From: Boqun Feng <boqun.feng@gmail.com>
To: Gary Guo <gary@garyguo.net>
Cc: "Asahi Lina" <lina@asahilina.net>,
"Miguel Ojeda" <ojeda@kernel.org>,
"Alex Gaynor" <alex.gaynor@gmail.com>,
"Wedson Almeida Filho" <wedsonaf@gmail.com>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
"Will Deacon" <will@kernel.org>,
"Robin Murphy" <robin.murphy@arm.com>,
"Joerg Roedel" <joro@8bytes.org>,
"Hector Martin" <marcan@marcan.st>,
"Sven Peter" <sven@svenpeter.dev>,
"Arnd Bergmann" <arnd@arndb.de>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"Alyssa Rosenzweig" <alyssa@rosenzweig.io>,
"Neal Gompa" <neal@gompa.dev>,
rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
asahi@lists.linux.dev
Subject: Re: [PATCH 5/5] rust: device: Add a stub abstraction for devices
Date: Mon, 13 Mar 2023 11:05:04 -0700 [thread overview]
Message-ID: <ZA9l0EHCRRr/myoq@boqun-archlinux> (raw)
In-Reply-To: <20230313175202.300bb1f4.gary@garyguo.net>
On Mon, Mar 13, 2023 at 05:52:02PM +0000, Gary Guo wrote:
[...]
> > diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
> > index 9be021e393ca..e57da622d817 100644
> > --- a/rust/kernel/device.rs
> > +++ b/rust/kernel/device.rs
> > @@ -4,7 +4,7 @@
> > //!
> > //! C header: [`include/linux/device.h`](../../../../include/linux/device.h)
> >
> > -use crate::bindings;
> > +use crate::{bindings, str::CStr};
> >
> > /// A raw device.
> > ///
> > @@ -20,4 +20,78 @@ use crate::bindings;
> > pub unsafe trait RawDevice {
> > /// Returns the raw `struct device` related to `self`.
> > fn raw_device(&self) -> *mut bindings::device;
> > +
> > + /// Returns the name of the device.
> > + fn name(&self) -> &CStr {
> > + let ptr = self.raw_device();
> > +
> > + // SAFETY: `ptr` is valid because `self` keeps it alive.
> > + let name = unsafe { bindings::dev_name(ptr) };
> > +
> > + // SAFETY: The name of the device remains valid while it is alive (because the device is
> > + // never renamed, per the safety requirement of this trait). This is guaranteed to be the
> > + // case because the reference to `self` outlives the one of the returned `CStr` (enforced
> > + // by the compiler because of their lifetimes).
> > + unsafe { CStr::from_char_ptr(name) }
> > + }
> > +}
> > +
> > +/// A ref-counted device.
> > +///
> > +/// # Invariants
> > +///
> > +/// `ptr` is valid, non-null, and has a non-zero reference count. One of the references is owned by
> > +/// `self`, and will be decremented when `self` is dropped.
> > +pub struct Device {
> > + pub(crate) ptr: *mut bindings::device,
> > +}
> > +
>
> Shouldn't this be
>
> #[repr(transparent)]
> pub struct Device(Opaque<bindings::device>);
>
> ?
I have the same feeling, for `task_struct`, we have
#[repr(transparent)]
pub struct Task(pub(crate) UnsafeCell<bindings::task_struct>);
and
pub struct TaskRef<'a> {
task: &'a Task,
_not_send: PhantomData<*mut ()>,
}
I wonder whether we should do the similar for `Device`, meaning `Device`
is just a tranparent representation for `struct device` and another
type (say, `DeviceRef`) is introduced as the reference type, or we can
just use `ARef`.
Regards,
Boqun
>
> Best,
> Gary
prev parent reply other threads:[~2023-03-13 18:06 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-24 10:53 [PATCH 0/5] rust: Add io_pgtable and RTKit abstractions Asahi Lina
2023-02-24 10:53 ` [PATCH 1/5] rust: Add a Sealed trait Asahi Lina
2023-02-24 10:53 ` [PATCH 2/5] rust: device: Add a minimal RawDevice trait Asahi Lina
2023-02-24 11:23 ` Greg Kroah-Hartman
2023-02-24 13:15 ` Asahi Lina
2023-02-24 14:11 ` Greg Kroah-Hartman
2023-02-24 14:19 ` Greg Kroah-Hartman
2023-02-24 14:44 ` Asahi Lina
2023-02-24 15:25 ` Greg Kroah-Hartman
2023-02-24 15:45 ` Asahi Lina
2023-02-25 17:07 ` alyssa
2023-02-24 14:32 ` Robin Murphy
2023-02-24 14:48 ` Asahi Lina
2023-02-24 15:14 ` Robin Murphy
2023-02-24 16:23 ` Asahi Lina
2023-02-24 19:22 ` Miguel Ojeda
2023-03-05 6:52 ` Wedson Almeida Filho
2023-02-24 15:32 ` Greg Kroah-Hartman
2023-02-24 18:52 ` Robin Murphy
2023-02-25 7:00 ` Greg Kroah-Hartman
2023-02-24 14:43 ` Asahi Lina
2023-02-24 15:24 ` Greg Kroah-Hartman
2023-02-24 15:42 ` Asahi Lina
2023-02-24 10:53 ` [PATCH 3/5] rust: io_pgtable: Add io_pgtable abstraction Asahi Lina
2023-02-24 10:53 ` [PATCH 4/5] rust: soc: apple: rtkit: Add Apple RTKit abstraction Asahi Lina
2023-02-24 10:53 ` [PATCH 5/5] rust: device: Add a stub abstraction for devices Asahi Lina
2023-02-24 11:19 ` Greg Kroah-Hartman
2023-02-24 15:10 ` Asahi Lina
2023-02-24 15:34 ` Greg Kroah-Hartman
2023-02-24 15:51 ` Asahi Lina
2023-02-24 16:31 ` Greg Kroah-Hartman
2023-02-24 16:53 ` Asahi Lina
2023-03-05 6:39 ` Wedson Almeida Filho
2023-03-09 11:24 ` Greg Kroah-Hartman
2023-03-09 16:46 ` Wedson Almeida Filho
2023-03-09 17:11 ` Greg Kroah-Hartman
2023-03-09 19:06 ` Wedson Almeida Filho
2023-03-13 17:01 ` Gary Guo
2023-03-09 19:43 ` Miguel Ojeda
2023-03-13 17:52 ` Gary Guo
2023-03-13 18:05 ` Boqun Feng [this message]
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