From: Iyappan Subramanian <[email protected]> Date: Mon, 26 Jan 2015 13:12:23 -0800
>>> @@ -369,6 +369,8 @@ static int xgene_enet_process_ring(struct >>> xgene_enet_desc_ring *ring, >>> if (unlikely(xgene_enet_is_desc_slot_empty(raw_desc))) >>> break; >>> >>> + /* read fpqnum field after dataaddr field */ >>> + smp_rmb(); >>> if (is_rx_desc(raw_desc)) >>> ret = xgene_enet_rx_frame(ring, raw_desc); >>> else >> >> Reading your changelog, it looks like you need a plain rmb() here. > > rmb() translates into dsb, which in arm64 serializes everything > including instructions and thus expensive compared to dmb. > > Do you see any issue with smp_rmb() (which translates into dmb) ? smp_rmb() is not appropriate. You're not serializing accesses between two cpus, you're serializing the cpu with the device. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
