The megaraid_sas HBA only has a single register for I/O submission, which will be hit pretty hard with scsi-mq. To ensure that the PCI writes have made it across we need to add a mmio barrier after each write; otherwise I've been seeing spurious command completions and I/O stalls. Signed-off-by: Hannes Reinecke <hare@xxxxxxxx> --- drivers/scsi/megaraid/megaraid_sas_fusion.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c b/drivers/scsi/megaraid/megaraid_sas_fusion.c index aba53c0..729a654 100644 --- a/drivers/scsi/megaraid/megaraid_sas_fusion.c +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c @@ -196,6 +196,7 @@ inline void megasas_return_cmd_fusion(struct megasas_instance *instance, le32_to_cpu(req_desc->u.low)); writeq(req_data, &instance->reg_set->inbound_low_queue_port); + mmiowb(); #else unsigned long flags; -- 1.8.5.6 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
