[3.13.y.z extended stable] Patch "s390/chsc: fix SEI usage on old FW levels" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    s390/chsc: fix SEI usage on old FW levels

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.3.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 8888c2926fdb9ffd21750449e9c9314c97bfe003 Mon Sep 17 00:00:00 2001
From: Sebastian Ott <sebott at linux.vnet.ibm.com>
Date: Tue, 15 Apr 2014 20:08:01 +0200
Subject: s390/chsc: fix SEI usage on old FW levels

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: Kamal Mostafa <kamal 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