From: Brian King brking@linux.vnet.ibm.com
[ 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 --- drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c @@ -286,6 +286,9 @@ int bnx2x_tx_int(struct bnx2x *bp, struc 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;