bnx2x: Prevent load reordering in tx completion processing
[ Upstream commit ea811b795df24644a8eb760b493c43fba4450677 ]
This patch fixes an issue seen on Power systems with bnx2x which results
in the skb is NULL WARN_ON in bnx2x_free_tx_pkt firing due to the skb
pointer getting loaded in bnx2x_free_tx_pkt prior to the hw_cons
load in bnx2x_tx_int. Adding a read memory barrier resolves the issue.
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index 2cd1dcd..efe1268 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -286,6 +286,9 @@
hw_cons = le16_to_cpu(*txdata->tx_cons_sb);
sw_cons = txdata->tx_pkt_cons;
+ /* Ensure subsequent loads occur after hw_cons */
+ smp_rmb();
+
while (sw_cons != hw_cons) {
u16 pkt_cons;