[PATCH net-next V2 7/8] net: fec: don't transfer ownership until descriptor write is complete

If you don't own it, you shouldn't write to it.

Signed-off-by: Troy Kisky <redacted>
---
  drivers/net/ethernet/freescale/fec_main.c | 14 +++++++++++++-
  1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index ca2708d..97ca72a 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c

@@ -390,6 +390,10 @@ fec_enet_txq_submit_frag_skb(struct fec_enet_priv_tx_q *txq,

  		bdp->cbd_bufaddr = cpu_to_fec32(addr);
  		bdp->cbd_datlen = cpu_to_fec16(frag_len);
+		/* Make sure the updates to rest of the descriptor are
+		 * performed before transferring ownership.
+		 */
+		wmb();
  		bdp->cbd_sc = cpu_to_fec16(status);
  	}

@@ -499,6 +503,10 @@ static int fec_enet_txq_submit_skb(struct fec_enet_priv_tx_q *txq,

  	bdp->cbd_datlen = cpu_to_fec16(buflen);
  	bdp->cbd_bufaddr = cpu_to_fec32(addr);
+	/* Make sure the updates to rest of the descriptor are performed before
+	 * transferring ownership.
+	 */
+	wmb();

  	/* Send it on its way.  Tell FEC it's ready, interrupt when done,
  	 * it's the last BD of the frame, and to put the CRC on the end.

@@ -1484,6 +1491,11 @@ rx_processing_done:
  			ebdp->cbd_prot = 0;
  			ebdp->cbd_bdu = 0;
  		}
+		/* Make sure the updates to rest of the descriptor are
+		 * performed before transferring ownership.
+		 */
+		wmb();
+		bdp->cbd_sc = cpu_to_fec16(status);