[PATCH 3.10 52/80] s390/dasd: prevent incorrect length error under z/VM after PAV changes

From: Greg Kroah-Hartman
Date: Tue Mar 01 2016 - 21:23:00 EST


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

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

From: Stefan Haberland <stefan.haberland@xxxxxxxxxx>

commit 020bf042e5b397479c1174081b935d0ff15d1a64 upstream.

The channel checks the specified length and the provided amount of
data for CCWs and provides an incorrect length error if the size does
not match. Under z/VM with simulation activated the length may get
changed. Having the suppress length indication bit set is stated as
good CCW coding practice and avoids errors under z/VM.

Signed-off-by: Stefan Haberland <stefan.haberland@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/s390/block/dasd_alias.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/s390/block/dasd_alias.c
+++ b/drivers/s390/block/dasd_alias.c
@@ -722,7 +722,7 @@ static int reset_summary_unit_check(stru
ASCEBC((char *) &cqr->magic, 4);
ccw = cqr->cpaddr;
ccw->cmd_code = DASD_ECKD_CCW_RSCK;
- ccw->flags = 0 ;
+ ccw->flags = CCW_FLAG_SLI;
ccw->count = 16;
ccw->cda = (__u32)(addr_t) cqr->data;
((char *)cqr->data)[0] = reason;