[S390] cio: ccwgroup register vs. unregister.

Introduce a mutex for struct ccwgroup to prevent simuntaneous
register/unregister on the same ccwgroup device.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/asm-s390/ccwgroup.h b/include/asm-s390/ccwgroup.h
index d2f9c0d53a97..925b3ddfa141 100644
--- a/include/asm-s390/ccwgroup.h
+++ b/include/asm-s390/ccwgroup.h
@@ -11,6 +11,7 @@ struct ccwgroup_device {
                 CCWGROUP_ONLINE,
         } state;
         atomic_t onoff;
+        struct mutex reg_mutex;
         unsigned int count;             /* number of attached slave devices */
         struct device   dev;            /* master device                    */
         struct ccw_device *cdev[0];     /* variable number, allocate as needed */