ice: synchronize_rcu() when terminating rings

Unfortunately, the ice driver doesn't respect the RCU critical section that
XSK wakeup is surrounded with. To fix this, add synchronize_rcu() calls to
paths that destroy resources that might be in use.

This was addressed in other AF_XDP ZC enabled drivers, for reference see
for example commit b3873a5be757 ("net/i40e: Fix concurrency issues
between config flow and XSK")

Fixes: efc2214b6047 ("ice: Add support for XDP")
Fixes: 2d4238f55697 ("ice: Add support for AF_XDP")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: Shwetha Nagaraju <shwetha.nagaraju@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
index 26eaee0..8ed3c9a 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice.h
+++ b/drivers/net/ethernet/intel/ice/ice.h
@@ -671,7 +671,7 @@ static inline struct ice_pf *ice_netdev_to_pf(struct net_device *netdev)
 
 static inline bool ice_is_xdp_ena_vsi(struct ice_vsi *vsi)
 {
-       return !!vsi->xdp_prog;
+       return !!READ_ONCE(vsi->xdp_prog);
 }
 
 static inline void ice_set_ring_xdp(struct ice_tx_ring *ring)

diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index 1d2ca39..d2039a9 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -2758,8 +2758,10 @@ free_qmap:
 
        ice_for_each_xdp_txq(vsi, i)
                if (vsi->xdp_rings[i]) {
-                       if (vsi->xdp_rings[i]->desc)
+                       if (vsi->xdp_rings[i]->desc) {
+                               synchronize_rcu();
                                ice_free_tx_ring(vsi->xdp_rings[i]);
+                       }
                        kfree_rcu(vsi->xdp_rings[i], rcu);
                        vsi->xdp_rings[i] = NULL;
                }

diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
index dfbcaf0..33b28a7 100644 (file)
--- a/drivers/net/ethernet/intel/ice/ice_xsk.c
+++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
@@ -41,8 +41,10 @@ static void ice_qp_reset_stats(struct ice_vsi *vsi, u16 q_idx)
 static void ice_qp_clean_rings(struct ice_vsi *vsi, u16 q_idx)
 {
        ice_clean_tx_ring(vsi->tx_rings[q_idx]);
-       if (ice_is_xdp_ena_vsi(vsi))
+       if (ice_is_xdp_ena_vsi(vsi)) {
+               synchronize_rcu();
                ice_clean_tx_ring(vsi->xdp_rings[q_idx]);
+       }
        ice_clean_rx_ring(vsi->rx_rings[q_idx]);
 }