Merge branch 'for-davem' of git://git.kernel.org/pub/scm/linux/kernel/git/bwh/sfc-next

Ben Hutchings says:

====================
1. Change the TX path to stop queues earlier and avoid returning
NETDEV_TX_BUSY.
2. Remove some inefficiencies in soft-TSO.
3. Fix various bugs involving device state transitions and/or reset
scheduling by error handlers.
4. Take advantage of my previous change to operstate initialisation.
5. Miscellaneous cleanup.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 410 insertions, 507 deletions

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 65a8d49106a4..a606db43c5ba 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -202,11 +202,21 @@ static void efx_stop_all(struct efx_nic *efx);
 
 #define EFX_ASSERT_RESET_SERIALISED(efx)                \
         do {                                            \
-                if ((efx->state == STATE_RUNNING) ||    \
+                if ((efx->state == STATE_READY) ||      \
                     (efx->state == STATE_DISABLED))     \
                         ASSERT_RTNL();                  \
         } while (0)
 
+static int efx_check_disabled(struct efx_nic *efx)
+{
+        if (efx->state == STATE_DISABLED) {
+                netif_err(efx, drv, efx->net_dev,
+                          "device is disabled due to earlier errors\n");
+                return -EIO;
+        }
+        return 0;
+}
+
 /**************************************************************************
  *
  * Event queue processing
@@ -630,6 +640,16 @@ static void efx_start_datapath(struct efx_nic *efx)
         efx->rx_buffer_order = get_order(efx->rx_buffer_len +
                                          sizeof(struct efx_rx_page_state));
 
+        /* We must keep at least one descriptor in a TX ring empty.
+         * We could avoid this when the queue size does not exactly
+         * match the hardware ring size, but it's not that important.
+         * Therefore we stop the queue when one more skb might fill
+         * the ring completely.  We wake it when half way back to
+         * empty.
+         */
+        efx->txq_stop_thresh = efx->txq_entries - efx_tx_max_skb_descs(efx);
+        efx->txq_wake_thresh = efx->txq_stop_thresh / 2;
+
         /* Initialise the channels */
         efx_for_each_channel(channel, efx) {
                 efx_for_each_channel_tx_queue(tx_queue, channel)
@@ -730,7 +750,11 @@ efx_realloc_channels(struct efx_nic *efx, u32 rxq_entries, u32 txq_entries)
         struct efx_channel *other_channel[EFX_MAX_CHANNELS], *channel;
         u32 old_rxq_entries, old_txq_entries;
         unsigned i, next_buffer_table = 0;
-        int rc = 0;
+        int rc;
+
+        rc = efx_check_disabled(efx);
+        if (rc)
+                return rc;
 
         /* Not all channels should be reallocated. We must avoid
          * reallocating their buffer table entries.
@@ -1365,6 +1389,8 @@ static void efx_start_interrupts(struct efx_nic *efx, bool may_keep_eventq)
 {
         struct efx_channel *channel;
 
+        BUG_ON(efx->state == STATE_DISABLED);
+
         if (efx->legacy_irq)
                 efx->legacy_irq_enabled = true;
         efx_nic_enable_interrupts(efx);
@@ -1382,6 +1408,9 @@ static void efx_stop_interrupts(struct efx_nic *efx, bool may_keep_eventq)
 {
         struct efx_channel *channel;
 
+        if (efx->state == STATE_DISABLED)
+                return;
+
         efx_mcdi_mode_poll(efx);
 
         efx_nic_disable_interrupts(efx);
@@ -1533,22 +1562,21 @@ static int efx_probe_all(struct efx_nic *efx)
         return rc;
 }
 
-/* Called after previous invocation(s) of efx_stop_all, restarts the port,
- * kernel transmit queues and NAPI processing, and ensures that the port is
- * scheduled to be reconfigured. This function is safe to call multiple
- * times when the NIC is in any state.
+/* If the interface is supposed to be running but is not, start
+ * the hardware and software data path, regular activity for the port
+ * (MAC statistics, link polling, etc.) and schedule the port to be
+ * reconfigured.  Interrupts must already be enabled.  This function
+ * is safe to call multiple times, so long as the NIC is not disabled.
+ * Requires the RTNL lock.
  */
 static void efx_start_all(struct efx_nic *efx)
 {
         EFX_ASSERT_RESET_SERIALISED(efx);
+        BUG_ON(efx->state == STATE_DISABLED);
 
         /* Check that it is appropriate to restart the interface. All
          * of these flags are safe to read under just the rtnl lock */
-        if (efx->port_enabled)
-                return;
-        if ((efx->state != STATE_RUNNING) && (efx->state != STATE_INIT))
-                return;
-        if (!netif_running(efx->net_dev))
+        if (efx->port_enabled || !netif_running(efx->net_dev))
                 return;
 
         efx_start_port(efx);
@@ -1582,11 +1610,11 @@ static void efx_flush_all(struct efx_nic *efx)
         cancel_work_sync(&efx->mac_work);
 }
 
-/* Quiesce hardware and software without bringing the link down.
- * Safe to call multiple times, when the nic and interface is in any
- * state. The caller is guaranteed to subsequently be in a position
- * to modify any hardware and software state they see fit without
- * taking locks. */
+/* Quiesce the hardware and software data path, and regular activity
+ * for the port without bringing the link down.  Safe to call multiple
+ * times with the NIC in almost any state, but interrupts should be
+ * enabled.  Requires the RTNL lock.
+ */
 static void efx_stop_all(struct efx_nic *efx)
 {
         EFX_ASSERT_RESET_SERIALISED(efx);
@@ -1739,8 +1767,6 @@ static int efx_ioctl(struct net_device *net_dev, struct ifreq *ifr, int cmd)
         struct efx_nic *efx = netdev_priv(net_dev);
         struct mii_ioctl_data *data = if_mii(ifr);
 
-        EFX_ASSERT_RESET_SERIALISED(efx);
-
         /* Convert phy_id from older PRTAD/DEVAD format */
         if ((cmd == SIOCGMIIREG || cmd == SIOCSMIIREG) &&
             (data->phy_id & 0xfc00) == 0x0400)
@@ -1820,13 +1846,14 @@ static void efx_netpoll(struct net_device *net_dev)
 static int efx_net_open(struct net_device *net_dev)
 {
         struct efx_nic *efx = netdev_priv(net_dev);
-        EFX_ASSERT_RESET_SERIALISED(efx);
+        int rc;
 
         netif_dbg(efx, ifup, efx->net_dev, "opening device on CPU %d\n",
                   raw_smp_processor_id());
 
-        if (efx->state == STATE_DISABLED)
-                return -EIO;
+        rc = efx_check_disabled(efx);
+        if (rc)