scsi: megaraid_sas: Fix data integrity failure for JBOD (passthrough) devices

Commit 5c8fb9ee4e89 ("megaraid_sas: return sync cache call with
success") modified the driver to successfully complete SYNCHRONIZE_CACHE
commands without passing them to the controller. Disk drive caches are
only explicitly managed by controller firmware when operating in RAID
mode. So this commit effectively disabled writeback cache flushing for
any drives used in JBOD mode, leading to data integrity failures.

[mkp: clarified patch description]

Fixes: 5c8fb9ee4e891eb3b83f2e32f81b864f050d24be
CC: stable@vger.kernel.org
Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 9ff57dee72d7b0ac20fd01e00283416864aa7cc1..d8b1fbd4c8aafc61e5e5491d5394440651a43a04 100644 (file)
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -1700,16 +1700,13 @@ megasas_queue_command(struct Scsi_Host *shost, struct scsi_cmnd *scmd)
                goto out_done;
        }
 
-       switch (scmd->cmnd[0]) {
-       case SYNCHRONIZE_CACHE:
-               /*
-                * FW takes care of flush cache on its own
-                * No need to send it down
-                */
+       /*
+        * FW takes care of flush cache on its own for Virtual Disk.
+        * No need to send it down for VD. For JBOD send SYNCHRONIZE_CACHE to FW.
+        */
+       if ((scmd->cmnd[0] == SYNCHRONIZE_CACHE) && MEGASAS_IS_LOGICAL(scmd)) {
                scmd->result = DID_OK << 16;
                goto out_done;
-       default:
-               break;
        }
 
        return instance->instancet->build_and_issue_cmd(instance, scmd);