[Intel-wired-lan] [PATCH iwl-net v3 4/6] ice: check ICE_VSI_DOWN under rtnl_lock when preparing for reset

[Larysa Zaremba]

Consider the following scenario:

.ndo_bpf()              | ice_prepare_for_reset()               |
________________________|_______________________________________|
rtnl_lock()             |                                       |
ice_down()              |                                       |
                        | test_bit(ICE_VSI_DOWN) - true         |
                        | ice_dis_vsi() returns                 |
ice_up()                |                                       |
                        | proceeds to rebuild a running VSI     |

.ndo_bpf() is not the only rtnl-locked callback that toggles the interface
to apply new configuration. Another example is .set_channels().

To avoid the race condition above, act only after reading ICE_VSI_DOWN
under rtnl_lock.

Fixes: 0f9d5027a749 ("ice: Refactor VSI allocation, deletion and rebuild flow")
Reviewed-by: Wojciech Drewek <wojciech.dre...@intel.com>
Reviewed-by: Jacob Keller <jacob.e.kel...@intel.com>
Tested-by: Chandan Kumar Rout <chandanx.r...@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zare...@intel.com>
---
 drivers/net/ethernet/intel/ice/ice_lib.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c 
b/drivers/net/ethernet/intel/ice/ice_lib.c
index b72338974a60..94029e446b99 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -2665,8 +2665,7 @@ int ice_ena_vsi(struct ice_vsi *vsi, bool locked)
  */
 void ice_dis_vsi(struct ice_vsi *vsi, bool locked)
 {
-       if (test_bit(ICE_VSI_DOWN, vsi->state))
-               return;
+       bool already_down = test_bit(ICE_VSI_DOWN, vsi->state);
 
        set_bit(ICE_VSI_NEEDS_RESTART, vsi->state);
 
@@ -2674,15 +2673,16 @@ void ice_dis_vsi(struct ice_vsi *vsi, bool locked)
                if (netif_running(vsi->netdev)) {
                        if (!locked)
                                rtnl_lock();
-
-                       ice_vsi_close(vsi);
+                       already_down = test_bit(ICE_VSI_DOWN, vsi->state);
+                       if (!already_down)
+                               ice_vsi_close(vsi);
 
                        if (!locked)
                                rtnl_unlock();
-               } else {
+               } else if (!already_down) {
                        ice_vsi_close(vsi);
                }
-       } else if (vsi->type == ICE_VSI_CTRL) {
+       } else if (vsi->type == ICE_VSI_CTRL && !already_down) {
                ice_vsi_close(vsi);
        }
 }
-- 
2.43.0