Re: [PATCH v5 3/6] rust: bitmap: rename IdPool::new() to with_capacity()

[Yury Norov <yury.norov@gmail.com>]

On Wed, Nov 12, 2025 at 12:47:21PM +0000, Alice Ryhl wrote:
> We want to change ::new() to take no parameters and produce a pool that
> is as large as possible while also being inline because that is the
> constructor that Rust Binder actually needs.
> 
> However, to avoid complications in examples, we still need the current
> constructor. So rename it to with_capacity(), which is the idiomatic
> Rust name for this kind constructor.
> 
> Reviewed-by: Burak Emir <bqe@google.com>
> Signed-off-by: Alice Ryhl <aliceryhl@google.com>
> ---
>  rust/kernel/id_pool.rs | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/rust/kernel/id_pool.rs b/rust/kernel/id_pool.rs
> index 8f68b45a3da1f62dd0d010480837de49b9a343ba..90836b05c6155f98ab8393c8291749f408dbd4da 100644
> --- a/rust/kernel/id_pool.rs
> +++ b/rust/kernel/id_pool.rs
> @@ -26,7 +26,7 @@
>  /// use kernel::alloc::{AllocError, flags::GFP_KERNEL};
>  /// use kernel::id_pool::IdPool;
>  ///
> -/// let mut pool = IdPool::new(64, GFP_KERNEL)?;
> +/// let mut pool = IdPool::with_capacity(64, GFP_KERNEL)?;
>  /// for i in 0..64 {
>  ///     assert_eq!(i, pool.acquire_next_id(i).ok_or(ENOSPC)?);
>  /// }
> @@ -93,14 +93,14 @@ pub fn realloc(&self, flags: Flags) -> Result<PoolResizer, AllocError> {
>  }
>  
>  impl IdPool {
> -    /// Constructs a new [`IdPool`].
> +    /// Constructs a new [`IdPool`] with space for a specific number of bits.
>      ///
>      /// A capacity below [`MAX_INLINE_LEN`] is adjusted to [`MAX_INLINE_LEN`].
>      ///
>      /// [`MAX_INLINE_LEN`]: BitmapVec::MAX_INLINE_LEN
>      #[inline]
> -    pub fn new(num_ids: usize, flags: Flags) -> Result<Self, AllocError> {
> -        let num_ids = usize::max(num_ids, BitmapVec::MAX_INLINE_LEN);
> +    pub fn with_capacity(num_ids: usize, flags: Flags) -> Result<Self, AllocError> {
> +        let num_ids = usize::max(num_ids, BITS_PER_LONG);

           let num_ids = usize::max(num_ids, MAX_INLINE_LEN);

>          let map = BitmapVec::new(num_ids, flags)?;
>          Ok(Self { map })
>      }
> @@ -123,7 +123,7 @@ pub fn capacity(&self) -> usize {
>      /// use kernel::alloc::{AllocError, flags::GFP_KERNEL};
>      /// use kernel::id_pool::{ReallocRequest, IdPool};
>      ///
> -    /// let mut pool = IdPool::new(1024, GFP_KERNEL)?;
> +    /// let mut pool = IdPool::with_capacity(1024, GFP_KERNEL)?;
>      /// let alloc_request = pool.shrink_request().ok_or(AllocError)?;
>      /// let resizer = alloc_request.realloc(GFP_KERNEL)?;
>      /// pool.shrink(resizer);
> 
> -- 
> 2.51.2.1041.gc1ab5b90ca-goog