On 29/03/2017 12:29, Johannes Thumshirn wrote:
On Wed, Mar 29, 2017 at 12:15:44PM +0100, John Garry wrote:
On 29/03/2017 10:41, Johannes Thumshirn wrote:
In the advent of an SAS device unregister we have to wait for all destruct
works to be done to not accidently delay deletion of a SAS rphy or it's
children to the point when we're removing the SCSI or SAS hosts.
Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
---
drivers/scsi/libsas/sas_discover.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
index 60de662..75b18f1 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/drivers/scsi/libsas/sas_discover.c
@@ -382,9 +382,13 @@ void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *dev)
}
if (!test_and_set_bit(SAS_DEV_DESTROY, &dev->state)) {
+ struct sas_discovery *disc = &dev->port->disc;
+ struct sas_work *sw = &disc->disc_work[DISCE_DESTRUCT].work;
+
sas_rphy_unlink(dev->rphy);
list_move_tail(&dev->disco_list_node, &port->destroy_list);
sas_discover_event(dev->port, DISCE_DESTRUCT);
+ flush_work(&sw->work);
I quickly tested plugging out the expander and we never get past this call
to flush - a hang results:
Can you activat lockdep so we can see which lock it is that we're blocking on?
I have it on:
CONFIG_LOCKDEP_SUPPORT=y
CONFIG_LOCKD=y
CONFIG_LOCKD_V4=y
It's most likely in sas_unregister_common_dev() but this function takes two spin
locks, port->dev_list_lock and ha->lock.
We can see from the callstack I provided that we're working in workqueue
scsi_wq_0 and trying to flush that same queue.
Much appreciated,
John
Thanks a lot,
Johannes
