virtio: use u32, not bitmap for features

It seemed like a good idea to use bitmap for features
in struct virtio_device, but it's actually a pain,
and seems to become even more painful when we get more
than 32 feature bits.  Just change it to a u32 for now.

Based on patch by Rusty.

Suggested-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>

2 files changed, 10 insertions, 15 deletions

diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index 643129070c51..fcd312d0c018 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -106,7 +106,7 @@ static void kvm_finalize_features(struct virtio_device *vdev)
         memset(out_features, 0, desc->feature_len);
         bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
         for (i = 0; i < bits; i++) {
-                if (test_bit(i, vdev->features))
+                if (__virtio_test_bit(vdev, i))
                         out_features[i / 8] |= (1 << (i % 8));
         }
 }
diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index bda52f18e967..1dbee95838fe 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -701,7 +701,6 @@ static void virtio_ccw_finalize_features(struct virtio_device *vdev)
 {
         struct virtio_ccw_device *vcdev = to_vc_device(vdev);
         struct virtio_feature_desc *features;
-        int i;
         struct ccw1 *ccw;
 
         ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
@@ -715,19 +714,15 @@ static void virtio_ccw_finalize_features(struct virtio_device *vdev)
         /* Give virtio_ring a chance to accept features. */
         vring_transport_features(vdev);
 
-        for (i = 0; i < sizeof(*vdev->features) / sizeof(features->features);
-             i++) {
-                int highbits = i % 2 ? 32 : 0;
-                features->index = i;
-                features->features = cpu_to_le32(vdev->features[i / 2]
-                                                 >> highbits);
-                /* Write the feature bits to the host. */
-                ccw->cmd_code = CCW_CMD_WRITE_FEAT;
-                ccw->flags = 0;
-                ccw->count = sizeof(*features);
-                ccw->cda = (__u32)(unsigned long)features;
-                ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
-        }
+        features->index = 0;
+        features->features = cpu_to_le32(vdev->features);
+        /* Write the feature bits to the host. */
+        ccw->cmd_code = CCW_CMD_WRITE_FEAT;
+        ccw->flags = 0;
+        ccw->count = sizeof(*features);
+        ccw->cda = (__u32)(unsigned long)features;
+        ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
+
 out_free:
         kfree(features);
         kfree(ccw);