[PATCH] Fix locking in gianfar

This patch fixes several bugs in the gianfar driver, including a major one
where spinlocks were horribly broken:

* Split gianfar locks into two types: TX and RX
* Made it so gfar_start() now clears RHALT
* Fixed a bug where calling gfar_start_xmit() with interrupts off would
corrupt the interrupt state
* Fixed a bug where a frame could potentially arrive, and never be handled
(if no more frames arrived
* Fixed a bug where the rx_work_limit would never be observed by the rx
completion code
* Fixed a bug where the interrupt handlers were not actually protected by
their spinlocks

Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 14 insertions, 6 deletions

diff --git a/drivers/net/gianfar_ethtool.c b/drivers/net/gianfar_ethtool.c
index 5de7b2e259dc..d69698c695ef 100644
--- a/drivers/net/gianfar_ethtool.c
+++ b/drivers/net/gianfar_ethtool.c
@@ -455,10 +455,14 @@ static int gfar_sringparam(struct net_device *dev, struct ethtool_ringparam *rva
 
                 /* Halt TX and RX, and process the frames which
                  * have already been received */
-                spin_lock_irqsave(&priv->lock, flags);
+                spin_lock_irqsave(&priv->txlock, flags);
+                spin_lock(&priv->rxlock);
+
                 gfar_halt(dev);
                 gfar_clean_rx_ring(dev, priv->rx_ring_size);
-                spin_unlock_irqrestore(&priv->lock, flags);
+
+                spin_unlock(&priv->rxlock);
+                spin_unlock_irqrestore(&priv->txlock, flags);
 
                 /* Now we take down the rings to rebuild them */
                 stop_gfar(dev);
@@ -488,10 +492,14 @@ static int gfar_set_rx_csum(struct net_device *dev, uint32_t data)
 
                 /* Halt TX and RX, and process the frames which
                  * have already been received */
-                spin_lock_irqsave(&priv->lock, flags);
+                spin_lock_irqsave(&priv->txlock, flags);
+                spin_lock(&priv->rxlock);
+
                 gfar_halt(dev);
                 gfar_clean_rx_ring(dev, priv->rx_ring_size);
-                spin_unlock_irqrestore(&priv->lock, flags);
+
+                spin_unlock(&priv->rxlock);
+                spin_unlock_irqrestore(&priv->txlock, flags);
 
                 /* Now we take down the rings to rebuild them */
                 stop_gfar(dev);
@@ -523,7 +531,7 @@ static int gfar_set_tx_csum(struct net_device *dev, uint32_t data)
         if (!(priv->einfo->device_flags & FSL_GIANFAR_DEV_HAS_CSUM))
                 return -EOPNOTSUPP;
 
-        spin_lock_irqsave(&priv->lock, flags);
+        spin_lock_irqsave(&priv->txlock, flags);
         gfar_halt(dev);
 
         if (data)
@@ -532,7 +540,7 @@ static int gfar_set_tx_csum(struct net_device *dev, uint32_t data)
                 dev->features &= ~NETIF_F_IP_CSUM;
 
         gfar_start(dev);
-        spin_unlock_irqrestore(&priv->lock, flags);
+        spin_unlock_irqrestore(&priv->txlock, flags);
 
         return 0;
 }