[S390] dasd: fix refcounting in dasd_change_state
To set a dasd online dasd_change_state is called twice. The first
cycle will schedule initial analysis of the device, set the rc to
-EAGAIN and will not touch the device state any more.
The initial analysis will in turn call dasd_change_state to increase
the state to the final DASD_STATE_ONLINE.
If the dasd_change_state on the second thread outruns the other one
both finish with the state set to DASD_STATE_ONLINE and the device
refcount will be decreased by 2.
Fix this by leaving dasd_change_state on rc == -EAGAIN so that the
refcount will always be decreased by 1.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.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 99e7153..7498366 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -470,7 +470,7 @@
*/
static void dasd_change_state(struct dasd_device *device)
{
- int rc;
+ int rc;
if (device->state == device->target)
/* Already where we want to go today... */
@@ -479,8 +479,10 @@
rc = dasd_increase_state(device);
else
rc = dasd_decrease_state(device);
- if (rc && rc != -EAGAIN)
- device->target = device->state;
+ if (rc == -EAGAIN)
+ return;
+ if (rc)
+ device->target = device->state;
if (device->state == device->target) {
wake_up(&dasd_init_waitq);