rust: treewide: switch to the kernel `Vec` type

Now that we got the kernel `Vec` in place, convert all existing `Vec`
users to make use of it.

Reviewed-by: Alice Ryhl <[e-mail]>
Reviewed-by: Benno Lossin <[e-mail]>
Reviewed-by: Gary Guo <[e-mail]>
Signed-off-by: Danilo Krummrich <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
[ Converted `kasan_test_rust.rs` too, as discussed. - Miguel ]
Signed-off-by: Miguel Ojeda <[e-mail]>

mm/kasan/kasan_test_rust.rs

···
 /// drop the vector, and touch it.
 #[no_mangle]
 pub extern "C" fn kasan_test_rust_uaf() -> u8 {
-    let mut v: Vec<u8> = Vec::new();
+    let mut v: KVec<u8> = KVec::new();
     for _ in 0..4096 {
         v.push(0x42, GFP_KERNEL).unwrap();
     }

rust/kernel/str.rs

···
 
 //! String representations.
 
-use crate::alloc::{flags::*, vec_ext::VecExt, AllocError};
-use alloc::vec::Vec;
+use crate::alloc::{flags::*, AllocError, KVec};
 use core::fmt::{self, Write};
 use core::ops::{self, Deref, DerefMut, Index};
 
···
 /// assert_eq!(s.is_ok(), false);
 /// ```
 pub struct CString {
-    buf: Vec<u8>,
+    buf: KVec<u8>,
 }
 
 impl CString {
···
         let size = f.bytes_written();
 
         // Allocate a vector with the required number of bytes, and write to it.
-        let mut buf = <Vec<_> as VecExt<_>>::with_capacity(size, GFP_KERNEL)?;
+        let mut buf = KVec::with_capacity(size, GFP_KERNEL)?;
         // SAFETY: The buffer stored in `buf` is at least of size `size` and is valid for writes.
         let mut f = unsafe { Formatter::from_buffer(buf.as_mut_ptr(), size) };
         f.write_fmt(args)?;
···
     type Error = AllocError;
 
     fn try_from(cstr: &'a CStr) -> Result<CString, AllocError> {
-        let mut buf = Vec::new();
+        let mut buf = KVec::new();
 
-        <Vec<_> as VecExt<_>>::extend_from_slice(&mut buf, cstr.as_bytes_with_nul(), GFP_KERNEL)
-            .map_err(|_| AllocError)?;
+        buf.extend_from_slice(cstr.as_bytes_with_nul(), GFP_KERNEL)?;
 
         // INVARIANT: The `CStr` and `CString` types have the same invariants for
         // the string data, and we copied it over without changes.

rust/kernel/sync/locked_by.rs

···
 /// struct InnerDirectory {
 ///     /// The sum of the bytes used by all files.
 ///     bytes_used: u64,
-///     _files: Vec<File>,
+///     _files: KVec<File>,
 /// }
 ///
 /// struct Directory {

rust/kernel/types.rs

···
 /// # use kernel::types::ScopeGuard;
 /// fn example3(arg: bool) -> Result {
 ///     let mut vec =
-///         ScopeGuard::new_with_data(Vec::new(), |v| pr_info!("vec had {} elements\n", v.len()));
+///         ScopeGuard::new_with_data(KVec::new(), |v| pr_info!("vec had {} elements\n", v.len()));
 ///
 ///     vec.push(10u8, GFP_KERNEL)?;
 ///     if arg {

rust/kernel/uaccess.rs

···
     prelude::*,
     transmute::{AsBytes, FromBytes},
 };
-use alloc::vec::Vec;
 use core::ffi::{c_ulong, c_void};
 use core::mem::{size_of, MaybeUninit};
 
···
 /// every byte in the region.
 ///
 /// ```no_run
-/// use alloc::vec::Vec;
 /// use core::ffi::c_void;
 /// use kernel::error::Result;
 /// use kernel::uaccess::{UserPtr, UserSlice};
···
 /// fn bytes_add_one(uptr: UserPtr, len: usize) -> Result<()> {
 ///     let (read, mut write) = UserSlice::new(uptr, len).reader_writer();
 ///
-///     let mut buf = Vec::new();
+///     let mut buf = KVec::new();
 ///     read.read_all(&mut buf, GFP_KERNEL)?;
 ///
 ///     for b in &mut buf {
···
 /// Example illustrating a TOCTOU (time-of-check to time-of-use) bug.
 ///
 /// ```no_run
-/// use alloc::vec::Vec;
 /// use core::ffi::c_void;
 /// use kernel::error::{code::EINVAL, Result};
 /// use kernel::uaccess::{UserPtr, UserSlice};
···
 /// fn is_valid(uptr: UserPtr, len: usize) -> Result<bool> {
 ///     let read = UserSlice::new(uptr, len).reader();
 ///
-///     let mut buf = Vec::new();
+///     let mut buf = KVec::new();
 ///     read.read_all(&mut buf, GFP_KERNEL)?;
 ///
 ///     todo!()
 /// }
 ///
 /// /// Returns the bytes behind this user pointer if they are valid.
-/// fn get_bytes_if_valid(uptr: UserPtr, len: usize) -> Result<Vec<u8>> {
+/// fn get_bytes_if_valid(uptr: UserPtr, len: usize) -> Result<KVec<u8>> {
 ///     if !is_valid(uptr, len)? {
 ///         return Err(EINVAL);
 ///     }
 ///
 ///     let read = UserSlice::new(uptr, len).reader();
 ///
-///     let mut buf = Vec::new();
+///     let mut buf = KVec::new();
 ///     read.read_all(&mut buf, GFP_KERNEL)?;
 ///
 ///     // THIS IS A BUG! The bytes could have changed since we checked them.
···
     /// Reads the entirety of the user slice, appending it to the end of the provided buffer.
     ///
     /// Fails with [`EFAULT`] if the read happens on a bad address.
-    pub fn read_all(self, buf: &mut Vec<u8>, flags: Flags) -> Result {
+    pub fn read_all(self, buf: &mut KVec<u8>, flags: Flags) -> Result {
         self.reader().read_all(buf, flags)
     }
 
···
     /// Reads the entirety of the user slice, appending it to the end of the provided buffer.
     ///
     /// Fails with [`EFAULT`] if the read happens on a bad address.
-    pub fn read_all(mut self, buf: &mut Vec<u8>, flags: Flags) -> Result {
+    pub fn read_all(mut self, buf: &mut KVec<u8>, flags: Flags) -> Result {
         let len = self.length;
-        VecExt::<u8>::reserve(buf, len, flags)?;
+        buf.reserve(len, flags)?;
 
         // The call to `try_reserve` was successful, so the spare capacity is at least `len` bytes
         // long.

rust/macros/lib.rs

···
 /// #[pin_data]
 /// struct DriverData {
 ///     #[pin]
-///     queue: Mutex<Vec<Command>>,
+///     queue: Mutex<KVec<Command>>,
 ///     buf: KBox<[u8; 1024 * 1024]>,
 /// }
 /// ```
···
 /// #[pin_data(PinnedDrop)]
 /// struct DriverData {
 ///     #[pin]
-///     queue: Mutex<Vec<Command>>,
+///     queue: Mutex<KVec<Command>>,
 ///     buf: KBox<[u8; 1024 * 1024]>,
 ///     raw_info: *mut Info,
 /// }
···
 /// #[pin_data(PinnedDrop)]
 /// struct DriverData {
 ///     #[pin]
-///     queue: Mutex<Vec<Command>>,
+///     queue: Mutex<KVec<Command>>,
 ///     buf: KBox<[u8; 1024 * 1024]>,
 ///     raw_info: *mut Info,
 /// }

samples/rust/rust_minimal.rs

···
 }
 
 struct RustMinimal {
-    numbers: Vec<i32>,
+    numbers: KVec<i32>,
 }
 
 impl kernel::Module for RustMinimal {
···
         pr_info!("Rust minimal sample (init)\n");
         pr_info!("Am I built-in? {}\n", !cfg!(MODULE));
 
-        let mut numbers = Vec::new();
+        let mut numbers = KVec::new();
         numbers.push(72, GFP_KERNEL)?;
         numbers.push(108, GFP_KERNEL)?;
         numbers.push(200, GFP_KERNEL)?;