3 files changed, 8 insertions, 2 deletions

diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c
index dcb16b5cbec0..e5b1b60757bb 100644
--- a/drivers/input/serio/libps2.c
+++ b/drivers/input/serio/libps2.c
@@ -189,7 +189,7 @@ int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
                 return -1;
         }
 
-        mutex_lock_nested(&ps2dev->cmd_mutex, SINGLE_DEPTH_NESTING);
+        mutex_lock(&ps2dev->cmd_mutex);
 
         serio_pause_rx(ps2dev->serio);
         ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
@@ -296,6 +296,7 @@ EXPORT_SYMBOL(ps2_schedule_command);
 void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
 {
         mutex_init(&ps2dev->cmd_mutex);
+        lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
         init_waitqueue_head(&ps2dev->wait);
         ps2dev->serio = serio;
 }
diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
index 960fae3c3cea..480fdc5d20b3 100644
--- a/drivers/input/serio/serio.c
+++ b/drivers/input/serio/serio.c
@@ -538,8 +538,12 @@ static void serio_init_port(struct serio *serio)
                  "serio%ld", (long)atomic_inc_return(&serio_no) - 1);
         serio->dev.bus = &serio_bus;
         serio->dev.release = serio_release_port;
-        if (serio->parent)
+        if (serio->parent) {
                 serio->dev.parent = &serio->parent->dev;
+                serio->depth = serio->parent->depth + 1;
+        } else
+                serio->depth = 0;
+        lockdep_set_subclass(&serio->lock, serio->depth);
 }
 
 /*
diff --git a/include/linux/serio.h b/include/linux/serio.h
index 3a697cc6ecae..b99c5ca9708d 100644
--- a/include/linux/serio.h
+++ b/include/linux/serio.h
@@ -41,6 +41,7 @@ struct serio {
         void (*stop)(struct serio *);
 
         struct serio *parent, *child;
+        unsigned int depth;             /* level of nesting in serio hierarchy */
 
         struct serio_driver *drv;       /* accessed from interrupt, must be protected by serio->lock and serio->sem */
         struct mutex drv_mutex;         /* protects serio->drv so attributes can pin driver */