Re: [PATCH v7 22/26] rust: alloc: implement `Cmalloc` in module allocator_test

[Danilo Krummrich <dakr@kernel.org>]

On Sat, Sep 28, 2024 at 08:35:52PM +0100, Gary Guo wrote:
> On Thu, 12 Sep 2024 00:52:58 +0200
> Danilo Krummrich <dakr@kernel.org> wrote:
> 
> > So far the kernel's `Box` and `Vec` types can't be used by userspace
> > test cases, since all users of those types (e.g. `CString`) use kernel
> > allocators for instantiation.
> > 
> > In order to allow userspace test cases to make use of such types as
> > well, implement the `Cmalloc` allocator within the allocator_test module
> > and type alias all kernel allocators to `Cmalloc`. The `Cmalloc`
> > allocator uses libc's realloc() function as allocator backend.
> 
> I think this needs an explaination of why it needs a complex
> implementation instead of just using aligned_alloc and free.

The reason basically is that there's no `aligned_realloc` in libc. Anyways, it's
gonna simplified by the introduction of `old_layout`.

> 
> > 
> > Signed-off-by: Danilo Krummrich <dakr@kernel.org>
> > ---
> >  rust/kernel/alloc/allocator_test.rs | 193 +++++++++++++++++++++++++++-
> >  1 file changed, 186 insertions(+), 7 deletions(-)
>