lockdep: add lock_class information to lock_chain and output it

This patch records array of lock_class into lock_chain, and export
lock_chain information via /proc/lockdep_chains.

It is based on x86/master branch of git-x86 tree, and has been tested
on x86_64 platform.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 91 insertions, 0 deletions

diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c
index 688c5f1940bd..14d052c8a835 100644
--- a/kernel/lockdep_proc.c
+++ b/kernel/lockdep_proc.c
@@ -178,6 +178,93 @@ static const struct file_operations proc_lockdep_operations = {
         .release        = seq_release,
 };
 
+static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
+{
+        struct lock_chain *chain;
+
+        (*pos)++;
+
+        if (v == SEQ_START_TOKEN)
+                chain = m->private;
+        else {
+                chain = v;
+
+                if (*pos < nr_lock_chains)
+                        chain = lock_chains + *pos;
+                else
+                        chain = NULL;
+        }
+
+        return chain;
+}
+
+static void *lc_start(struct seq_file *m, loff_t *pos)
+{
+        if (*pos == 0)
+                return SEQ_START_TOKEN;
+
+        if (*pos < nr_lock_chains)
+                return lock_chains + *pos;
+
+        return NULL;
+}
+
+static void lc_stop(struct seq_file *m, void *v)
+{
+}
+
+static int lc_show(struct seq_file *m, void *v)
+{
+        struct lock_chain *chain = v;
+        struct lock_class *class;
+        int i;
+
+        if (v == SEQ_START_TOKEN) {
+                seq_printf(m, "all lock chains:\n");
+                return 0;
+        }
+
+        seq_printf(m, "irq_context: %d\n", chain->irq_context);
+
+        for (i = 0; i < chain->depth; i++) {
+                class = lock_chain_get_class(chain, i);
+                seq_printf(m, "[%p] ", class->key);
+                print_name(m, class);
+                seq_puts(m, "\n");
+        }
+        seq_puts(m, "\n");
+
+        return 0;
+}
+
+static const struct seq_operations lockdep_chains_ops = {
+        .start  = lc_start,
+        .next   = lc_next,
+        .stop   = lc_stop,
+        .show   = lc_show,
+};
+
+static int lockdep_chains_open(struct inode *inode, struct file *file)
+{
+        int res = seq_open(file, &lockdep_chains_ops);
+        if (!res) {
+                struct seq_file *m = file->private_data;
+
+                if (nr_lock_chains)
+                        m->private = lock_chains;
+                else
+                        m->private = NULL;
+        }
+        return res;
+}
+
+static const struct file_operations proc_lockdep_chains_operations = {
+        .open           = lockdep_chains_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = seq_release,
+};
+
 static void lockdep_stats_debug_show(struct seq_file *m)
 {
 #ifdef CONFIG_DEBUG_LOCKDEP
@@ -294,6 +381,8 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
 #ifdef CONFIG_PROVE_LOCKING
         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
                         nr_lock_chains, MAX_LOCKDEP_CHAINS);
+        seq_printf(m, " dependency chain hlocks:       %11d [max: %lu]\n",
+                        atomic_read(&nr_chain_hlocks), MAX_LOCKDEP_CHAIN_HLOCKS);
 #endif
 
 #ifdef CONFIG_TRACE_IRQFLAGS
@@ -661,6 +750,8 @@ static const struct file_operations proc_lock_stat_operations = {
 static int __init lockdep_proc_init(void)
 {
         proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
+        proc_create("lockdep_chains", S_IRUSR, NULL,
+                    &proc_lockdep_chains_operations);
         proc_create("lockdep_stats", S_IRUSR, NULL,
                     &proc_lockdep_stats_operations);