[S390] cio: ensure proper locking during device recognition

Device recognition needs to be started with the ccw device lock
held to prevent race conditions between I/O starting and interrupt
reception.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 7ad6bfb2e55e..afa362ce9e85 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -488,7 +488,9 @@ static int online_store_recog_and_online(struct ccw_device *cdev)
 {
         /* Do device recognition, if needed. */
         if (cdev->private->state == DEV_STATE_BOXED) {
+                spin_lock_irq(cdev->ccwlock);
                 ccw_device_recognition(cdev);
+                spin_unlock_irq(cdev->ccwlock);
                 wait_event(cdev->private->wait_q,
                            cdev->private->flags.recog_done);
                 if (cdev->private->state != DEV_STATE_OFFLINE)