Merge pull request #131 from wedsonaf/result

Add default value for the first parameter of `KernelResult`.

Author: ojeda

rust/kernel/chrdev.rs

@@ -78,7 +78,7 @@ impl<const N: usize> Registration<{ N }> {
     /// Registers a character device.
     ///
     /// You may call this once per device type, up to `N` times.
-    pub fn register<T: file_operations::FileOperations>(self: Pin<&mut Self>) -> KernelResult<()> {
+    pub fn register<T: file_operations::FileOperations>(self: Pin<&mut Self>) -> KernelResult {
         // SAFETY: We must ensure that we never move out of `this`.
         let this = unsafe { self.get_unchecked_mut() };
         if this.inner.is_none() {

rust/kernel/error.rs

@@ -92,9 +92,9 @@ impl From<TryReserveError> for Error {
 /// its error type.
 ///
 /// Note that even if a function does not return anything when it succeeds,
-/// it should still be modeled as returning a `KernelResult<()>` rather than
+/// it should still be modeled as returning a `KernelResult` rather than
 /// just an [`Error`].
-pub type KernelResult<T> = Result<T, Error>;
+pub type KernelResult<T = ()> = Result<T, Error>;
 
 impl From<AllocError> for Error {
     fn from(_: AllocError) -> Error {

rust/kernel/file_operations.rs

@@ -439,7 +439,7 @@ pub trait FileOperations: Sync + Sized {
     /// Reads data from this file to userspace.
     ///
     /// Corresponds to the `read` function pointer in `struct file_operations`.
-    fn read(&self, _file: &File, _data: &mut UserSlicePtrWriter, _offset: u64) -> KernelResult<()> {
+    fn read(&self, _file: &File, _data: &mut UserSlicePtrWriter, _offset: u64) -> KernelResult {
         Err(Error::EINVAL)
     }
 

rust/kernel/miscdev.rs

@@ -51,7 +51,7 @@ impl Registration {
         self: Pin<&mut Self>,
         name: CStr<'static>,
         minor: Option<i32>,
-    ) -> KernelResult<()> {
+    ) -> KernelResult {
         // SAFETY: We must ensure that we never move out of `this`.
         let this = unsafe { self.get_unchecked_mut() };
         if this.mdev.is_some() {

rust/kernel/random.rs

@@ -12,7 +12,7 @@ use crate::{bindings, c_types, error};
 ///
 /// Ensures that the CSPRNG has been seeded before generating any random bytes,
 /// and will block until it is ready.
-pub fn getrandom(dest: &mut [u8]) -> error::KernelResult<()> {
+pub fn getrandom(dest: &mut [u8]) -> error::KernelResult {
     let res = unsafe { bindings::wait_for_random_bytes() };
     if res != 0 {
         return Err(error::Error::from_kernel_errno(res));
@@ -30,7 +30,7 @@ pub fn getrandom(dest: &mut [u8]) -> error::KernelResult<()> {
 /// Fills a byte slice with random bytes generated from the kernel's CSPRNG.
 ///
 /// If the CSPRNG is not yet seeded, returns an `Err(EAGAIN)` immediately.
-pub fn getrandom_nonblock(dest: &mut [u8]) -> error::KernelResult<()> {
+pub fn getrandom_nonblock(dest: &mut [u8]) -> error::KernelResult {
     if !unsafe { bindings::rng_is_initialized() } {
         return Err(error::Error::EAGAIN);
     }

rust/kernel/sysctl.rs

@@ -21,10 +21,10 @@ use crate::user_ptr::{UserSlicePtr, UserSlicePtrWriter};
 /// Sysctl storage.
 pub trait SysctlStorage: Sync {
     /// Writes a byte slice.
-    fn store_value(&self, data: &[u8]) -> (usize, error::KernelResult<()>);
+    fn store_value(&self, data: &[u8]) -> (usize, error::KernelResult);
 
     /// Reads via a [`UserSlicePtrWriter`].
-    fn read_value(&self, data: &mut UserSlicePtrWriter) -> (usize, error::KernelResult<()>);
+    fn read_value(&self, data: &mut UserSlicePtrWriter) -> (usize, error::KernelResult);
 }
 
 fn trim_whitespace(mut data: &[u8]) -> &[u8] {
@@ -45,17 +45,17 @@ impl<T> SysctlStorage for &T
 where
     T: SysctlStorage,
 {
-    fn store_value(&self, data: &[u8]) -> (usize, error::KernelResult<()>) {
+    fn store_value(&self, data: &[u8]) -> (usize, error::KernelResult) {
         (*self).store_value(data)
     }
 
-    fn read_value(&self, data: &mut UserSlicePtrWriter) -> (usize, error::KernelResult<()>) {
+    fn read_value(&self, data: &mut UserSlicePtrWriter) -> (usize, error::KernelResult) {
         (*self).read_value(data)
     }
 }
 
 impl SysctlStorage for atomic::AtomicBool {
-    fn store_value(&self, data: &[u8]) -> (usize, error::KernelResult<()>) {
+    fn store_value(&self, data: &[u8]) -> (usize, error::KernelResult) {
         let result = match trim_whitespace(data) {
             b"0" => {
                 self.store(false, atomic::Ordering::Relaxed);
@@ -70,7 +70,7 @@ impl SysctlStorage for atomic::AtomicBool {
         (data.len(), result)
     }
 
-    fn read_value(&self, data: &mut UserSlicePtrWriter) -> (usize, error::KernelResult<()>) {
+    fn read_value(&self, data: &mut UserSlicePtrWriter) -> (usize, error::KernelResult) {
         let value = if self.load(atomic::Ordering::Relaxed) {
             b"1\n"
         } else {