,7 @@
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 			       size_t count, loff_t *ppos)
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 {
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 	struct lock_class *class;
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+	unsigned long idx;
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 	char c;
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 	if (count) {
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@@ -623,8 +684,11 @@
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 		if (c != '0')
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 			return count;
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-		list_for_each_entry(class, &all_lock_classes, lock_entry)
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+		iterate_lock_classes(idx, class) {
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+			if (!test_bit(idx, lock_classes_in_use))
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+				continue;
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 			clear_lock_stats(class);
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+		}
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 	}
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 	return count;
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 }
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@@ -637,12 +701,12 @@
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 	return seq_release(inode, file);
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 }
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-static const struct file_operations proc_lock_stat_operations = {
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-	.open		= lock_stat_open,
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-	.write		= lock_stat_write,
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-	.read		= seq_read,
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-	.llseek		= seq_lseek,
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-	.release	= lock_stat_release,
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+static const struct proc_ops lock_stat_proc_ops = {
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+	.proc_open	= lock_stat_open,
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+	.proc_write	= lock_stat_write,
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+	.proc_read	= seq_read,
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+	.proc_lseek	= seq_lseek,
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+	.proc_release	= lock_stat_release,
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 };
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 #endif /* CONFIG_LOCK_STAT */
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@@ -654,8 +718,7 @@
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 #endif
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 	proc_create_single("lockdep_stats", S_IRUSR, NULL, lockdep_stats_show);
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 #ifdef CONFIG_LOCK_STAT
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-	proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
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-		    &proc_lock_stat_operations);
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+	proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL, &lock_stat_proc_ops);
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 #endif
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 	return 0;