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Message-ID: <2024100505-aftermath-glue-7e61@gregkh>
Date: Sat, 5 Oct 2024 09:40:53 +0200
From: Greg KH <gregkh@...uxfoundation.org>
To: Gary Guo <gary@...yguo.net>
Cc: Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>,
Boqun Feng <boqun.feng@...il.com>,
Björn Roy Baron <bjorn3_gh@...tonmail.com>,
Benno Lossin <benno.lossin@...ton.me>,
Andreas Hindborg <a.hindborg@...nel.org>,
Alice Ryhl <aliceryhl@...gle.com>, Trevor Gross <tmgross@...ch.edu>,
Martin Rodriguez Reboredo <yakoyoku@...il.com>,
Will Deacon <will@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Mark Rutland <mark.rutland@....com>,
Dirk Behme <dirk.behme@...bosch.com>, linux-kernel@...r.kernel.org,
rust-for-linux@...r.kernel.org
Subject: Re: [PATCH 1/3] rust: implement `kernel::sync::Refcount`
On Fri, Oct 04, 2024 at 04:52:22PM +0100, Gary Guo wrote:
> This is a wrapping layer of `include/linux/refcount.h`. Currently only
> the most basic operations (read/set/inc/dec/dec_and_test) are implemented,
> additional methods can be implemented when they are needed.
>
> Currently the kernel refcount has already been used in `Arc`, however it
> calls into FFI directly.
>
> Cc: Will Deacon <will@...nel.org>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Boqun Feng <boqun.feng@...il.com>
> Cc: Mark Rutland <mark.rutland@....com>
> Signed-off-by: Gary Guo <gary@...yguo.net>
> ---
> rust/helpers/refcount.c | 15 ++++++
> rust/kernel/sync.rs | 2 +
> rust/kernel/sync/refcount.rs | 94 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 111 insertions(+)
> create mode 100644 rust/kernel/sync/refcount.rs
>
> diff --git a/rust/helpers/refcount.c b/rust/helpers/refcount.c
> index f47afc148ec3..39649443426b 100644
> --- a/rust/helpers/refcount.c
> +++ b/rust/helpers/refcount.c
> @@ -8,11 +8,26 @@ refcount_t rust_helper_REFCOUNT_INIT(int n)
> return (refcount_t)REFCOUNT_INIT(n);
> }
>
> +unsigned int rust_helper_refcount_read(refcount_t *r)
> +{
> + return refcount_read(r);
> +}
Reading a refcount is almost always a wrong thing to do (it can change
right after you read it), and I don't see any of the later patches in
this series use this call, so can you just drop this?
thanks,
greg k-h
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