[PATCH net-next 07/40] net: fec: don't transfer ownership until descriptor write is complete

[Troy Kisky]

Signed-off-by: Troy Kisky <troy.ki...@boundarydevices.com>
---
 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 e8f35fb..b87f80d 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -388,6 +388,10 @@ fec_enet_txq_submit_frag_skb(struct fec_enet_priv_tx_q 
*txq,
 
                bdp->cbd_bufaddr = addr;
                bdp->cbd_datlen = frag_len;
+               /* Make sure the updates to rest of the descriptor are
+                * performed before transferring ownership.
+                */
+               wmb();
                bdp->cbd_sc = status;
        }
 
@@ -497,6 +501,10 @@ static int fec_enet_txq_submit_skb(struct 
fec_enet_priv_tx_q *txq,
 
        bdp->cbd_datlen = buflen;
        bdp->cbd_bufaddr = 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.
@@ -1467,7 +1475,6 @@ rx_processing_done:
 
                /* Mark the buffer empty */
                status |= BD_ENET_RX_EMPTY;
-               bdp->cbd_sc = status;
 
                if (fep->bufdesc_ex) {
                        struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp;
@@ -1476,6 +1483,11 @@ 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 = status;
 
                /* Update BD pointer to next entry */
                bdp = fec_enet_get_nextdesc(bdp, &rxq->bd);
-- 
2.5.0