enic: move wmb closer to where needed: before writing posted_index to hw
Signed-off-by: Scott Feldman <scofeldm@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/enic/vnic_wq.h b/drivers/net/enic/vnic_wq.h
index 7081828..c826137 100644
--- a/drivers/net/enic/vnic_wq.h
+++ b/drivers/net/enic/vnic_wq.h
@@ -108,8 +108,15 @@
buf->len = len;
buf = buf->next;
- if (eop)
+ if (eop) {
+ /* Adding write memory barrier prevents compiler and/or CPU
+ * reordering, thus avoiding descriptor posting before
+ * descriptor is initialized. Otherwise, hardware can read
+ * stale descriptor fields.
+ */
+ wmb();
iowrite32(buf->index, &wq->ctrl->posted_index);
+ }
wq->to_use = buf;
wq->ring.desc_avail--;