From: James Smart Date: Mon, 19 Dec 2016 23:07:30 +0000 (-0800) Subject: scsi: lpfc: Add missing memory barrier X-Git-Tag: v3.18.83~24 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=70e2afb4c9d98955bff8b9ed266872e7accde459;p=thirdparty%2Fkernel%2Fstable.git scsi: lpfc: Add missing memory barrier [ Upstream commit 6b3b3bdb83b4ad51252d21bb13596db879e51850 ] 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 Signed-off-by: James Smart Reviewed-by: Hannes Reinecke Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c index 207a43d952fa4..42236ef89ab04 100644 --- a/drivers/scsi/lpfc/lpfc_sli.c +++ b/drivers/scsi/lpfc/lpfc_sli.c @@ -118,6 +118,8 @@ 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;