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[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>
This commit is contained in:
Ralph Wuerthner 2007-03-26 20:42:42 +02:00 committed by Heiko Carstens
parent 25c61a1fe8
commit c6a4826473
1 changed files with 13 additions and 13 deletions
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26
drivers/s390/crypto/ap_bus.c
View File

@ -757,10 +757,16 @@ static void ap_scan_bus(struct work_struct *unused)
(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 @@ void ap_queue_message(struct ap_device *ap_dev, struct ap_message *ap_msg)
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 void ap_poll_timeout(unsigned long unused)
*/
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;
}