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 <troy.kisky@boundarydevices.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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 @@
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 @@
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.
@@ -1475,7 +1483,6 @@
/* Mark the buffer empty */
status |= BD_ENET_RX_EMPTY;
- bdp->cbd_sc = cpu_to_fec16(status);
if (fep->bufdesc_ex) {
struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp;
@@ -1484,6 +1491,11 @@
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);
/* Update BD pointer to next entry */
bdp = fec_enet_get_nextdesc(bdp, &rxq->bd);