s390/dasd: fix hanging DASD driver unbind

BugLink: https://bugs.launchpad.net/bugs/1919492
commit 7d365bd0bff3c0310c39ebaffc9a8458e036d666 upstream.

In case of an unbind of the DASD device driver the function
dasd_generic_remove() is called which shuts down the device.
Among others this functions removes the int_handler from the cdev.
During shutdown the device cancels all outstanding IO requests and waits
for completion of the clear request.
Unfortunately the clear interrupt will never be received when there is no
interrupt handler connected.

Fix by moving the int_handler removal after the call to the state machine
where no request or interrupt is outstanding.

Cc: stable@vger.kernel.org
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Tested-by: Bjoern Walk <bwalk@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index c7eb9a10c680d2ba4782d5372c7fe577975d0ff3..86ca2d5fc4216f6d5dbd921c5e81e4275bdc98f0 100644 (file)
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -3503,8 +3503,6 @@ void dasd_generic_remove(struct ccw_device *cdev)
        struct dasd_device *device;
        struct dasd_block *block;
 
-       cdev->handler = NULL;
-
        device = dasd_device_from_cdev(cdev);
        if (IS_ERR(device)) {
                dasd_remove_sysfs_files(cdev);
@@ -3523,6 +3521,7 @@ void dasd_generic_remove(struct ccw_device *cdev)
         * no quite down yet.
         */
        dasd_set_target_state(device, DASD_STATE_NEW);
+       cdev->handler = NULL;
        /* dasd_delete_device destroys the device reference. */
        block = device->block;
        dasd_delete_device(device);