s390: vfio-ccw: Do not attempt to free no-op, test and tic cda.

[ Upstream commit 408358b50deaf59b07c82a7bff8c7e7cce031fae ]

Because we do not make use of the cda (channel data address) for test,
no-op ccws no address translation takes place. This means cda could
contain a guest address which we do not want to attempt to free. Let's
check the command type and skip cda free when it is not needed.

For a TIC ccw, ccw->cda points to either a ccw in an existing chain or
it points to a whole new allocated chain. In either case the data will
be freed when the owning chain is freed.

Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Message-Id: <1510068152-21988-1-git-send-email-jjherne@linux.vnet.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index f20b4d66c75f7f3480b967bf3a48eae58acba12d..4a39b54732d031ec65e48bf0a6c6f1a9e9b4abea 100644 (file)
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -330,6 +330,8 @@ static void ccwchain_cda_free(struct ccwchain *chain, int idx)
 {
        struct ccw1 *ccw = chain->ch_ccw + idx;
 
+       if (ccw_is_test(ccw) || ccw_is_noop(ccw) || ccw_is_tic(ccw))
+               return;
        if (!ccw->count)
                return;