RDMA/cxgb4: rmb() after reading valid gen bit
Some HW platforms can reorder read operations, so we must rmb() after
we see a valid gen bit in a CQE but before we read any other fields
from the CQE.
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/hw/cxgb4/t4.h b/drivers/infiniband/hw/cxgb4/t4.h
index 931bfd1..1f329fa 100644
--- a/drivers/infiniband/hw/cxgb4/t4.h
+++ b/drivers/infiniband/hw/cxgb4/t4.h
@@ -620,6 +620,9 @@
printk(KERN_ERR MOD "cq overflow cqid %u\n", cq->cqid);
BUG_ON(1);
} else if (t4_valid_cqe(cq, &cq->queue[cq->cidx])) {
+
+ /* Ensure CQE is flushed to memory */
+ rmb();
*cqe = &cq->queue[cq->cidx];
ret = 0;
} else