rust: kernel: use the new try_* methods

In preparation for enabling `no_global_oom_handling` for `alloc`,
we need to stop using methods that will disappear when enabling
the configuration option. Instead, we use the new methods
we just added.

Signed-off-by: Miguel Ojeda <[email protected]>

Author: ojeda

rust/kernel/io_buffer.rs

@@ -30,8 +30,7 @@ pub trait IoBufferReader {
     /// Returns `EFAULT` if the address does not currently point to mapped, readable memory.
     fn read_all(&mut self) -> Result<Vec<u8>> {
         let mut data = Vec::<u8>::new();
-        data.try_reserve_exact(self.len())?;
-        data.resize(self.len(), 0);
+        data.try_resize(self.len(), 0)?;
 
         // SAFETY: The output buffer is valid as we just allocated it.
         unsafe { self.read_raw(data.as_mut_ptr(), data.len())? };

rust/kernel/module_param.rs

@@ -476,8 +476,7 @@ impl ModuleParam for StringParam {
         arg.and_then(|arg| {
             if slab_available {
                 let mut vec = alloc::vec::Vec::new();
-                vec.try_reserve_exact(arg.len()).ok()?;
-                vec.extend_from_slice(arg);
+                vec.try_extend_from_slice(arg).ok()?;
                 Some(StringParam::Owned(vec))
             } else {
                 Some(StringParam::Ref(arg))

rust/kernel/sysctl.rs

@@ -156,7 +156,7 @@ impl<T: SysctlStorage> Sysctl<T> {
             },
             unsafe { mem::zeroed() },
         ]
-        .into_boxed_slice();
+        .try_into_boxed_slice()?;
 
         let result = unsafe { bindings::register_sysctl(path.as_char_ptr(), table.as_mut_ptr()) };
         if result.is_null() {

samples/rust/rust_minimal.rs

@@ -25,7 +25,7 @@ impl KernelModule for RustMinimal {
         pr_info!("Am I built-in? {}\n", !cfg!(MODULE));
 
         Ok(RustMinimal {
-            message: "on the heap!".to_owned(),
+            message: "on the heap!".try_to_owned()?,
         })
     }
 }