Re: [PATCH v4 3/6] rust: bitmap: rename IdPool::new to with_capacity

Burak Emir
2025-11-10T14:13:07Z

On Mon, Nov 10, 2025 at 2:06 PM Alice Ryhl <aliceryhl@google.com> 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 | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/rust/kernel/id_pool.rs b/rust/kernel/id_pool.rs
> index a41a3404213ca92d53b14c80101afff6ac8c416e..5942f678db015e902fa482eb64c38512a468e449 100644
> --- a/rust/kernel/id_pool.rs
> +++ b/rust/kernel/id_pool.rs
> @@ -28,7 +28,7 @@
> /// 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)?);
> /// }
> @@ -95,14 +95,14 @@ 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 [`BITS_PER_LONG`] is adjusted to
> - /// [`BITS_PER_LONG`].
> + /// A capacity below [`NO_ALLOC_MAX_LEN`] is adjusted to
> + /// [`NO_ALLOC_MAX_LEN`].
> ///
> - /// [`BITS_PER_LONG`]: srctree/include/asm-generic/bitsperlong.h
> + /// [`NO_ALLOC_MAX_LEN`]: BitmapVec::NO_ALLOC_MAX_LEN
> #[inline]
> - pub fn new(num_ids: usize, flags: Flags) -> Result<Self, AllocError> {
> + pub fn with_capacity(num_ids: usize, flags: Flags) -> Result<Self, AllocError> {
> let num_ids = core::cmp::max(num_ids, BITS_PER_LONG);
> let map = BitmapVec::new(num_ids, flags)?;
> Ok(Self { map })
> @@ -126,7 +126,7 @@ 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
>