linters: Fix clippy issues

Latest clippy version complains about our existing code for the
following reasons:

- trait objects without an explicit `dyn` are deprecated
- `...` range patterns are deprecated
- lint `clippy::const_static_lifetime` has been renamed to
  `clippy::redundant_static_lifetimes`
- unnecessary `unsafe` block
- unneeded return statement

All these issues have been fixed through this patch, and rustfmt has
been run to cleanup potential formatting errors due to those changes.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

vm-virtio/src/console.rs

@@ -57,7 +57,7 @@ struct ConsoleEpollHandler {
     mem: GuestMemoryMmap,
     interrupt_cb: Arc<VirtioInterrupt>,
     in_buffer: Arc<Mutex<VecDeque<u8>>>,
-    out: Box<io::Write + Send>,
+    out: Box<dyn io::Write + Send>,
     input_queue_evt: EventFd,
     output_queue_evt: EventFd,
     input_evt: EventFd,
@@ -321,13 +321,13 @@ pub struct Console {
     acked_features: u64,
     config: Arc<Mutex<VirtioConsoleConfig>>,
     input: Arc<ConsoleInput>,
-    out: Option<Box<io::Write + Send>>,
+    out: Option<Box<dyn io::Write + Send>>,
 }
 
 impl Console {
     /// Create a new virtio console device that gets random data from /dev/urandom.
     pub fn new(
-        out: Option<Box<io::Write + Send>>,
+        out: Option<Box<dyn io::Write + Send>>,
         cols: u16,
         rows: u16,
     ) -> io::Result<(Console, Arc<ConsoleInput>)> {

vm-virtio/src/device.rs

@@ -17,7 +17,7 @@ pub enum VirtioInterruptType {
 }
 
 pub type VirtioInterrupt = Box<
-    Fn(&VirtioInterruptType, Option<&Queue>) -> std::result::Result<(), std::io::Error>
+    dyn Fn(&VirtioInterruptType, Option<&Queue>) -> std::result::Result<(), std::io::Error>
         + Send
         + Sync,
 >;

vm-virtio/src/transport/pci_device.rs

@@ -223,7 +223,7 @@ pub struct VirtioPciDevice {
     msix_num: u16,
 
     // Virtio device reference and status
-    device: Box<VirtioDevice>,
+    device: Box<dyn VirtioDevice>,
     device_activated: bool,
 
     // PCI interrupts.
@@ -243,7 +243,11 @@ pub struct VirtioPciDevice {
 
 impl VirtioPciDevice {
     /// Constructs a new PCI transport for the given virtio device.
-    pub fn new(memory: GuestMemoryMmap, device: Box<VirtioDevice>, msix_num: u16) -> Result<Self> {
+    pub fn new(
+        memory: GuestMemoryMmap,
+        device: Box<dyn VirtioDevice>,
+        msix_num: u16,
+    ) -> Result<Self> {
         let mut queue_evts = Vec::new();
         for _ in device.queue_max_sizes().iter() {
             queue_evts.push(EventFd::new(EFD_NONBLOCK)?)
@@ -267,15 +271,15 @@ impl VirtioPciDevice {
         let (class, subclass) = match VirtioDeviceType::from(device.device_type()) {
             VirtioDeviceType::TYPE_NET => (
                 PciClassCode::NetworkController,
-                &PciNetworkControllerSubclass::EthernetController as &PciSubclass,
+                &PciNetworkControllerSubclass::EthernetController as &dyn PciSubclass,
             ),
             VirtioDeviceType::TYPE_BLOCK => (
                 PciClassCode::MassStorage,
-                &PciMassStorageSubclass::MassStorage as &PciSubclass,
+                &PciMassStorageSubclass::MassStorage as &dyn PciSubclass,
             ),
             _ => (
                 PciClassCode::Other,
-                &PciVirtioSubclass::NonTransitionalBase as &PciSubclass,
+                &PciVirtioSubclass::NonTransitionalBase as &dyn PciSubclass,
             ),
         };