bnx2x: Protect a SM state change

Bug fix: Protect the statistics state machine state update with a
spinlock.  Otherwise there was a race condition that would cause the
statistics to stay enabled despite the fact that they were disabled in
the LINK_DOWN event handler.

Signed-off-by: Vladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bnx2x.h b/drivers/net/bnx2x.h
index 8bd2368..bb0872a 100644
--- a/drivers/net/bnx2x.h
+++ b/drivers/net/bnx2x.h
@@ -1062,6 +1062,10 @@
 
 	/* used to synchronize stats collecting */
 	int			stats_state;
+
+	/* used for synchronization of concurrent threads statistics handling */
+	spinlock_t		stats_lock;
+
 	/* used by dmae command loader */
 	struct dmae_command	stats_dmae;
 	int			executer_idx;