vhost_user_block, virtio-devices, block_util: Extract common block code

Extract the code that is used by vhost_user_block from the
virtio-devices crate to remove the dependencies on unrequired
functionality such as the virtio transports.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

vhost_user_block/Cargo.toml

@@ -5,6 +5,7 @@ authors = ["The Cloud Hypervisor Authors"]
 edition = "2018"
 
 [dependencies]
+block_util = { path = "../block_util" }
 clap = { version = "2.33.1", features=["wrap_help"] }
 epoll = ">=4.0.1"
 libc = "0.2.72"
@@ -14,6 +15,5 @@ qcow = { path = "../qcow" }
 vhost_user_backend = { path = "../vhost_user_backend" }
 vhost_rs = { git = "https://github.com/cloud-hypervisor/vhost", branch = "dragonball", package = "vhost", features = ["vhost-user-slave"] }
 virtio-bindings = "0.1.0"
-virtio-devices = { path = "../virtio-devices" }
 vm-memory = "0.2.1"
 vmm-sys-util = ">=0.3.1"

vhost_user_block/src/lib.rs

@@ -8,11 +8,12 @@
 //
 // SPDX-License-Identifier: (Apache-2.0 AND BSD-3-Clause)
 
+extern crate block_util;
 extern crate log;
 extern crate vhost_rs;
 extern crate vhost_user_backend;
-extern crate virtio_devices;
 
+use block_util::{build_disk_image_id, Request, VirtioBlockConfig};
 use libc::EFD_NONBLOCK;
 use log::*;
 use option_parser::{OptionParser, OptionParserError, Toggle};
@@ -37,8 +38,6 @@ use vhost_rs::vhost_user::Listener;
 use vhost_user_backend::{VhostUserBackend, VhostUserDaemon, Vring};
 use virtio_bindings::bindings::virtio_blk::*;
 use virtio_bindings::bindings::virtio_ring::VIRTIO_RING_F_EVENT_IDX;
-use virtio_devices::block::{build_disk_image_id, Request};
-use virtio_devices::VirtioBlockConfig;
 use vm_memory::ByteValued;
 use vm_memory::{Bytes, GuestMemoryMmap};
 use vmm_sys_util::eventfd::EventFd;