ixgb: fix smp polling race condition

Moved interrupt masking to before requesting the interrupt from the OS.
Moved interrupt enable to after netif_poll_enable.  This fixes a racy
BUG() where polling would be running on another CPU at the same time
that netif_poll_enable would run.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index 0a0c876dcbdd..954894b5308c 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -247,6 +247,9 @@ ixgb_up(struct ixgb_adapter *adapter)
         ixgb_configure_rx(adapter);
         ixgb_alloc_rx_buffers(adapter);
 
+        /* disable interrupts and get the hardware into a known state */
+        IXGB_WRITE_REG(&adapter->hw, IMC, 0xffffffff);
+
 #ifdef CONFIG_PCI_MSI
         {
         boolean_t pcix = (IXGB_READ_REG(&adapter->hw, STATUS) & 
@@ -272,9 +275,6 @@ ixgb_up(struct ixgb_adapter *adapter)
                 return err;
         }
 
-        /* disable interrupts and get the hardware into a known state */
-        IXGB_WRITE_REG(&adapter->hw, IMC, 0xffffffff);
-
         if((hw->max_frame_size != max_frame) ||
                 (hw->max_frame_size !=
                 (IXGB_READ_REG(hw, MFS) >> IXGB_MFS_SHIFT))) {
@@ -295,11 +295,12 @@ ixgb_up(struct ixgb_adapter *adapter)
         }
 
         mod_timer(&adapter->watchdog_timer, jiffies);
-        ixgb_irq_enable(adapter);
 
 #ifdef CONFIG_IXGB_NAPI
         netif_poll_enable(netdev);
 #endif
+        ixgb_irq_enable(adapter);
+
         return 0;
 }