From: Edward Cree <ecree.xilinx@gmail.com>
Date: Wed, 20 Jul 2022 19:33:49 +0100
Subject: sfc: attach/detach EF100 representors along with their owning PF
Patch-mainline: v6.0-rc1
Git-commit: 84e7fc2591f72987b43da91b3fdb01a196204379
References: jsc#PED-1565

Since representors piggy-back on the PF's queues for TX, they can
 only accept new TXes while the PF is up.  Thus, any operation which
 detaches the PF must first detach all its VFreps.

Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/sfc/ef100_netdev.c |    3 ++
 drivers/net/ethernet/sfc/ef100_rep.c    |   11 ++++++++-
 drivers/net/ethernet/sfc/efx.h          |    9 +++++++-
 drivers/net/ethernet/sfc/efx_common.c   |   36 ++++++++++++++++++++++++++++++++
 drivers/net/ethernet/sfc/efx_common.h   |    3 ++
 5 files changed, 59 insertions(+), 3 deletions(-)

--- a/drivers/net/ethernet/sfc/ef100_netdev.c
+++ b/drivers/net/ethernet/sfc/ef100_netdev.c
@@ -85,6 +85,7 @@ static int ef100_net_stop(struct net_dev
 	netif_dbg(efx, ifdown, efx->net_dev, "closing on CPU %d\n",
 		  raw_smp_processor_id());
 
+	efx_detach_reps(efx);
 	netif_stop_queue(net_dev);
 	efx_stop_all(efx);
 	efx_mcdi_mac_fini_stats(efx);
@@ -176,6 +177,8 @@ static int ef100_net_open(struct net_dev
 	mutex_unlock(&efx->mac_lock);
 
 	efx->state = STATE_NET_UP;
+	if (netif_running(efx->net_dev))
+		efx_attach_reps(efx);
 
 	return 0;
 
--- a/drivers/net/ethernet/sfc/ef100_rep.c
+++ b/drivers/net/ethernet/sfc/ef100_rep.c
@@ -132,8 +132,13 @@ static struct efx_rep *efx_ef100_rep_cre
 	spin_lock_bh(&efx->vf_reps_lock);
 	list_add_tail(&efv->list, &efx->vf_reps);
 	spin_unlock_bh(&efx->vf_reps_lock);
-	netif_carrier_off(net_dev);
-	netif_tx_stop_all_queues(net_dev);
+	if (netif_running(efx->net_dev) && efx->state == STATE_NET_UP) {
+		netif_device_attach(net_dev);
+		netif_carrier_on(net_dev);
+	} else {
+		netif_carrier_off(net_dev);
+		netif_tx_stop_all_queues(net_dev);
+	}
 	rtnl_unlock();
 
 	net_dev->netdev_ops = &efx_ef100_rep_netdev_ops;
@@ -171,9 +176,11 @@ static void efx_ef100_rep_destroy_netdev
 {
 	struct efx_nic *efx = efv->parent;
 
+	rtnl_lock();
 	spin_lock_bh(&efx->vf_reps_lock);
 	list_del(&efv->list);
 	spin_unlock_bh(&efx->vf_reps_lock);
+	rtnl_unlock();
 	free_netdev(efv->net_dev);
 }
 
--- a/drivers/net/ethernet/sfc/efx.h
+++ b/drivers/net/ethernet/sfc/efx.h
@@ -12,6 +12,7 @@
 #include "net_driver.h"
 #include "ef100_rx.h"
 #include "ef100_tx.h"
+#include "efx_common.h"
 #include "filter.h"
 
 int efx_net_open(struct net_device *net_dev);
@@ -206,6 +207,9 @@ static inline void efx_device_detach_syn
 {
 	struct net_device *dev = efx->net_dev;
 
+	/* We must stop reps (which use our TX) before we stop ourselves. */
+	efx_detach_reps(efx);
+
 	/* 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.
@@ -217,8 +221,11 @@ static inline void efx_device_detach_syn
 
 static inline void efx_device_attach_if_not_resetting(struct efx_nic *efx)
 {
-	if ((efx->state != STATE_DISABLED) && !efx->reset_pending)
+	if ((efx->state != STATE_DISABLED) && !efx->reset_pending) {
 		netif_device_attach(efx->net_dev);
+		if (efx->state == STATE_NET_UP)
+			efx_attach_reps(efx);
+	}
 }
 
 static inline bool efx_rwsem_assert_write_locked(struct rw_semaphore *sem)
--- a/drivers/net/ethernet/sfc/efx_common.c
+++ b/drivers/net/ethernet/sfc/efx_common.c
@@ -24,6 +24,7 @@
 #include "mcdi_port_common.h"
 #include "io.h"
 #include "mcdi_pcol.h"
+#include "ef100_rep.h"
 
 static unsigned int debug = (NETIF_MSG_DRV | NETIF_MSG_PROBE |
 			     NETIF_MSG_LINK | NETIF_MSG_IFDOWN |
@@ -1391,3 +1392,38 @@ int efx_get_phys_port_name(struct net_de
 		return -EINVAL;
 	return 0;
 }
+
+void efx_detach_reps(struct efx_nic *efx)
+{
+	struct net_device *rep_dev;
+	struct efx_rep *efv;
+
+	ASSERT_RTNL();
+	netif_dbg(efx, drv, efx->net_dev, "Detaching VF representors\n");
+	list_for_each_entry(efv, &efx->vf_reps, list) {
+		rep_dev = efv->net_dev;
+		if (!rep_dev)
+			continue;
+		netif_carrier_off(rep_dev);
+		/* See efx_device_detach_sync() */
+		netif_tx_lock_bh(rep_dev);
+		netif_tx_stop_all_queues(rep_dev);
+		netif_tx_unlock_bh(rep_dev);
+	}
+}
+
+void efx_attach_reps(struct efx_nic *efx)
+{
+	struct net_device *rep_dev;
+	struct efx_rep *efv;
+
+	ASSERT_RTNL();
+	netif_dbg(efx, drv, efx->net_dev, "Attaching VF representors\n");
+	list_for_each_entry(efv, &efx->vf_reps, list) {
+		rep_dev = efv->net_dev;
+		if (!rep_dev)
+			continue;
+		netif_tx_wake_all_queues(rep_dev);
+		netif_carrier_on(rep_dev);
+	}
+}
--- a/drivers/net/ethernet/sfc/efx_common.h
+++ b/drivers/net/ethernet/sfc/efx_common.h
@@ -111,4 +111,7 @@ int efx_get_phys_port_id(struct net_devi
 
 int efx_get_phys_port_name(struct net_device *net_dev,
 			   char *name, size_t len);
+
+void efx_detach_reps(struct efx_nic *efx);
+void efx_attach_reps(struct efx_nic *efx);
 #endif