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Commit 589c74d5 authored by Stefan Haberland's avatar Stefan Haberland Committed by Martin Schwidefsky
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[S390] dasd: fix refcounting. 



The function dasd_device_from_cdev returns a reference to the dasd
device and increases the refcount by one. If an exception occurs,
the refcount was not decreased in all cases
e.g. in dasd_discipline_show.
Prevent the offline processing from hang by correcting two functions
to decrease the refcount even if an error occured.

Signed-off-by: default avatarStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 9eb25122

drivers/s390/block/dasd.c

+15 −9
Original line number Diff line number Diff line
@@ -1003,12 +1003,20 @@ static void dasd_handle_killed_request(struct ccw_device *cdev, 
		return;

	}



	device = (struct dasd_device *) cqr->startdev;

	if (device == NULL ||

	    device != dasd_device_from_cdev_locked(cdev) ||

	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {

	device = dasd_device_from_cdev_locked(cdev);

	if (IS_ERR(device)) {

		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",

				"unable to get device from cdev");

		return;

	}



	if (!cqr->startdev ||

	    device != cqr->startdev ||

	    strncmp(cqr->startdev->discipline->ebcname,

		    (char *) &cqr->magic, 4)) {

		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",

				"invalid device in request");

		dasd_put_device(device);

		return;

	}
@@ -2291,11 +2299,6 @@ static void dasd_generic_auto_online(void *data, async_cookie_t cookie) 
	if (ret)

		pr_warning("%s: Setting the DASD online failed with rc=%d\n",

			   dev_name(&cdev->dev), ret);

	else {

		struct dasd_device *device = dasd_device_from_cdev(cdev);

		wait_event(dasd_init_waitq, _wait_for_device(device));

		dasd_put_device(device);

	}

}



/*
@@ -2430,6 +2433,9 @@ int dasd_generic_set_online(struct ccw_device *cdev, 
	} else

		pr_debug("dasd_generic device %s found\n",

				dev_name(&cdev->dev));



	wait_event(dasd_init_waitq, _wait_for_device(device));



	dasd_put_device(device);

	return rc;

}

drivers/s390/block/dasd_devmap.c

+10 −3
Original line number Diff line number Diff line
@@ -874,11 +874,18 @@ dasd_discipline_show(struct device *dev, struct device_attribute *attr, 
	ssize_t len;



	device = dasd_device_from_cdev(to_ccwdev(dev));

	if (!IS_ERR(device) && device->discipline) {

	if (IS_ERR(device))

		goto out;

	else if (!device->discipline) {

		dasd_put_device(device);

		goto out;

	} else {

		len = snprintf(buf, PAGE_SIZE, "%s\n",

			       device->discipline->name);

		dasd_put_device(device);

	} else

		return len;

	}

out:

	len = snprintf(buf, PAGE_SIZE, "none\n");

	return len;

}