[Qemu-devel] [PULL for-4.0 4/4] hw/s390x/3270-ccw: avoid taking address of fields in packed struct

[Cornelia Huck <cohuck@redhat.com>]

From: Daniel P. Berrangé <berrange@redhat.com>

Compiling with GCC 9 complains

hw/s390x/3270-ccw.c: In function ‘emulated_ccw_3270_cb’:
hw/s390x/3270-ccw.c:81:19: error: taking address of packed member of ‘struct SCHIB’ may result in an unaligned pointer value [-Werror=address-of-packed-member]
   81 |         SCSW *s = &sch->curr_status.scsw;
      |                   ^~~~~~~~~~~~~~~~~~~~~~

This local variable is only present to save a little bit of
typing when setting the field later. Get rid of this to avoid
the warning about unaligned accesses.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20190329111104.17223-15-berrange@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
---
 hw/s390x/3270-ccw.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/s390x/3270-ccw.c b/hw/s390x/3270-ccw.c
index 2c8d16ccf7e2..14882242c3de 100644
--- a/hw/s390x/3270-ccw.c
+++ b/hw/s390x/3270-ccw.c
@@ -78,13 +78,13 @@ static int emulated_ccw_3270_cb(SubchDev *sch, CCW1 ccw)
 
     if (rc == -EIO) {
         /* I/O error, specific devices generate specific conditions */
-        SCSW *s = &sch->curr_status.scsw;
+        SCHIB *schib = &sch->curr_status;
 
         sch->curr_status.scsw.dstat = SCSW_DSTAT_UNIT_CHECK;
         sch->sense_data[0] = 0x40;    /* intervention-req */
-        s->ctrl &= ~SCSW_ACTL_START_PEND;
-        s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
-        s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
+        schib->scsw.ctrl &= ~SCSW_ACTL_START_PEND;
+        schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
+        schib->scsw.ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
                    SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
     }
 
-- 
2.17.2