[S390] zcrypt: Fix possible dead lock in AP bus module.
If a AP device is unconfigured __ap_poll_all() will call
device_unregister() in software interrupt context which can cause
dead locks. To fix this the device will be only marked as unconfigured
and the device_unregister() call will be done later by either
ap_scan_bus() or ap_queue_message() in process context.
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Ralph Wuerthner <rwuerthn@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index 181b517..a817dad 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -757,10 +757,16 @@
(void *)(unsigned long)qid,
__ap_scan_bus);
rc = ap_query_queue(qid, &queue_depth, &device_type);
- if (dev && rc) {
- put_device(dev);
- device_unregister(dev);
- continue;
+ if (dev) {
+ ap_dev = to_ap_dev(dev);
+ spin_lock_bh(&ap_dev->lock);
+ if (rc || ap_dev->unregistered) {
+ spin_unlock_bh(&ap_dev->lock);
+ put_device(dev);
+ device_unregister(dev);
+ continue;
+ } else
+ spin_unlock_bh(&ap_dev->lock);
}
if (dev) {
put_device(dev);
@@ -994,7 +1000,7 @@
ap_dev->unregistered = 1;
} else {
ap_dev->drv->receive(ap_dev, ap_msg, ERR_PTR(-ENODEV));
- rc = 0;
+ rc = -ENODEV;
}
spin_unlock_bh(&ap_dev->lock);
if (rc == -ENODEV)
@@ -1044,18 +1050,12 @@
*/
static int __ap_poll_all(struct ap_device *ap_dev, unsigned long *flags)
{
- int rc;
-
spin_lock(&ap_dev->lock);
if (!ap_dev->unregistered) {
- rc = ap_poll_queue(ap_dev, flags);
- if (rc)
+ if (ap_poll_queue(ap_dev, flags))
ap_dev->unregistered = 1;
- } else
- rc = 0;
+ }
spin_unlock(&ap_dev->lock);
- if (rc)
- device_unregister(&ap_dev->device);
return 0;
}
