refactor: remove std::result::Result usage

We have a convention of not referring to Result
type with full path since it is implicitly added to
all namespaces.
Additionally remove Result type redefinitions as we
don't allow this.

Signed-off-by: Egor Lazarchuk <[email protected]>

Author: ShadowCurse

src/firecracker/src/api_server/parsed_request.rs

@@ -157,7 +157,7 @@ impl ParsedRequest {
     }
 
     pub(crate) fn convert_to_response(
-        request_outcome: &std::result::Result<VmmData, VmmActionError>,
+        request_outcome: &Result<VmmData, VmmActionError>,
     ) -> Response {
         match request_outcome {
             Ok(vmm_data) => match vmm_data {

src/jailer/src/cgroup.rs

@@ -522,7 +522,7 @@ pub mod test_util {
         pub fn create_file_with_contents<P: AsRef<Path> + Debug>(
             filename: P,
             contents: &str,
-        ) -> std::result::Result<(), std::io::Error> {
+        ) -> Result<(), std::io::Error> {
             let mut file = OpenOptions::new()
                 .read(true)
                 .write(true)
@@ -534,7 +534,7 @@ pub mod test_util {
             Ok(())
         }
 
-        pub fn new() -> std::result::Result<MockCgroupFs, std::io::Error> {
+        pub fn new() -> Result<MockCgroupFs, std::io::Error> {
             let mock_jailer_dir = TempDir::new().unwrap();
             let mock_proc_mounts = mock_jailer_dir.as_path().join("proc/mounts");
             let mock_sys_cgroups = mock_jailer_dir.as_path().join("sys_cgroup");
@@ -557,7 +557,7 @@ pub mod test_util {
 
         // Populate the mocked proc/mounts file with cgroupv2 entries
         // Also create a directory structure that simulates cgroupsv2 layout
-        pub fn add_v2_mounts(&mut self) -> std::result::Result<(), std::io::Error> {
+        pub fn add_v2_mounts(&mut self) -> Result<(), std::io::Error> {
             writeln!(
                 self.mounts_file,
                 "cgroupv2 {}/unified cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate 0 0",
@@ -574,7 +574,7 @@ pub mod test_util {
         }
 
         // Populate the mocked proc/mounts file with cgroupv1 entries
-        pub fn add_v1_mounts(&mut self) -> std::result::Result<(), std::io::Error> {
+        pub fn add_v1_mounts(&mut self) -> Result<(), std::io::Error> {
             let controllers = vec![
                 "memory",
                 "net_cls,net_prio",
@@ -610,7 +610,7 @@ mod tests {
     use crate::cgroup::test_util::MockCgroupFs;
 
     // Utility function to read the first line in a file
-    fn read_first_line<P>(filename: P) -> std::result::Result<String, std::io::Error>
+    fn read_first_line<P>(filename: P) -> Result<String, std::io::Error>
     where
         P: AsRef<Path> + Debug,
     {

src/vmm/src/device_manager/mod.rs

@@ -471,7 +471,7 @@ impl<'a> Persist<'a> for DeviceManager {
     fn restore(
         constructor_args: Self::ConstructorArgs,
         state: &Self::State,
-    ) -> std::result::Result<Self, Self::Error> {
+    ) -> Result<Self, Self::Error> {
         // Setup legacy devices in case of x86
         #[cfg(target_arch = "x86_64")]
         let legacy_devices = Self::create_legacy_devices(

src/vmm/src/device_manager/pci_mngr.rs

@@ -396,7 +396,7 @@ impl<'a> Persist<'a> for PciDevices {
     fn restore(
         constructor_args: Self::ConstructorArgs,
         state: &Self::State,
-    ) -> std::result::Result<Self, Self::Error> {
+    ) -> Result<Self, Self::Error> {
         let mem = constructor_args.mem;
         let mut pci_devices = PciDevices::new();
         if !state.pci_enabled {

src/vmm/src/device_manager/persist.rs

@@ -193,7 +193,7 @@ impl<'a> Persist<'a> for ACPIDeviceManager {
     fn restore(
         constructor_args: Self::ConstructorArgs,
         state: &Self::State,
-    ) -> std::result::Result<Self, Self::Error> {
+    ) -> Result<Self, Self::Error> {
         let mut dev_manager = ACPIDeviceManager::new();
         if let Some(vmgenid_args) = &state.vmgenid {
             let vmgenid = VmGenId::restore(

src/vmm/src/devices/acpi/vmgenid.rs

@@ -151,7 +151,7 @@ impl<'a> Persist<'a> for VmGenId {
     fn restore(
         constructor_args: Self::ConstructorArgs,
         state: &Self::State,
-    ) -> std::result::Result<Self, Self::Error> {
+    ) -> Result<Self, Self::Error> {
         Self::from_parts(GuestAddress(state.addr), state.gsi, constructor_args.mem)
     }
 }

src/vmm/src/devices/virtio/transport/pci/device.rs

@@ -255,7 +255,6 @@ pub enum VirtioPciDeviceError {
     /// Error creating MSI configuration: {0}
     Msi(#[from] InterruptError),
 }
-pub type Result<T> = std::result::Result<T, VirtioPciDeviceError>;
 
 pub struct VirtioPciDevice {
     id: String,
@@ -370,7 +369,7 @@ impl VirtioPciDevice {
         device: Arc<Mutex<dyn VirtioDevice>>,
         msix_vectors: Arc<MsixVectorGroup>,
         pci_device_bdf: u32,
-    ) -> Result<Self> {
+    ) -> Result<Self, VirtioPciDeviceError> {
         let num_queues = device.lock().expect("Poisoned lock").queues().len();
 
         let msix_config = Arc::new(Mutex::new(MsixConfig::new(
@@ -419,7 +418,7 @@ impl VirtioPciDevice {
         vm: &Arc<Vm>,
         device: Arc<Mutex<dyn VirtioDevice>>,
         state: VirtioPciDeviceState,
-    ) -> Result<Self> {
+    ) -> Result<Self, VirtioPciDeviceError> {
         let msix_config =
             MsixConfig::from_state(state.msix_state, vm.clone(), state.pci_device_bdf.into())?;
         let vectors = msix_config.vectors.clone();
@@ -603,7 +602,7 @@ impl VirtioPciDevice {
     }
 
     /// Register the IoEvent notification for a VirtIO device
-    pub fn register_notification_ioevent(&self, vm: &Vm) -> std::result::Result<(), errno::Error> {
+    pub fn register_notification_ioevent(&self, vm: &Vm) -> Result<(), errno::Error> {
         let bar_addr = self.config_bar_addr();
         for (i, queue_evt) in self
             .device
@@ -676,7 +675,7 @@ impl VirtioInterruptMsix {
 }
 
 impl VirtioInterrupt for VirtioInterruptMsix {
-    fn trigger(&self, int_type: VirtioInterruptType) -> std::result::Result<(), InterruptError> {
+    fn trigger(&self, int_type: VirtioInterruptType) -> Result<(), InterruptError> {
         let vector = match int_type {
             VirtioInterruptType::Config => self.config_vector.load(Ordering::Acquire),
             VirtioInterruptType::Queue(queue_index) => *self
@@ -783,7 +782,7 @@ impl PciDevice for VirtioPciDevice {
         self.configuration.detect_bar_reprogramming(reg_idx, data)
     }
 
-    fn move_bar(&mut self, old_base: u64, new_base: u64) -> std::result::Result<(), anyhow::Error> {
+    fn move_bar(&mut self, old_base: u64, new_base: u64) -> Result<(), anyhow::Error> {
         // We only update our idea of the bar in order to support free_bars() above.
         // The majority of the reallocation is done inside DeviceManager.
         if self.bar_address == old_base {

src/vmm/src/dumbo/pdu/arp.rs

@@ -10,7 +10,6 @@
 use std::convert::From;
 use std::fmt::Debug;
 use std::net::Ipv4Addr;
-use std::result::Result;
 
 use super::bytes::{InnerBytes, NetworkBytes, NetworkBytesMut};
 use super::ethernet::{self, ETHERTYPE_IPV4};

src/vmm/src/dumbo/pdu/ethernet.rs

@@ -5,7 +5,6 @@
 //! 802.1Q tags.
 
 use std::fmt::Debug;
-use std::result::Result;
 
 use super::Incomplete;
 use super::bytes::{InnerBytes, NetworkBytes, NetworkBytesMut};

src/vmm/src/dumbo/pdu/ipv4.rs

@@ -10,7 +10,6 @@
 use std::convert::From;
 use std::fmt::Debug;
 use std::net::Ipv4Addr;
-use std::result::Result;
 
 use crate::dumbo::pdu::bytes::{InnerBytes, NetworkBytes, NetworkBytesMut};
 use crate::dumbo::pdu::{Incomplete, ethernet};