[PATCH iwl-next v2] ixgbe: remove ixgbe_ping_all_vfs() from link state change handlers

[Aleksandr Loktionov <aleksandr.loktionov@intel.com>]

When multiple VFs are brought up simultaneously, a VF can receive a CTS
(Clear To Send) mailbox message instead of the expected RESET | (N)ACK
response, because the watchdog fires a gratuitous ping right as the VF
mailbox transaction is in progress.

Remove the ixgbe_ping_all_vfs() call from both ixgbe_watchdog_link_is_up()
and ixgbe_watchdog_link_is_down().  Both paths contain an identical call
with the same race window during VF initialization: link-state changes
(up or down) can arrive while VFs are mid-initialization, and the
gratuitous ping from either direction collides with the VF mailbox state
machine for the same reason.

Link-state changes are already communicated to VFs through the normal
mailbox protocol; these extra pings are redundant on both paths.

This removes the last two callers of ixgbe_ping_all_vfs(), so remove
the now-unused function and its declaration as well.

Suggested-by: Sebastian Basierski <sebastianx.basierski@intel.com>
Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
---
v1 -> v2: no code changes, resending to pick up Reviewed-by
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c  |  6 ------
 drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c | 14 --------------
 drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.h |  1 -
 3 files changed, 21 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index f918564..365acf8 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -8181,9 +8181,6 @@ static void ixgbe_watchdog_link_is_up(struct ixgbe_adapter *adapter)
 
 	/* update the default user priority for VFs */
 	ixgbe_update_default_up(adapter);
-
-	/* ping all the active vfs to let them know link has changed */
-	ixgbe_ping_all_vfs(adapter);
 }
 
 /**
@@ -8214,9 +8211,6 @@ static void ixgbe_watchdog_link_is_down(struct ixgbe_adapter *adapter)
 
 	e_info(drv, "NIC Link is Down\n");
 	netif_carrier_off(netdev);
-
-	/* ping all the active vfs to let them know link has changed */
-	ixgbe_ping_all_vfs(adapter);
 }
 
 static bool ixgbe_ring_tx_pending(struct ixgbe_adapter *adapter)
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
index 431d77d..da641e9 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
@@ -1515,20 +1515,6 @@ static inline void ixgbe_ping_vf(struct ixgbe_adapter *adapter, int vf)
 	ixgbe_write_mbx(hw, &ping, 1, vf);
 }
 
-void ixgbe_ping_all_vfs(struct ixgbe_adapter *adapter)
-{
-	struct ixgbe_hw *hw = &adapter->hw;
-	u32 ping;
-	int i;
-
-	for (i = 0 ; i < adapter->num_vfs; i++) {
-		ping = IXGBE_PF_CONTROL_MSG;
-		if (adapter->vfinfo[i].clear_to_send)
-			ping |= IXGBE_VT_MSGTYPE_CTS;
-		ixgbe_write_mbx(hw, &ping, 1, i);
-	}
-}
-
 /**
  * ixgbe_set_all_vfs - update vfs queues
  * @adapter: Pointer to adapter struct
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.h
index bc4cab9..f755bfd 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.h
@@ -18,7 +18,6 @@ void ixgbe_restore_vf_multicasts(struct ixgbe_adapter *adapter);
 bool ixgbe_check_mdd_event(struct ixgbe_adapter *adapter);
 void ixgbe_msg_task(struct ixgbe_adapter *adapter);
 int ixgbe_vf_configuration(struct pci_dev *pdev, unsigned int event_mask);
-void ixgbe_ping_all_vfs(struct ixgbe_adapter *adapter);
 void ixgbe_set_all_vfs(struct ixgbe_adapter *adapter);
 int ixgbe_ndo_set_vf_mac(struct net_device *netdev, int queue, u8 *mac);
 int ixgbe_ndo_set_vf_vlan(struct net_device *netdev, int queue, u16 vlan,
-- 
2.52.0