chore: appease clippy

- The `Default` trait can now be derived
- Lifetime elision got more sophisticated

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

src/devices/src/virtio/block/device.rs

@@ -33,23 +33,18 @@ use super::{io as block_io, Error, CONFIG_SPACE_SIZE, QUEUE_SIZES, SECTOR_SHIFT,
 use crate::virtio::{IrqTrigger, IrqType};
 
 /// Configuration options for disk caching.
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Deserialize, Serialize)]
 pub enum CacheType {
     /// Flushing mechanic will be advertised to the guest driver, but
     /// the operation will be a noop.
+    #[default]
     Unsafe,
     /// Flushing mechanic will be advertised to the guest driver and
     /// flush requests coming from the guest will be performed using
     /// `fsync`.
     Writeback,
 }
 
-impl Default for CacheType {
-    fn default() -> CacheType {
-        CacheType::Unsafe
-    }
-}
-
 #[derive(Debug, PartialEq, Eq, Deserialize, Serialize)]
 pub enum FileEngineType {
     /// Use an Async engine, based on io_uring.

src/devices/src/virtio/block/persist.rs

@@ -46,9 +46,12 @@ impl From<CacheTypeState> for CacheType {
     }
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Versionize)]
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Versionize)]
 // NOTICE: Any changes to this structure require a snapshot version bump.
 pub enum FileEngineTypeState {
+    // If the snap version does not contain the `FileEngineType`, it must have been snapshotted
+    // on a VM using the Sync backend.
+    #[default]
     Sync,
     Async,
 }
@@ -71,14 +74,6 @@ impl From<FileEngineTypeState> for FileEngineType {
     }
 }
 
-impl Default for FileEngineTypeState {
-    fn default() -> Self {
-        // If the snap version does not contain the `FileEngineType`, it must have been snapshotted
-        // on a VM using the Sync backend.
-        FileEngineTypeState::Sync
-    }
-}
-
 #[derive(Clone, Versionize)]
 // NOTICE: Any changes to this structure require a snapshot version bump.
 pub struct BlockState {

src/devices/src/virtio/queue.rs

@@ -286,7 +286,7 @@ impl Queue {
     }
 
     /// Pop the first available descriptor chain from the avail ring.
-    pub fn pop<'a, 'b>(&'a mut self, mem: &'b GuestMemoryMmap) -> Option<DescriptorChain<'b>> {
+    pub fn pop<'b>(&mut self, mem: &'b GuestMemoryMmap) -> Option<DescriptorChain<'b>> {
         let len = self.len(mem);
         // The number of descriptor chain heads to process should always
         // be smaller or equal to the queue size, as the driver should
@@ -310,8 +310,8 @@ impl Queue {
 
     /// Try to pop the first available descriptor chain from the avail ring.
     /// If no descriptor is available, enable notifications.
-    pub fn pop_or_enable_notification<'a, 'b>(
-        &'a mut self,
+    pub fn pop_or_enable_notification<'b>(
+        &mut self,
         mem: &'b GuestMemoryMmap,
     ) -> Option<DescriptorChain<'b>> {
         if !self.uses_notif_suppression {
@@ -330,10 +330,7 @@ impl Queue {
     /// # Important
     /// This is an internal method that ASSUMES THAT THERE ARE AVAILABLE DESCRIPTORS. Otherwise it
     /// will retrieve a descriptor that contains garbage data (obsolete/empty).
-    fn do_pop_unchecked<'a, 'b>(
-        &'a mut self,
-        mem: &'b GuestMemoryMmap,
-    ) -> Option<DescriptorChain<'b>> {
+    fn do_pop_unchecked<'b>(&mut self, mem: &'b GuestMemoryMmap) -> Option<DescriptorChain<'b>> {
         // This fence ensures all subsequent reads see the updated driver writes.
         fence(Ordering::Acquire);
 

src/dumbo/src/tcp/handler.rs

@@ -507,8 +507,8 @@ mod tests {
     use crate::pdu::bytes::NetworkBytesMut;
     use crate::tcp::tests::mock_callback;
 
-    fn inner_tcp_mut<'a, 'b, T: NetworkBytesMut>(
-        p: &'a mut IPv4Packet<'b, T>,
+    fn inner_tcp_mut<'a, T: NetworkBytesMut>(
+        p: &'a mut IPv4Packet<'_, T>,
     ) -> TcpSegment<'a, &'a mut [u8]> {
         TcpSegment::from_bytes(p.payload_mut(), None).unwrap()
     }

src/mmds/src/data_store.rs

@@ -19,18 +19,13 @@ pub struct Mmds {
 }
 
 /// MMDS version.
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Deserialize, Serialize)]
 pub enum MmdsVersion {
+    #[default]
     V1,
     V2,
 }
 
-impl Default for MmdsVersion {
-    fn default() -> Self {
-        MmdsVersion::V1
-    }
-}
-
 impl Display for MmdsVersion {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {

src/vmm/src/vmm_config/instance_info.rs

@@ -5,22 +5,17 @@ use std::fmt::{self, Display, Formatter};
 use serde::{ser, Serialize};
 
 /// Enumerates microVM runtime states.
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
 pub enum VmState {
     /// Vm not started (yet)
+    #[default]
     NotStarted,
     /// Vm is Paused
     Paused,
     /// Vm is running
     Running,
 }
 
-impl Default for VmState {
-    fn default() -> VmState {
-        VmState::NotStarted
-    }
-}
-
 impl Display for VmState {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match *self {

src/vmm/src/vmm_config/logger.rs

@@ -12,13 +12,14 @@ use super::{open_file_nonblock, FcLineWriter};
 use crate::vmm_config::instance_info::InstanceInfo;
 
 /// Enum used for setting the log level.
-#[derive(Clone, Debug, PartialEq, Eq, Deserialize, Serialize)]
+#[derive(Clone, Debug, Default, PartialEq, Eq, Deserialize, Serialize)]
 pub enum LoggerLevel {
     /// When the level is set to `Error`, the logger will only contain entries
     /// that come from the `error` macro.
     Error,
     /// When the level is set to `Warning`, the logger will only contain entries
     /// that come from the `error` and `warn` macros.
+    #[default]
     Warning,
     /// When the level is set to `Info`, the logger will only contain entries
     /// that come from the `error`, `warn` and `info` macros.
@@ -41,12 +42,6 @@ impl LoggerLevel {
     }
 }
 
-impl Default for LoggerLevel {
-    fn default() -> LoggerLevel {
-        LoggerLevel::Warning
-    }
-}
-
 impl From<LoggerLevel> for LevelFilter {
     fn from(logger_level: LoggerLevel) -> Self {
         match logger_level {

src/vmm/src/vmm_config/machine_config.rs

@@ -238,7 +238,7 @@ where
 
 /// Template types available for configuring the CPU features that map
 /// to EC2 instances.
-#[derive(Clone, Copy, Debug, Deserialize, Eq, PartialEq, Serialize, Versionize)]
+#[derive(Clone, Copy, Debug, Default, Deserialize, Eq, PartialEq, Serialize, Versionize)]
 pub enum CpuFeaturesTemplate {
     /// C3 Template.
     C3,
@@ -247,6 +247,7 @@ pub enum CpuFeaturesTemplate {
     /// T2S Template.
     T2S,
     /// No CPU template is used.
+    #[default]
     None,
     /// T2CL Template.
     T2CL,
@@ -274,12 +275,6 @@ impl fmt::Display for CpuFeaturesTemplate {
     }
 }
 
-impl Default for CpuFeaturesTemplate {
-    fn default() -> Self {
-        CpuFeaturesTemplate::None
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;

src/vmm/src/vmm_config/snapshot.rs

@@ -9,20 +9,15 @@ use serde::{Deserialize, Serialize};
 
 /// The snapshot type options that are available when
 /// creating a new snapshot.
-#[derive(Debug, PartialEq, Eq, Deserialize, Serialize)]
+#[derive(Debug, Default, PartialEq, Eq, Deserialize, Serialize)]
 pub enum SnapshotType {
     /// Diff snapshot.
     Diff,
     /// Full snapshot.
+    #[default]
     Full,
 }
 
-impl Default for SnapshotType {
-    fn default() -> Self {
-        SnapshotType::Full
-    }
-}
-
 /// Specifies the method through which guest memory will get populated when
 /// resuming from a snapshot:
 /// 1) A file that contains the guest memory to be loaded,