@@ -601,7 +601,18 @@ bnad_cq_process(struct bnad *bnad, struct bna_ccb *ccb, int budget)
cq = ccb->sw_q;
cmpl = &cq[ccb->producer_index];
- while (cmpl->valid && (packets < budget)) {
+ while (packets < budget) {
+ if (!cmpl->valid)
+ break;
+ /* The 'valid' field is set by the adapter, only after writing
+ * the other fields of completion entry. Hence, do not load
+ * other fields of completion entry *before* the 'valid' is
+ * loaded. Adding the rmb() here prevents the compiler and/or
+ * CPU from reordering the reads which would potentially result
+ * in reading stale values in completion entry.
+ */
+ rmb();
+
BNA_UPDATE_PKT_CNT(pkt_rt, ntohs(cmpl->length));
if (bna_is_small_rxq(cmpl->rxq_id))
@@ -641,6 +652,16 @@ bnad_cq_process(struct bnad *bnad, struct bna_ccb *ccb, int budget)
if (!next_cmpl->valid)
break;
+ /* The 'valid' field is set by the adapter, only
+ * after writing the other fields of completion
+ * entry. Hence, do not load other fields of
+ * completion entry *before* the 'valid' is
+ * loaded. Adding the rmb() here prevents the
+ * compiler and/or CPU from reordering the reads
+ * which would potentially result in reading
+ * stale values in completion entry.
+ */
+ rmb();
len = ntohs(next_cmpl->length);
flags = ntohl(next_cmpl->flags);
Valid bit check for completion needs read fence, so that it does not get reordered with other loads. Signed-off-by: Rasesh Mody <rmody@brocade.com> --- drivers/net/ethernet/brocade/bna/bnad.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-)