s390/zcrypt: ap bus rescan problem when toggle crypto adapters on/off

The bus rescan process was called simultaneously on
every device failure. This finally leads into race
conditions (double device add/remove actions).

This patch protects the rescan area by mutual exclusion
and improves ap_config_timer handling

Signed-off-by: Ingo Tuchscherer <ingo.tuchscherer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Ingo Tuchscherer 2013-04-12 17:52:08 +02:00 committed by Martin Schwidefsky
parent 1553556067
commit 56bbe68669

View file

@ -954,15 +954,11 @@ EXPORT_SYMBOL(ap_driver_unregister);
void ap_bus_force_rescan(void)
{
/* Delete the AP bus rescan timer. */
del_timer(&ap_config_timer);
/* processing a synchonuous bus rescan */
ap_scan_bus(NULL);
/* Setup the AP bus rescan timer again. */
ap_config_timer.expires = jiffies + ap_config_time * HZ;
add_timer(&ap_config_timer);
/* reconfigure the AP bus rescan timer. */
mod_timer(&ap_config_timer, jiffies + ap_config_time * HZ);
/* processing a asynchronous bus rescan */
queue_work(ap_work_queue, &ap_config_work);
flush_work(&ap_config_work);
}
EXPORT_SYMBOL(ap_bus_force_rescan);
@ -1305,8 +1301,9 @@ static void ap_scan_bus(struct work_struct *unused)
int rc, i;
ap_query_configuration();
if (ap_select_domain() != 0)
if (ap_select_domain() != 0) {
return;
}
for (i = 0; i < AP_DEVICES; i++) {
qid = AP_MKQID(i, ap_domain_index);
dev = bus_find_device(&ap_bus_type, NULL,