Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[cascardo/linux.git] / drivers / lguest / lguest_device.c

diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index d0a1d8a..89088d6 100644 (file)
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -94,7 +94,7 @@ static unsigned desc_size(const struct lguest_device_desc *desc)
 }
 
 /* This gets the device's feature bits. */
-static u32 lg_get_features(struct virtio_device *vdev)
+static u64 lg_get_features(struct virtio_device *vdev)
 {
        unsigned int i;
        u32 features = 0;
@@ -126,7 +126,7 @@ static void status_notify(struct virtio_device *vdev)
  * sorted out, this routine is called so we can tell the Host which features we
  * understand and accept.
  */
-static void lg_finalize_features(struct virtio_device *vdev)
+static int lg_finalize_features(struct virtio_device *vdev)
 {
        unsigned int i, bits;
        struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
@@ -136,20 +136,25 @@ static void lg_finalize_features(struct virtio_device *vdev)
        /* Give virtio_ring a chance to accept features. */
        vring_transport_features(vdev);
 
+       /* Make sure we don't have any features > 32 bits! */
+       BUG_ON((u32)vdev->features != vdev->features);
+
        /*
-        * 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));
        }
 
        /* Tell Host we've finished with this device's feature negotiation */
        status_notify(vdev);
+
+       return 0;
 }
 
 /* Once they've found a field, getting a copy of it is easy. */