From: Govindarajulu Varadarajan <gvaradar@xxxxxxxxx>
There is a dead lock in usnic ib_register() and netdev_notify() path.
usnic_ib_discover_pf()
| mutex_lock(&usnic_ib_ibdev_list_lock);
| usnic_ib_device_add();
| ib_register_device()
| usnic_ib_query_port()
| mutex_lock(&us_ibdev->usdev_lock);
| ib_get_eth_speed()
| rtnl_lock()
Order of locking: &usnic_ib_ibdev_list_lock -> usdev_lock -> rtnl_lock
rtnl_lock()
| usnic_ib_netdevice_event()
| mutex_lock(&usnic_ib_ibdev_list_lock);
Order of locking: rtnl_lock -> &usnic_ib_ibdev_list_lock
The solution is to not handle usnic_ib_netdevice_event() with the rtnl
lock held.
This commit creates a single threaded workqueue to defer the handling of
netdev/inet events.
Signed-off-by: Govindarajulu Varadarajan <gvaradar@xxxxxxxxx>
Signed-off-by: Parvi Kaustubhi <pkaustub@xxxxxxxxx>
---
drivers/infiniband/hw/usnic/usnic_ib.h | 6 +++
drivers/infiniband/hw/usnic/usnic_ib_main.c | 60 ++++++++++++++++++++++++-----
2 files changed, 56 insertions(+), 10 deletions(-)
diff --git a/drivers/infiniband/hw/usnic/usnic_ib.h b/drivers/infiniband/hw/usnic/usnic_ib.h
index 525bf27..aff4eb4 100644
--- a/drivers/infiniband/hw/usnic/usnic_ib.h
+++ b/drivers/infiniband/hw/usnic/usnic_ib.h
@@ -93,6 +93,12 @@ struct usnic_ib_vf {
struct list_head link;
};
+struct usnic_work {
+ struct work_struct work;
+ unsigned long event;
+ void *ptr;
+};
+
static inline
struct usnic_ib_dev *to_usdev(struct ib_device *ibdev)
{
diff --git a/drivers/infiniband/hw/usnic/usnic_ib_main.c b/drivers/infiniband/hw/usnic/usnic_ib_main.c
index 413fa57..dd28442 100644
--- a/drivers/infiniband/hw/usnic/usnic_ib_main.c
+++ b/drivers/infiniband/hw/usnic/usnic_ib_main.c
@@ -71,6 +71,7 @@ static const char usnic_version[] =
static DEFINE_MUTEX(usnic_ib_ibdev_list_lock);
static LIST_HEAD(usnic_ib_ibdev_list);
+static struct workqueue_struct *usnic_notify_work;
/* Callback dump funcs */
static int usnic_ib_dump_vf_hdr(void *obj, char *buf, int buf_sz)
@@ -212,21 +213,35 @@ static void usnic_ib_handle_usdev_event(struct usnic_ib_dev *us_ibdev,
mutex_unlock(&us_ibdev->usdev_lock);
}
-static int usnic_ib_netdevice_event(struct notifier_block *notifier,
- unsigned long event, void *ptr)
+static void usnic_ib_netdevice_work(struct work_struct *work)
{
+ struct usnic_work *uswork = container_of(work, struct usnic_work, work);
+ struct net_device *netdev = netdev_notifier_info_to_dev(uswork->ptr);
struct usnic_ib_dev *us_ibdev;
- struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
-
mutex_lock(&usnic_ib_ibdev_list_lock);
list_for_each_entry(us_ibdev, &usnic_ib_ibdev_list, ib_dev_link) {
if (us_ibdev->netdev == netdev) {
- usnic_ib_handle_usdev_event(us_ibdev, event);
+ usnic_ib_handle_usdev_event(us_ibdev, uswork->event);
break;
}
}
mutex_unlock(&usnic_ib_ibdev_list_lock);
+ kfree(uswork);
+}
+
+static int usnic_ib_netdevice_event(struct notifier_block *nblock,
+ unsigned long event, void *ptr)
+{
+ struct usnic_work *uswork;
+
+ uswork = kzalloc(sizeof(*uswork), GFP_ATOMIC);
+ if (uswork) {
+ uswork->event = event;
+ uswork->ptr = ptr;
+ INIT_WORK(&uswork->work, usnic_ib_netdevice_work);
+ queue_work(usnic_notify_work, &uswork->work);
+ }
return NOTIFY_DONE;
}
@@ -276,24 +291,42 @@ static int usnic_ib_handle_inet_event(struct usnic_ib_dev *us_ibdev,
return NOTIFY_DONE;
}
-static int usnic_ib_inetaddr_event(struct notifier_block *notifier,
- unsigned long event, void *ptr)
+static void usnic_ib_inetaddr_work(struct work_struct *work)
{
+ struct usnic_work *uswork = container_of(work, struct usnic_work, work);
struct usnic_ib_dev *us_ibdev;
- struct in_ifaddr *ifa = ptr;
+ struct in_ifaddr *ifa = uswork->ptr;
struct net_device *netdev = ifa->ifa_dev->dev;
mutex_lock(&usnic_ib_ibdev_list_lock);
list_for_each_entry(us_ibdev, &usnic_ib_ibdev_list, ib_dev_link) {
if (us_ibdev->netdev == netdev) {
- usnic_ib_handle_inet_event(us_ibdev, event, ptr);
+ usnic_ib_handle_inet_event(us_ibdev, uswork->event,
+ uswork->ptr);
break;
}
}
mutex_unlock(&usnic_ib_ibdev_list_lock);
+ kfree(uswork);
+}
+
+static int usnic_ib_inetaddr_event(struct notifier_block *nblock,
+ unsigned long event, void *ptr)
+{
+ struct usnic_work *uswork;
+
+ uswork = kzalloc(sizeof(*uswork), GFP_ATOMIC);
+
+ if (uswork) {
+ uswork->ptr = ptr;
+ uswork->event = event;
+ INIT_WORK(&uswork->work, usnic_ib_inetaddr_work);
+ queue_work(usnic_notify_work, &uswork->work);
+ }
return NOTIFY_DONE;
}
+
static struct notifier_block usnic_ib_inetaddr_notifier = {
.notifier_call = usnic_ib_inetaddr_event
};
@@ -653,10 +686,15 @@ static int __init usnic_ib_init(void)
return err;
}
+ usnic_notify_work = create_singlethread_workqueue("usnic_notify_work");
+ if (!usnic_notify_work) {
+ usnic_err("Failed to create notify workqueue");
+ goto out_umem_fini;
+ }
err = pci_register_driver(&usnic_ib_pci_driver);
if (err) {
usnic_err("Unable to register with PCI\n");
- goto out_umem_fini;
+ goto out_notify_work;
}
err = register_netdevice_notifier(&usnic_ib_netdevice_notifier);
@@ -687,6 +725,8 @@ static int __init usnic_ib_init(void)
unregister_netdevice_notifier(&usnic_ib_netdevice_notifier);
out_pci_unreg:
pci_unregister_driver(&usnic_ib_pci_driver);
+out_notify_work:
+ destroy_workqueue(usnic_notify_work);
out_umem_fini:
usnic_uiom_fini();
--
2.7.0
