On loosely ordered memory systems (PPC for example), the WQE elements were being updated in memory, but not necessarily flushed before the separate doorbell was written to hw which would cause hw to dma the WQE element. Thus, the hardware occasionally received partially updated WQE data. Add the memory barrier after updating the WQE memory. Signed-off-by: Dick Kennedy <dick.kennedy@xxxxxxxxxxxx> Signed-off-by: James Smart <james.smart@xxxxxxxxxxxx> --- v2: revised for checkpatch warning - comment before wmb() drivers/scsi/lpfc/lpfc_sli.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c index d0ffcf3..5c8663f 100644 --- a/drivers/scsi/lpfc/lpfc_sli.c +++ b/drivers/scsi/lpfc/lpfc_sli.c @@ -120,6 +120,8 @@ lpfc_sli4_wq_put(struct lpfc_queue *q, union lpfc_wqe *wqe) if (q->phba->sli3_options & LPFC_SLI4_PHWQ_ENABLED) bf_set(wqe_wqid, &wqe->generic.wqe_com, q->queue_id); lpfc_sli_pcimem_bcopy(wqe, temp_wqe, q->entry_size); + /* ensure WQE bcopy flushed before doorbell write */ + wmb(); /* Update the host index before invoking device */ host_index = q->host_index; -- 2.5.0 -- 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
