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>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index d0a1d8a45c81..97aeb7dce5fc 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -137,14 +137,14 @@ static void lg_finalize_features(struct virtio_device *vdev)
         vring_transport_features(vdev);
 
         /*
-         * The vdev->feature array is a Linux bitmask: this isn't the same as a
-         * the simple array of bits used by lguest devices for features.  So we
-         * do this slow, manual conversion which is completely general.
+         * Since lguest is currently x86-only, we're little-endian.  That
+         * means we could just memcpy.  But it's not time critical, and in
+         * case someone copies this code, we do it the slow, obvious way.
          */
         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));
         }