bnx2x: Prevent restarting Tx during bnx2x_nic_unload

Tx queues were stopped before  bp->state was changed to a value different 
from BNX2X_STATE_OPEN, which allowed the bnx2x_tx_int() called from the 
NAPI context to re-enable it. This then allowed the netdev->ndo_start_xmit() 
to be called in the middle of the function reset and rings freeing. 

This patch changes bp->state to a value different 
from BNX2X_STATE_OPEN BEFORE disabling the Tx queues in order to restore the
broken protection against the above race in the bnx2x_tx_int().

Signed-off-by: Vladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/net/bnx2x/bnx2x_cmn.c b/drivers/net/bnx2x/bnx2x_cmn.c
index 5b0dba6d4efa..d724a18b5285 100644
--- a/drivers/net/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/bnx2x/bnx2x_cmn.c
@@ -1989,14 +1989,20 @@ int bnx2x_nic_unload(struct bnx2x *bp, int unload_mode)
                 return -EINVAL;
         }
 
+        /*
+         * It's important to set the bp->state to the value different from
+         * BNX2X_STATE_OPEN and only then stop the Tx. Otherwise bnx2x_tx_int()
+         * may restart the Tx from the NAPI context (see bnx2x_tx_int()).
+         */
+        bp->state = BNX2X_STATE_CLOSING_WAIT4_HALT;
+        smp_mb();
+
         /* Stop Tx */
         bnx2x_tx_disable(bp);
 
 #ifdef BCM_CNIC
         bnx2x_cnic_notify(bp, CNIC_CTL_STOP_CMD);
 #endif
-        bp->state = BNX2X_STATE_CLOSING_WAIT4_HALT;
-        smp_mb();
 
         bp->rx_mode = BNX2X_RX_MODE_NONE;