drivers/vhost: Remove now-redundant read_barrier_depends()

Because READ_ONCE() now implies read_barrier_depends(), the
read_barrier_depends() in next_desc() is now redundant.  This commit
therefore removes it and the related comments.

Signed-off-by: Paul E. McKenney <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
This commit is contained in:
Paul E. McKenney 2017-11-27 09:45:10 -08:00
commit 3a5db0b108

View file

@ -1877,12 +1877,7 @@ static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
return -1U;
/* Check they're not leading us off end of descriptors. */
next = vhost16_to_cpu(vq, desc->next);
/* Make sure compiler knows to grab that: we don't want it changing! */
/* We will use the result as an index in an array, so most
* architectures only need a compiler barrier here. */
read_barrier_depends();
next = vhost16_to_cpu(vq, READ_ONCE(desc->next));
return next;
}