GenWQE: Fix problem when reading HSI and Retc

This patch fixes a problem we found during debug on PPC64 when
reading HSI status and Retc.

Signed-off-by: Eberhard S. Amann <esa@linux.vnet.ibm.com>
Signed-off-by: Frank Haverkamp <haver@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/genwqe/card_ddcb.c b/drivers/misc/genwqe/card_ddcb.c
index f105750..51480e4 100644 (file)
--- a/drivers/misc/genwqe/card_ddcb.c
+++ b/drivers/misc/genwqe/card_ddcb.c
@@ -390,8 +390,9 @@ static int genwqe_check_ddcb_queue(struct genwqe_dev *cd,
                    0x00000000)
                        goto go_home; /* not completed, continue waiting */
 
-               /* Note: DDCB could be purged */
+               wmb();  /*  Add sync to decouple prev. read operations */
 
+               /* Note: DDCB could be purged */
                req = queue->ddcb_req[queue->ddcb_act];
                if (req == NULL) {
                        /* this occurs if DDCB is purged, not an error */