1 files changed, 2 insertions, 0 deletions

diff --git a/include/sound/core.h b/include/sound/core.h
index eedda2cdfe57..1df3f2fe5350 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -116,6 +116,8 @@ struct snd_card {
         int user_ctl_count;             /* count of all user controls */
         struct list_head controls;      /* all controls for this card */
         struct list_head ctl_files;     /* active control files */
+        struct mutex user_ctl_lock;     /* protects user controls against
+                                           concurrent access */
 
         struct snd_info_entry *proc_root;       /* root for soundcard specific files */
         struct snd_info_entry *proc_id; /* the card id */