[PATCH iwl-net 3/3] ice: do not block on the aux device lock in ndo_setup_tc

[Petr Oros]

The TC_SETUP_QDISC_MQPRIO path of ice_setup_tc() takes the auxiliary
device lock to test whether the RDMA driver is bound, and ndo_setup_tc()
runs with the RTNL lock held. This closes the same cycle against the
RDMA auxiliary probe as the two preceding patches.

Use device_trylock() and report the device as busy when it fails, with
a distinct message for the same reason as in the previous patch.

Fixes: 4b31fd4d77ff ("ice: Fix RDMA VSI removal during queue rebuild")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Petr Oros <poros@xxxxxxxxxx>
---
 drivers/net/ethernet/intel/ice/ice_main.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index edb62606d2aae3..7b251136149615 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -9448,7 +9448,11 @@ ice_setup_tc(struct net_device *netdev, enum tc_setup_type type,
 		cdev = pf->cdev_info;
 		if (cdev && cdev->adev) {
 			mutex_lock(&pf->adev_mutex);
-			device_lock(&cdev->adev->dev);
+			if (!device_trylock(&cdev->adev->dev)) {
+				mutex_unlock(&pf->adev_mutex);
+				netdev_dbg(netdev, "RDMA auxiliary device is busy, try again\n");
+				return -EBUSY;
+			}
 			locked = true;
 			if (cdev->adev->dev.driver) {
 				netdev_err(netdev, "Cannot change qdisc when RDMA is active\n");
-- 
2.56.0