[PATCH v7 13/46] virtio: simplify feature bit handling

Michael S. Tsirkin
2014-11-30T15:10:42Z

Now that we use u64 for bits, we can simply & them together.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
drivers/virtio/virtio.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 9248125..3e78f4b 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -160,6 +160,7 @@ static int virtio_dev_probe(struct device *_d)
struct virtio_device *dev = dev_to_virtio(_d);
struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
u64 device_features;
+ u64 driver_features;
unsigned status;

/* We have a driver! */
@@ -168,15 +169,16 @@ static int virtio_dev_probe(struct device *_d)
/* Figure out what features the device supports. */
device_features = dev->config->get_features(dev);

- /* Features supported by both device and driver into dev->features. */
- dev->features = 0;
+ /* Figure out what features the driver supports. */
+ driver_features = 0;
for (i = 0; i < drv->feature_table_size; i++) {
unsigned int f = drv->feature_table[i];
BUG_ON(f >= 64);
- if (device_features & (1ULL << f))
- __virtio_set_bit(dev, f);
+ driver_features |= (1ULL << f);
}

+ dev->features = driver_features & device_features;
+
/* Transport features always preserved to pass to finalize_features. */
for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
if (device_features & (1ULL << i))
--
MST