[PATCH 6/9] PM: suspend_block: Add debugfs file

["Arve Hjønnevåg" <arve@android.com>]

Report active and inactive suspend blockers in
/sys/kernel/debug/suspend_blockers.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
---
 kernel/power/suspend_blocker.c |   45 ++++++++++++++++++++++++++++++++++++++-
 1 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/kernel/power/suspend_blocker.c b/kernel/power/suspend_blocker.c
index 94832ca..da7248a 100644
--- a/kernel/power/suspend_blocker.c
+++ b/kernel/power/suspend_blocker.c
@@ -18,6 +18,7 @@
 #include <linux/suspend.h>
 #include <linux/suspend_blocker.h>
 #include <linux/sysdev.h>
+#include <linux/debugfs.h>
 #include "power.h"
 
 enum {
@@ -42,6 +43,7 @@ struct workqueue_struct *suspend_work_queue;
 struct suspend_blocker main_suspend_blocker;
 static suspend_state_t requested_suspend_state = PM_SUSPEND_MEM;
 static bool enable_suspend_blockers;
+static struct dentry *suspend_blocker_stats_dentry;
 
 #define pr_info_time(fmt, args...) \
 	do { \
@@ -55,6 +57,21 @@ static bool enable_suspend_blockers;
 			tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec); \
 	} while (0);
 
+static int suspend_blocker_stats_show(struct seq_file *m, void *unused)
+{
+	unsigned long irqflags;
+	struct suspend_blocker *blocker;
+
+	seq_puts(m, "name\tactive\n");
+	spin_lock_irqsave(&list_lock, irqflags);
+	list_for_each_entry(blocker, &inactive_blockers, link)
+		seq_printf(m, "\"%s\"\t0\n", blocker->name);
+	list_for_each_entry(blocker, &active_blockers, link)
+		seq_printf(m, "\"%s\"\t1\n", blocker->name);
+	spin_unlock_irqrestore(&list_lock, irqflags);
+	return 0;
+}
+
 static void print_active_blockers_locked(void)
 {
 	struct suspend_blocker *blocker;
@@ -128,8 +145,8 @@ static struct sys_device suspend_block_sysdev = {
 /**
  * suspend_blocker_init() - Initialize a suspend blocker
  * @blocker:	The suspend blocker to initialize.
- * @name:	The name of the suspend blocker to show in debug messages.
- *
+ * @name:	The name of the suspend blocker to show in debug messages and
+ *		/sys/kernel/debug/suspend_blockers.
  * The suspend blocker struct and name must not be freed before calling
  * suspend_blocker_destroy.
  */
@@ -257,6 +274,19 @@ void request_suspend_state(suspend_state_t state)
 	spin_unlock_irqrestore(&state_lock, irqflags);
 }
 
+static int suspend_blocker_stats_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, suspend_blocker_stats_show, NULL);
+}
+
+static const struct file_operations suspend_blocker_stats_fops = {
+	.owner = THIS_MODULE,
+	.open = suspend_blocker_stats_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
 static int __init suspend_block_init(void)
 {
 	int ret;
@@ -292,8 +322,18 @@ err_sysdev_class_register:
 	return ret;
 }
 
+static int __init suspend_block_postcore_init(void)
+{
+	if (!suspend_work_queue)
+		return 0;
+	suspend_blocker_stats_dentry = debugfs_create_file("suspend_blockers",
+			S_IRUGO, NULL, NULL, &suspend_blocker_stats_fops);
+	return 0;
+}
+
 static void  __exit suspend_block_exit(void)
 {
+	debugfs_remove(suspend_blocker_stats_dentry);
 	destroy_workqueue(suspend_work_queue);
 	sysdev_unregister(&suspend_block_sysdev);
 	sysdev_class_unregister(&suspend_block_sysclass);
@@ -301,4 +341,5 @@ static void  __exit suspend_block_exit(void)
 }
 
 core_initcall(suspend_block_init);
+postcore_initcall(suspend_block_postcore_init);
 module_exit(suspend_block_exit);
-- 
1.6.1

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