gianfar: Remove clean_rx_ring race from gfar_ethtool

gfar_clean_rx_ring() was designed to be called from napi
(rx softirq) context to do the Rx processing. Calling it
from a process context like this is a bug as it will
clearly race with the napi Rx processing.

There's also no point in initializing num_txbdfree since
startup_gfar() already does that, when bringing the device
up again (after reset). Changing num_txbdfree "on-the-fly"
like this is also subject to race conditions.  num_txbdfree
is handled by the Tx processing path and the device reset
procedure.  Also, don't assume that num_rx_queues is always
equal to num_tx_queues.

Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 55 deletions

diff --git a/drivers/net/ethernet/freescale/gianfar_ethtool.c b/drivers/net/ethernet/freescale/gianfar_ethtool.c
index 69fab72b8a8d..19557ec31f33 100644
--- a/drivers/net/ethernet/freescale/gianfar_ethtool.c
+++ b/drivers/net/ethernet/freescale/gianfar_ethtool.c
@@ -44,9 +44,6 @@
 
 #include "gianfar.h"
 
-extern int gfar_clean_rx_ring(struct gfar_priv_rx_q *rx_queue,
-                              int rx_work_limit);
-
 #define GFAR_MAX_COAL_USECS 0xffff
 #define GFAR_MAX_COAL_FRAMES 0xff
 static void gfar_fill_stats(struct net_device *dev, struct ethtool_stats *dummy,
@@ -466,15 +463,13 @@ static void gfar_gringparam(struct net_device *dev,
 }
 
 /* Change the current ring parameters, stopping the controller if
- * necessary so that we don't mess things up while we're in
- * motion.  We wait for the ring to be clean before reallocating
- * the rings.
+ * necessary so that we don't mess things up while we're in motion.
  */
 static int gfar_sringparam(struct net_device *dev,
                            struct ethtool_ringparam *rvals)
 {
         struct gfar_private *priv = netdev_priv(dev);
-        int err = 0, i = 0;
+        int err = 0, i;
 
         if (rvals->rx_pending > GFAR_RX_MAX_RING_SIZE)
                 return -EINVAL;
@@ -492,38 +487,15 @@ static int gfar_sringparam(struct net_device *dev,
                 return -EINVAL;
         }
 
-
-        if (dev->flags & IFF_UP) {
-                unsigned long flags;
-
-                /* Halt TX and RX, and process the frames which
-                 * have already been received
-                 */
-                local_irq_save(flags);
-                lock_tx_qs(priv);
-                lock_rx_qs(priv);
-
-                gfar_halt(priv);
-
-                unlock_rx_qs(priv);
-                unlock_tx_qs(priv);
-                local_irq_restore(flags);
-
-                for (i = 0; i < priv->num_rx_queues; i++)
-                        gfar_clean_rx_ring(priv->rx_queue[i],
-                                           priv->rx_queue[i]->rx_ring_size);
-
-                /* Now we take down the rings to rebuild them */
+        if (dev->flags & IFF_UP)
                 stop_gfar(dev);
-        }
 
-        /* Change the size */
-        for (i = 0; i < priv->num_rx_queues; i++) {
+        /* Change the sizes */
+        for (i = 0; i < priv->num_rx_queues; i++)
                 priv->rx_queue[i]->rx_ring_size = rvals->rx_pending;
+
+        for (i = 0; i < priv->num_tx_queues; i++)
                 priv->tx_queue[i]->tx_ring_size = rvals->tx_pending;
-                priv->tx_queue[i]->num_txbdfree =
-                        priv->tx_queue[i]->tx_ring_size;
-        }
 
         /* Rebuild the rings with the new size */
         if (dev->flags & IFF_UP) {
@@ -607,10 +579,8 @@ static int gfar_spauseparam(struct net_device *dev,
 
 int gfar_set_features(struct net_device *dev, netdev_features_t features)
 {
-        struct gfar_private *priv = netdev_priv(dev);
-        unsigned long flags;
-        int err = 0, i = 0;
         netdev_features_t changed = dev->features ^ features;
+        int err = 0;
 
         if (changed & (NETIF_F_HW_VLAN_CTAG_TX|NETIF_F_HW_VLAN_CTAG_RX))
                 gfar_vlan_mode(dev, features);
@@ -619,23 +589,6 @@ int gfar_set_features(struct net_device *dev, netdev_features_t features)
                 return 0;
 
         if (dev->flags & IFF_UP) {
-                /* Halt TX and RX, and process the frames which
-                 * have already been received
-                 */
-                local_irq_save(flags);
-                lock_tx_qs(priv);
-                lock_rx_qs(priv);
-
-                gfar_halt(priv);
-
-                unlock_tx_qs(priv);
-                unlock_rx_qs(priv);
-                local_irq_restore(flags);
-
-                for (i = 0; i < priv->num_rx_queues; i++)
-                        gfar_clean_rx_ring(priv->rx_queue[i],
-                                           priv->rx_queue[i]->rx_ring_size);
-
                 /* Now we take down the rings to rebuild them */
                 stop_gfar(dev);