[PATCH v4 10/42] virtio: simplify feature bit handling
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2014-11-25 16:54:31
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Subsystem:
the rest, virtio core · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
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 a3df817..0f44cff 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)) - dev->features |= (1ULL << 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