[PATCH v3] rust: error: modify `from_errno` to use `try_from_errno`

[Daniel Sedlak <daniel@sedlak.dev>]

Modify the from_errno function to use try_from_errno to
reduce code duplication while still maintaining all existing
behavior and error handling and also reduces unsafe code.

Link: https://github.com/Rust-for-Linux/linux/issues/1125
Suggested-by:  Miguel Ojeda <ojeda@kernel.org>
Co-developed-by: Guilherme Augusto Martins da Silva <guilhermev2huehue@gmail.com>
Signed-off-by: Guilherme Augusto Martins da Silva <guilhermev2huehue@gmail.com>
Signed-off-by: Daniel Sedlak <daniel@sedlak.dev>
---
 rust/kernel/error.rs | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
index 52c502432447..236b3e4719e6 100644
--- a/rust/kernel/error.rs
+++ b/rust/kernel/error.rs
@@ -100,20 +100,17 @@ impl Error {
     ///
     /// It is a bug to pass an out-of-range `errno`. `EINVAL` would
     /// be returned in such a case.
-    pub fn from_errno(errno: crate::ffi::c_int) -> Error {
-        if errno < -(bindings::MAX_ERRNO as i32) || errno >= 0 {
+    pub fn from_errno(errno: core::ffi::c_int) -> Error {
+        if let Some(error) = Self::try_from_errno(errno) {
+            error
+        } else {
             // TODO: Make it a `WARN_ONCE` once available.
             crate::pr_warn!(
                 "attempted to create `Error` with out of range `errno`: {}",
                 errno
             );
-            return code::EINVAL;
+            code::EINVAL
         }
-
-        // INVARIANT: The check above ensures the type invariant
-        // will hold.
-        // SAFETY: `errno` is checked above to be in a valid range.
-        unsafe { Error::from_errno_unchecked(errno) }
     }
 
     /// Creates an [`Error`] from a kernel error code.
-- 
2.47.0