sfc: Use netif_device_{detach,attach}() around reset and self-test

We need to keep the TX queues stopped throughout a reset, without
triggering the TX watchdog and regardless of the link state.  The
proper way to do this is to use netif_device_{detach,attach}() just as
we do around suspend/resume, rather than the current bodge of faking
link-down.

Since we also need to do this during an offline self-test and we
perform a reset during that, add these function calls outside of
efx_reset_down() and efx_reset_up().

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

4 files changed, 14 insertions, 19 deletions

diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index 796c47e03f65..05502b359b9e 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -798,11 +798,6 @@ void efx_link_status_changed(struct efx_nic *efx)
         if (!netif_running(efx->net_dev))
                 return;
 
-        if (efx->port_inhibited) {
-                netif_carrier_off(efx->net_dev);
-                return;
-        }
-
         if (link_state->up != netif_carrier_ok(efx->net_dev)) {
                 efx->n_link_state_changes++;
 
@@ -1450,7 +1445,7 @@ static void efx_start_all(struct efx_nic *efx)
          * restart the transmit interface early so the watchdog timer stops */
         efx_start_port(efx);
 
-        if (efx_dev_registered(efx) && !efx->port_inhibited)
+        if (efx_dev_registered(efx) && netif_device_present(efx->net_dev))
                 netif_tx_wake_all_queues(efx->net_dev);
 
         efx_for_each_channel(channel, efx)
@@ -2114,6 +2109,7 @@ int efx_reset(struct efx_nic *efx, enum reset_type method)
         netif_info(efx, drv, efx->net_dev, "resetting (%s)\n",
                    RESET_TYPE(method));
 
+        netif_device_detach(efx->net_dev);
         efx_reset_down(efx, method);
 
         rc = efx->type->reset(efx, method);
@@ -2147,6 +2143,7 @@ out:
                 efx->state = STATE_DISABLED;
         } else {
                 netif_dbg(efx, drv, efx->net_dev, "reset complete\n");
+                netif_device_attach(efx->net_dev);
         }
         return rc;
 }
diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index 5718260298c4..ce9697bac1b9 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -670,13 +670,12 @@ struct efx_filter_state;
  * @mtd_list: List of MTDs attached to the NIC
  * @nic_data: Hardware dependent state
  * @mac_lock: MAC access lock. Protects @port_enabled, @phy_mode,
- *      @port_inhibited, efx_monitor() and efx_reconfigure_port()
+ *      efx_monitor() and efx_reconfigure_port()
  * @port_enabled: Port enabled indicator.
  *      Serialises efx_stop_all(), efx_start_all(), efx_monitor() and
  *      efx_mac_work() with kernel interfaces. Safe to read under any
  *      one of the rtnl_lock, mac_lock, or netif_tx_lock, but all three must
  *      be held to modify it.
- * @port_inhibited: If set, the netif_carrier is always off. Hold the mac_lock
  * @port_initialized: Port initialized?
  * @net_dev: Operating system network device. Consider holding the rtnl lock
  * @stats_buffer: DMA buffer for statistics
@@ -764,7 +763,6 @@ struct efx_nic {
         struct mutex mac_lock;
         struct work_struct mac_work;
         bool port_enabled;
-        bool port_inhibited;
 
         bool port_initialized;
         struct net_device *net_dev;
diff --git a/drivers/net/sfc/selftest.c b/drivers/net/sfc/selftest.c
index 50ad3bcaf68a..822f6c2a6a7c 100644
--- a/drivers/net/sfc/selftest.c
+++ b/drivers/net/sfc/selftest.c
@@ -695,12 +695,12 @@ int efx_selftest(struct efx_nic *efx, struct efx_self_tests *tests,
         /* Offline (i.e. disruptive) testing
          * This checks MAC and PHY loopback on the specified port. */
 
-        /* force the carrier state off so the kernel doesn't transmit during
-         * the loopback test, and the watchdog timeout doesn't fire. Also put
-         * falcon into loopback for the register test.
+        /* Detach the device so the kernel doesn't transmit during the
+         * loopback test and the watchdog timeout doesn't fire.
          */
+        netif_device_detach(efx->net_dev);
+
         mutex_lock(&efx->mac_lock);
-        efx->port_inhibited = true;
         if (efx->loopback_modes) {
                 /* We need the 312 clock from the PHY to test the XMAC
                  * registers, so move into XGMII loopback if available */
@@ -750,12 +750,11 @@ int efx_selftest(struct efx_nic *efx, struct efx_self_tests *tests,
         /* restore the PHY to the previous state */
         mutex_lock(&efx->mac_lock);
         efx->phy_mode = phy_mode;
-        efx->port_inhibited = false;
         efx->loopback_mode = loopback_mode;
         __efx_reconfigure_port(efx);
         mutex_unlock(&efx->mac_lock);
 
-        netif_tx_wake_all_queues(efx->net_dev);
+        netif_device_attach(efx->net_dev);
 
         return rc_test;
 }
diff --git a/drivers/net/sfc/tx.c b/drivers/net/sfc/tx.c
index d2c85dfdf3bf..84eb99e0f8d2 100644
--- a/drivers/net/sfc/tx.c
+++ b/drivers/net/sfc/tx.c
@@ -205,7 +205,9 @@ netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb)
                                         goto unwind;
                                 }
                                 smp_mb();
-                                netif_tx_start_queue(tx_queue->core_txq);
+                                if (likely(!efx->loopback_selftest))
+                                        netif_tx_start_queue(
+                                                tx_queue->core_txq);
                         }
 
                         insert_ptr = tx_queue->insert_count & tx_queue->ptr_mask;
@@ -338,8 +340,7 @@ netdev_tx_t efx_hard_start_xmit(struct sk_buff *skb,
         struct efx_tx_queue *tx_queue;
         unsigned index, type;
 
-        if (unlikely(efx->port_inhibited))
-                return NETDEV_TX_BUSY;
+        EFX_WARN_ON_PARANOID(!netif_device_present(net_dev));
 
         index = skb_get_queue_mapping(skb);
         type = skb->ip_summed == CHECKSUM_PARTIAL ? EFX_TXQ_TYPE_OFFLOAD : 0;
@@ -436,7 +437,7 @@ void efx_xmit_done(struct efx_tx_queue *tx_queue, unsigned int index)
         smp_mb();
         if (unlikely(netif_tx_queue_stopped(tx_queue->core_txq)) &&
             likely(efx->port_enabled) &&
-            likely(!efx->port_inhibited)) {
+            likely(netif_device_present(efx->net_dev))) {
                 fill_level = tx_queue->insert_count - tx_queue->read_count;
                 if (fill_level < EFX_TXQ_THRESHOLD(efx)) {
                         EFX_BUG_ON_PARANOID(!efx_dev_registered(efx));