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authorRalph Wuerthner <rwuerthn@de.ibm.com>2007-03-26 20:42:42 +0200
committerHeiko Carstens <heiko.carstens@de.ibm.com>2007-03-26 20:43:47 +0200
commitc6a48264739e3486f66e5b21a543c9573b713621 (patch)
treea25c70053be8fa8e3a97f7b0bf377f37fa98e31f
parent25c61a1fe8c97d1352a2dc0eda25128b3be0db27 (diff)
[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>
-rw-r--r--drivers/s390/crypto/ap_bus.c26
1 files changed, 13 insertions, 13 deletions
diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index 181b51772b1..a817dade37c 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -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;
}