vhost: fix performance on LE hosts
commit 2751c9882b947292fcfb084c4f604e01724af804 ("vhost: cross-endian
support for legacy devices") introduced a minor regression: even with
cross-endian disabled, and even on LE host, vhost_is_little_endian is
checking is_le flag so there's always a branch.
To fix, simply check virtio_legacy_is_little_endian first.
Cc: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 4772862..d3f76744 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -183,10 +183,17 @@
return vq->acked_features & (1ULL << bit);
}
+#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
{
return vq->is_le;
}
+#else
+static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
+{
+ return virtio_legacy_is_little_endian() || vq->is_le;
+}
+#endif
/* Memory accessors */
static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)