[S390] cio: call ccw driver notify function with lock held
Calling a ccw driver's notify function without the ccw device lock
held opens up a race window between discovery and handling of a change
in the device operational state. As a result, the device driver may
encounter unexpected device malfunction, leading to out-of-retry
situations or similar.
Remove race by extending the ccw device lock from state change
discovery to the calling of the notify function.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 1b6c52e..acb7801 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2333,13 +2333,11 @@
{
struct dasd_device *device;
struct dasd_ccw_req *cqr;
- unsigned long flags;
int ret;
- device = dasd_device_from_cdev(cdev);
+ device = dasd_device_from_cdev_locked(cdev);
if (IS_ERR(device))
return 0;
- spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
ret = 0;
switch (event) {
case CIO_GONE:
@@ -2369,7 +2367,6 @@
ret = 1;
break;
}
- spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
dasd_put_device(device);
return ret;
}