[PATCH 3.11 51/70] s390/chsc: fix SEI usage on old FW levels

[Luis Henriques]

3.11.10.10 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sebastian Ott <sebott at linux.vnet.ibm.com>

commit 06cd7a874ec6e09d151aeb1fa8600e14f1ff89f6 upstream.

Using a notification type mask for the store event information chsc
is unsupported on some firmware levels. Retry SEI with that mask set
to zero (which is the old way of requesting only channel subsystem
related events).

Reported-and-tested-by: Stefan Haberland <stefan.haberland at de.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar at linux.vnet.ibm.com>
Signed-off-by: Sebastian Ott <sebott at linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky at de.ibm.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/s390/cio/chsc.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index 13299f9..ec0951a 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -560,18 +560,27 @@ static void chsc_process_sei_nt0(struct chsc_sei_nt0_area *sei_area)
 
 static void chsc_process_event_information(struct chsc_sei *sei, u64 ntsm)
 {
-	do {
+	static int ntsm_unsupported;
+
+	while (true) {
 		memset(sei, 0, sizeof(*sei));
 		sei->request.length = 0x0010;
 		sei->request.code = 0x000e;
-		sei->ntsm = ntsm;
+		if (!ntsm_unsupported)
+			sei->ntsm = ntsm;
 
 		if (chsc(sei))
 			break;
 
 		if (sei->response.code != 0x0001) {
-			CIO_CRW_EVENT(2, "chsc: sei failed (rc=%04x)\n",
-				      sei->response.code);
+			CIO_CRW_EVENT(2, "chsc: sei failed (rc=%04x, ntsm=%llx)\n",
+				      sei->response.code, sei->ntsm);
+
+			if (sei->response.code == 3 && sei->ntsm) {
+				/* Fallback for old firmware. */
+				ntsm_unsupported = 1;
+				continue;
+			}
 			break;
 		}
 
@@ -587,7 +596,10 @@ static void chsc_process_event_information(struct chsc_sei *sei, u64 ntsm)
 			CIO_CRW_EVENT(2, "chsc: unhandled nt: %d\n", sei->nt);
 			break;
 		}
-	} while (sei->u.nt0_area.flags & 0x80);
+
+		if (!(sei->u.nt0_area.flags & 0x80))
+			break;
+	}
 }
 
 /*
-- 
1.9.1