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>

devices/src/bus.rs

@@ -77,7 +77,7 @@ impl PartialOrd for BusRange {
 /// only restriction is that no two devices can overlap in this address space.
 #[derive(Clone, Default)]
 pub struct Bus {
-    devices: BTreeMap<BusRange, Arc<Mutex<BusDevice>>>,
+    devices: BTreeMap<BusRange, Arc<Mutex<dyn BusDevice>>>,
 }
 
 impl Bus {
@@ -88,7 +88,7 @@ impl Bus {
         }
     }
 
-    fn first_before(&self, addr: u64) -> Option<(BusRange, &Mutex<BusDevice>)> {
+    fn first_before(&self, addr: u64) -> Option<(BusRange, &Mutex<dyn BusDevice>)> {
         let (range, dev) = self
             .devices
             .range(..=BusRange { base: addr, len: 1 })
@@ -97,7 +97,7 @@ impl Bus {
         Some((*range, dev))
     }
 
-    pub fn resolve(&self, addr: u64) -> Option<(u64, u64, &Mutex<BusDevice>)> {
+    pub fn resolve(&self, addr: u64) -> Option<(u64, u64, &Mutex<dyn BusDevice>)> {
         if let Some((range, dev)) = self.first_before(addr) {
             let offset = addr - range.base;
             if offset < range.len {
@@ -108,7 +108,7 @@ impl Bus {
     }
 
     /// Puts the given device at the given address space.
-    pub fn insert(&mut self, device: Arc<Mutex<BusDevice>>, base: u64, len: u64) -> Result<()> {
+    pub fn insert(&mut self, device: Arc<Mutex<dyn BusDevice>>, base: u64, len: u64) -> Result<()> {
         if len == 0 {
             return Err(Error::Overlap);
         }

devices/src/ioapic.rs

@@ -188,7 +188,6 @@ impl BusDevice for Ioapic {
             IOWIN_OFF => self.ioapic_write(value),
             _ => {
                 error!("IOAPIC: failed writing at offset {}", offset);
-                return;
             }
         }
     }

devices/src/legacy/serial.rs

@@ -55,7 +55,7 @@ const DEFAULT_BAUD_DIVISOR: u16 = 12; // 9600 bps
 pub struct Serial {
     interrupt_enable: u8,
     interrupt_identification: u8,
-    interrupt: Box<Interrupt>,
+    interrupt: Box<dyn Interrupt>,
     line_control: u8,
     line_status: u8,
     modem_control: u8,
@@ -63,11 +63,11 @@ pub struct Serial {
     scratch: u8,
     baud_divisor: u16,
     in_buffer: VecDeque<u8>,
-    out: Option<Box<io::Write + Send>>,
+    out: Option<Box<dyn io::Write + Send>>,
 }
 
 impl Serial {
-    pub fn new(interrupt: Box<Interrupt>, out: Option<Box<io::Write + Send>>) -> Serial {
+    pub fn new(interrupt: Box<dyn Interrupt>, out: Option<Box<dyn io::Write + Send>>) -> Serial {
         Serial {
             interrupt_enable: 0,
             interrupt_identification: DEFAULT_INTERRUPT_IDENTIFICATION,
@@ -84,12 +84,12 @@ impl Serial {
     }
 
     /// Constructs a Serial port ready for output.
-    pub fn new_out(interrupt: Box<Interrupt>, out: Box<io::Write + Send>) -> Serial {
+    pub fn new_out(interrupt: Box<dyn Interrupt>, out: Box<dyn io::Write + Send>) -> Serial {
         Self::new(interrupt, Some(out))
     }
 
     /// Constructs a Serial port with no connected output.
-    pub fn new_sink(interrupt: Box<Interrupt>) -> Serial {
+    pub fn new_sink(interrupt: Box<dyn Interrupt>) -> Serial {
         Self::new(interrupt, None)
     }