bnx2x: fix memory barriers

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/bnx2x_main.c b/drivers/net/bnx2x/bnx2x_main.c
index 7a89182..e4dea11 100644
--- a/drivers/net/bnx2x/bnx2x_main.c
+++ b/drivers/net/bnx2x/bnx2x_main.c
@@ -2984,8 +2984,12 @@
 {
 	int func = BP_FUNC(bp);
 
-	/* Make sure that BD data is updated before writing the producer */
-	wmb();
+	/*
+	 * Make sure that BD data is updated before writing the producer:
+	 * BD data is written to the memory, the producer is read from the
+	 * memory, thus we need a full memory barrier to ensure the ordering.
+	 */
+	mb();
 
 	REG_WR16(bp, BAR_XSTRORM_INTMEM + XSTORM_SPQ_PROD_OFFSET(func),
 		 bp->spq_prod_idx);