sfc: hold filter_sem consistently during reset

We should take and release the filter_sem consistently during the
reset process, in the same manner as the mac_lock and reset_lock.

For lockdep consistency we also take the filter_sem for write around
other calls to efx->type->init().

Fixes: c2bebe37c6b6 ("sfc: give ef10 its own rwsem in the filter table instead of filter_lock")
Signed-off-by: Bert Kenward <bkenward@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/efx.c

@@ -1871,12 +1871,6 @@ static void efx_remove_filters(struct efx_nic *efx)
 	up_write(&efx->filter_sem);
 }
 
-static void efx_restore_filters(struct efx_nic *efx)
-{
-	down_read(&efx->filter_sem);
-	efx->type->filter_table_restore(efx);
-	up_read(&efx->filter_sem);
-}
 
 /**************************************************************************
  *
@@ -2688,6 +2682,7 @@ void efx_reset_down(struct efx_nic *efx, enum reset_type method)
 	efx_disable_interrupts(efx);
 
 	mutex_lock(&efx->mac_lock);
+	down_write(&efx->filter_sem);
 	mutex_lock(&efx->rss_lock);
 	if (efx->port_initialized && method != RESET_TYPE_INVISIBLE &&
 	    method != RESET_TYPE_DATAPATH)
@@ -2745,9 +2740,8 @@ int efx_reset_up(struct efx_nic *efx, enum reset_type method, bool ok)
 	if (efx->type->rx_restore_rss_contexts)
 		efx->type->rx_restore_rss_contexts(efx);
 	mutex_unlock(&efx->rss_lock);
-	down_read(&efx->filter_sem);
-	efx_restore_filters(efx);
-	up_read(&efx->filter_sem);
+	efx->type->filter_table_restore(efx);
+	up_write(&efx->filter_sem);
 	if (efx->type->sriov_reset)
 		efx->type->sriov_reset(efx);
 
@@ -2764,6 +2758,7 @@ fail:
 	efx->port_initialized = false;
 
 	mutex_unlock(&efx->rss_lock);
+	up_write(&efx->filter_sem);
 	mutex_unlock(&efx->mac_lock);
 
 	return rc;
@@ -3473,7 +3468,9 @@ static int efx_pci_probe_main(struct efx_nic *efx)
 
 	efx_init_napi(efx);
 
+	down_write(&efx->filter_sem);
 	rc = efx->type->init(efx);
+	up_write(&efx->filter_sem);
 	if (rc) {
 		netif_err(efx, probe, efx->net_dev,
 			  "failed to initialise NIC\n");
@@ -3765,7 +3762,9 @@ static int efx_pm_resume(struct device *dev)
 	rc = efx->type->reset(efx, RESET_TYPE_ALL);
 	if (rc)
 		return rc;
+	down_write(&efx->filter_sem);
 	rc = efx->type->init(efx);
+	up_write(&efx->filter_sem);
 	if (rc)
 		return rc;
 	rc = efx_pm_thaw(dev);