s390/cio: use device_lock to synchronize calls to the ccw driver

When calling set_{on,off}line of a ccw device driver we hold the
module reference of the owner. This is pretty useless - we don't
want to prevent module unloading but driver unbinding. Use the
driver core's device_lock instead.

Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 6 insertions, 10 deletions

diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 4a0734fcc83c..e9d783563cbb 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -549,17 +549,12 @@ static ssize_t online_store (struct device *dev, struct device_attribute *attr,
         if (!dev_fsm_final_state(cdev) &&
             cdev->private->state != DEV_STATE_DISCONNECTED) {
                 ret = -EAGAIN;
-                goto out_onoff;
+                goto out;
         }
         /* Prevent conflict between pending work and on-/offline processing.*/
         if (work_pending(&cdev->private->todo_work)) {
                 ret = -EAGAIN;
-                goto out_onoff;
-        }
-
-        if (cdev->drv && !try_module_get(cdev->drv->driver.owner)) {
-                ret = -EINVAL;
-                goto out_onoff;
+                goto out;
         }
         if (!strncmp(buf, "force\n", count)) {
                 force = 1;
@@ -571,6 +566,8 @@ static ssize_t online_store (struct device *dev, struct device_attribute *attr,
         }
         if (ret)
                 goto out;
+
+        device_lock(dev);
         switch (i) {
         case 0:
                 ret = online_store_handle_offline(cdev);
@@ -581,10 +578,9 @@ static ssize_t online_store (struct device *dev, struct device_attribute *attr,
         default:
                 ret = -EINVAL;
         }
+        device_unlock(dev);
+
 out:
-        if (cdev->drv)
-                module_put(cdev->drv->driver.owner);
-out_onoff:
         atomic_set(&cdev->private->onoff, 0);
         return (ret < 0) ? ret : count;
 }