sfc: lock TX queues when calling netif_device_detach()

The assertion of netif_device_present() at the top of
efx_hard_start_xmit() may fail if we don't do this.

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

3 files changed, 16 insertions, 3 deletions

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 4f86d0cd516a..6f073d014ad3 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -2279,7 +2279,7 @@ 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_device_detach_sync(efx);
         efx_reset_down(efx, method);
 
         rc = efx->type->reset(efx, method);
@@ -2758,7 +2758,7 @@ static int efx_pm_freeze(struct device *dev)
         if (efx->state != STATE_DISABLED) {
                 efx->state = STATE_UNINIT;
 
-                netif_device_detach(efx->net_dev);
+                efx_device_detach_sync(efx);
 
                 efx_stop_all(efx);
                 efx_stop_interrupts(efx, false);
diff --git a/drivers/net/ethernet/sfc/efx.h b/drivers/net/ethernet/sfc/efx.h
index f11170bc48bf..50247dfe8f57 100644
--- a/drivers/net/ethernet/sfc/efx.h
+++ b/drivers/net/ethernet/sfc/efx.h
@@ -163,4 +163,17 @@ extern void efx_link_status_changed(struct efx_nic *efx);
 extern void efx_link_set_advertising(struct efx_nic *efx, u32);
 extern void efx_link_set_wanted_fc(struct efx_nic *efx, u8);
 
+static inline void efx_device_detach_sync(struct efx_nic *efx)
+{
+        struct net_device *dev = efx->net_dev;
+
+        /* Lock/freeze all TX queues so that we can be sure the
+         * TX scheduler is stopped when we're done and before
+         * netif_device_present() becomes false.
+         */
+        netif_tx_lock(dev);
+        netif_device_detach(dev);
+        netif_tx_unlock(dev);
+}
+
 #endif /* EFX_EFX_H */
diff --git a/drivers/net/ethernet/sfc/selftest.c b/drivers/net/ethernet/sfc/selftest.c
index f6651d35d615..2069f51b2aa9 100644
--- a/drivers/net/ethernet/sfc/selftest.c
+++ b/drivers/net/ethernet/sfc/selftest.c
@@ -722,7 +722,7 @@ int efx_selftest(struct efx_nic *efx, struct efx_self_tests *tests,
         /* 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);
+        efx_device_detach_sync(efx);
 
         if (efx->type->test_chip) {
                 rc_reset = efx->type->test_chip(efx, tests);