[PATCH net-next v2 10/11] scsi: fcoe: don't recurse on the netdev's ops lock

[Jakub Kicinski <kuba@kernel.org>]

fcoe_link_speed_update() calls __ethtool_get_link_ksettings() on the
lport's netdev, which will soon take the dev's ops lock. Some notifier
callers already arrive with this lock held. Switch to
netif_get_link_ksettings() and adjust the explicit call sites to take
the netdev lock explicitly.

Within fcoe_device_notification() try to only query the link speed
from notifiers which announce link state change (UP / CHANGE),
DOWN / GOING_DOWN notifiers are slightly sketchy when it comes
to ops locking right now, and the code already special-cases
those by maintaining the local link_possible variable.

Also take the lock in bnx2fc_net_config(), even though I think
that bnx2fc call sites are largely irrelevant since it's not
an ops-locked driver.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/scsi/bnx2fc/bnx2fc_fcoe.c  | 3 +++
 drivers/scsi/fcoe/fcoe.c           | 6 ++++--
 drivers/scsi/fcoe/fcoe_transport.c | 4 +++-
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
index 26e0ff380860..c95b084cad69 100644
--- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
+++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
@@ -17,6 +17,7 @@
 #include "bnx2fc.h"
 
 #include <linux/ethtool.h>
+#include <net/netdev_lock.h>
 
 static struct list_head adapter_list;
 static struct list_head if_list;
@@ -815,7 +816,9 @@ static int bnx2fc_net_config(struct fc_lport *lport, struct net_device *netdev)
 	port->fcoe_pending_queue_active = 0;
 	timer_setup(&port->timer, fcoe_queue_timer, 0);
 
+	netdev_lock_ops(netdev);
 	fcoe_link_speed_update(lport);
+	netdev_unlock_ops(netdev);
 
 	if (!lport->vport) {
 		if (fcoe_get_wwn(netdev, &wwnn, NETDEV_FCOE_WWNN))
diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c
index 534596c6d76c..438ac7c3a9e3 100644
--- a/drivers/scsi/fcoe/fcoe.c
+++ b/drivers/scsi/fcoe/fcoe.c
@@ -25,6 +25,7 @@
 #include <scsi/scsicam.h>
 #include <scsi/scsi_transport.h>
 #include <scsi/scsi_transport_fc.h>
+#include <net/netdev_lock.h>
 #include <net/rtnetlink.h>
 
 #include <scsi/fc/fc_encaps.h>
@@ -737,7 +738,9 @@ static int fcoe_netdev_config(struct fc_lport *lport, struct net_device *netdev)
 	port->fcoe_pending_queue_active = 0;
 	timer_setup(&port->timer, fcoe_queue_timer, 0);
 
+	netdev_lock_ops(netdev);
 	fcoe_link_speed_update(lport);
+	netdev_unlock_ops(netdev);
 
 	if (!lport->vport) {
 		if (fcoe_get_wwn(netdev, &wwnn, NETDEV_FCOE_WWNN))
@@ -1841,6 +1844,7 @@ static int fcoe_device_notification(struct notifier_block *notifier,
 		break;
 	case NETDEV_UP:
 	case NETDEV_CHANGE:
+		fcoe_link_speed_update(lport);
 		break;
 	case NETDEV_CHANGEMTU:
 		if (netdev->fcoe_mtu)
@@ -1871,8 +1875,6 @@ static int fcoe_device_notification(struct notifier_block *notifier,
 				"from netdev netlink\n", event);
 	}
 
-	fcoe_link_speed_update(lport);
-
 	cdev = fcoe_ctlr_to_ctlr_dev(ctlr);
 
 	if (link_possible && !fcoe_link_ok(lport)) {
diff --git a/drivers/scsi/fcoe/fcoe_transport.c b/drivers/scsi/fcoe/fcoe_transport.c
index 88d85fc9a52a..2bbb9a38e61d 100644
--- a/drivers/scsi/fcoe/fcoe_transport.c
+++ b/drivers/scsi/fcoe/fcoe_transport.c
@@ -111,6 +111,8 @@ static inline u32 eth2fc_speed(u32 eth_port_speed)
  * fcoe_link_speed_update() - Update the supported and actual link speeds
  * @lport: The local port to update speeds for
  *
+ * Caller must hold the netdev's ops lock.
+ *
  * Returns: 0 if the ethtool query was successful
  *          -1 if the ethtool query failed
  */
@@ -119,7 +121,7 @@ int fcoe_link_speed_update(struct fc_lport *lport)
 	struct net_device *netdev = fcoe_get_netdev(lport);
 	struct ethtool_link_ksettings ecmd;
 
-	if (!__ethtool_get_link_ksettings(netdev, &ecmd)) {
+	if (!netif_get_link_ksettings(netdev, &ecmd)) {
 		lport->link_supported_speeds &= ~(FC_PORTSPEED_1GBIT  |
 		                                  FC_PORTSPEED_10GBIT |
 		                                  FC_PORTSPEED_20GBIT |
-- 
2.54.0