[PATCH 5.15 031/110] ice: Fix error with handling of bonding MTU

Greg Kroah-Hartman
2022-03-14T12:13:01Z

From: Dave Ertman <david.m.ertman@intel.com>

[ Upstream commit 97b0129146b1544bbb0773585327896da3bb4e0a ]

When a bonded interface is destroyed, .ndo_change_mtu can be called
during the tear-down process while the RTNL lock is held. This is a
problem since the auxiliary driver linked to the LAN driver needs to be
notified of the MTU change, and this requires grabbing a device_lock on
the auxiliary_device's dev. Currently this is being attempted in the
same execution context as the call to .ndo_change_mtu which is causing a
dead-lock.

Move the notification of the changed MTU to a separate execution context
(watchdog service task) and eliminate the "before" notification.

Fixes: 348048e724a0e ("ice: Implement iidc operations")
Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
Tested-by: Jonathan Toppins <jtoppins@redhat.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/intel/ice/ice.h | 1 +
drivers/net/ethernet/intel/ice/ice_main.c | 29 +++++++++++------------
2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
index 387322615e08..f23a741e30bf 100644
--- a/drivers/net/ethernet/intel/ice/ice.h
+++ b/drivers/net/ethernet/intel/ice/ice.h
@@ -398,6 +398,7 @@ enum ice_pf_flags {
ICE_FLAG_MDD_AUTO_RESET_VF,
ICE_FLAG_LINK_LENIENT_MODE_ENA,
ICE_FLAG_PLUG_AUX_DEV,
+ ICE_FLAG_MTU_CHANGED,
ICE_PF_FLAGS_NBITS /* must be last */
};

diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index 8a0c928853e6..d6ee62ae4480 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -2146,6 +2146,17 @@ static void ice_service_task(struct work_struct *work)
if (test_and_clear_bit(ICE_FLAG_PLUG_AUX_DEV, pf->flags))
ice_plug_aux_dev(pf);

+ if (test_and_clear_bit(ICE_FLAG_MTU_CHANGED, pf->flags)) {
+ struct iidc_event *event;
+
+ event = kzalloc(sizeof(*event), GFP_KERNEL);
+ if (event) {
+ set_bit(IIDC_EVENT_AFTER_MTU_CHANGE, event->type);
+ ice_send_event_to_aux(pf, event);
+ kfree(event);
+ }
+ }
+
ice_clean_adminq_subtask(pf);
ice_check_media_subtask(pf);
ice_check_for_hang_subtask(pf);
@@ -6532,7 +6543,6 @@ static int ice_change_mtu(struct net_device *netdev, int new_mtu)
struct ice_netdev_priv *np = netdev_priv(netdev);
struct ice_vsi *vsi = np->vsi;
struct ice_pf *pf = vsi->back;
- struct iidc_event *event;
u8 count = 0;
int err = 0;

@@ -6567,14 +6577,6 @@ static int ice_change_mtu(struct net_device *netdev, int new_mtu)
return -EBUSY;
}

- event = kzalloc(sizeof(*event), GFP_KERNEL);
- if (!event)
- return -ENOMEM;
-
- set_bit(IIDC_EVENT_BEFORE_MTU_CHANGE, event->type);
- ice_send_event_to_aux(pf, event);
- clear_bit(IIDC_EVENT_BEFORE_MTU_CHANGE, event->type);
-
netdev->mtu = (unsigned int)new_mtu;

/* if VSI is up, bring it down and then back up */
@@ -6582,21 +6584,18 @@ static int ice_change_mtu(struct net_device *netdev, int new_mtu)
err = ice_down(vsi);
if (err) {
netdev_err(netdev, "change MTU if_down err %d\n", err);
- goto event_after;
+ return err;
}

err = ice_up(vsi);
if (err) {
netdev_err(netdev, "change MTU if_up err %d\n", err);
- goto event_after;
+ return err;
}
}

netdev_dbg(netdev, "changed MTU to %d\n", new_mtu);
-event_after:
- set_bit(IIDC_EVENT_AFTER_MTU_CHANGE, event->type);
- ice_send_event_to_aux(pf, event);
- kfree(event);
+ set_bit(ICE_FLAG_MTU_CHANGED, pf->flags);

return err;
}
--
2.34.1