From: Alice Ryhl <aliceryhl@google.com>
To: nmi@metaspace.dk
Cc: alex.gaynor@gmail.com, aliceryhl@google.com,
benno.lossin@proton.me, bjorn3_gh@protonmail.com,
boqun.feng@gmail.com, gary@garyguo.net, jiangshanlai@gmail.com,
linux-kernel@vger.kernel.org, ojeda@kernel.org,
patches@lists.linux.dev, rust-for-linux@vger.kernel.org,
tj@kernel.org, wedsonaf@gmail.com
Subject: Re: [PATCH v1 6/7] rust: workqueue: add safe API to workqueue
Date: Wed, 31 May 2023 14:07:49 +0000 [thread overview]
Message-ID: <20230531140749.3708572-1-aliceryhl@google.com> (raw)
In-Reply-To: <87bki29jsc.fsf@metaspace.dk>
Andreas Hindborg <nmi@metaspace.dk> writes:
> Alice Ryhl <aliceryhl@google.com> writes:
>> +unsafe impl<T> WorkItem for Arc<T>
>> +where
>> + T: ArcWorkItem + HasWork<Self> + ?Sized,
>> +{
>> + type EnqueueOutput = Result<(), Self>;
>> +
>> + unsafe fn __enqueue<F>(self, queue_work_on: F) -> Self::EnqueueOutput
>> + where
>> + F: FnOnce(*mut bindings::work_struct) -> bool,
>> + {
>> + let ptr = Arc::into_raw(self);
>> +
>> + // Using `get_work_offset` here for object-safety.
>> + //
>> + // SAFETY: The pointer is valid since we just got it from `into_raw`.
>> + let off = unsafe { (&*ptr).get_work_offset() };
>> +
>> + // SAFETY: The `HasWork` impl promises that this offset gives us a field of type
>> + // `Work<Self>` in the same allocation.
>> + let work_ptr = unsafe { (ptr as *const u8).add(off) as *const Work<Self> };
>
> We have this functionality in the default impl of
> `HasWork<T>::raw_get_work() where Self: Sized`. I am uncertain about the
> `Sized` bound. If it is sound to do the offset calculation here where
> `T: ?Sized`, it should also be sound in the default implementation of
> `HasWork<T>`. Should we not be able to change the bound on
> `HasWork<T>::raw_get_work()` to `Self: ?Sized` and call into that from
> here?
>
> let work_ptr = unsafe { <T as HasWork<Self>>::raw_get_work(ptr as _) };
>
> Same for Box.
>
> BR Andreas
I looked into this, and it seems like we can remove `Self: Sized` bound
from `raw_get_work`, so I am able to simplify this code somewhat.
However, it cannot be removed from `container_of`.
Thanks,
Alice
next prev parent reply other threads:[~2023-05-31 14:17 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-17 20:31 [PATCH v1 0/7] Bindings for the workqueue Alice Ryhl
2023-05-17 20:31 ` [PATCH v1 1/7] rust: workqueue: add low-level workqueue bindings Alice Ryhl
2023-05-18 14:51 ` Martin Rodriguez Reboredo
2023-05-19 9:40 ` Alice Ryhl
2023-05-19 12:04 ` Martin Rodriguez Reboredo
2023-05-23 10:03 ` Alice Ryhl
2023-05-30 8:26 ` Andreas Hindborg
2023-05-17 20:31 ` [PATCH v1 2/7] rust: add offset_of! macro Alice Ryhl
2023-05-18 14:51 ` Martin Rodriguez Reboredo
2023-05-23 15:48 ` Gary Guo
2023-05-24 12:26 ` Alice Ryhl
2023-05-30 8:40 ` Andreas Hindborg
2023-05-17 20:31 ` [PATCH v1 3/7] rust: sync: add `Arc::{from_raw, into_raw}` Alice Ryhl
2023-05-18 14:51 ` Martin Rodriguez Reboredo
2023-05-23 15:43 ` Gary Guo
2023-05-24 11:19 ` Alice Ryhl
2023-05-24 10:20 ` Andreas Hindborg
2023-05-24 11:11 ` Alice Ryhl
2023-05-25 7:45 ` Andreas Hindborg
2023-05-25 16:32 ` Gary Guo
2023-05-30 7:23 ` Andreas Hindborg
2023-05-17 20:31 ` [PATCH v1 4/7] rust: workqueue: define built-in queues Alice Ryhl
2023-05-18 14:52 ` Martin Rodriguez Reboredo
2023-05-25 11:40 ` Andreas Hindborg
2023-05-31 14:02 ` Alice Ryhl
2023-06-02 10:23 ` Andreas Hindborg (Samsung)
2023-05-17 20:31 ` [PATCH v1 5/7] rust: workqueue: add helper for defining work_struct fields Alice Ryhl
2023-05-18 23:18 ` Martin Rodriguez Reboredo
2023-05-24 14:50 ` Benno Lossin
2023-05-30 8:44 ` Andreas Hindborg
2023-05-31 9:00 ` Alice Ryhl
2023-05-31 10:18 ` Andreas Hindborg
2023-05-17 20:31 ` [PATCH v1 6/7] rust: workqueue: add safe API to workqueue Alice Ryhl
2023-05-19 0:17 ` Martin Rodriguez Reboredo
2023-05-23 11:07 ` Alice Ryhl
2023-05-30 7:19 ` Andreas Hindborg
2023-05-30 13:23 ` Martin Rodriguez Reboredo
2023-05-30 14:13 ` Miguel Ojeda
2023-05-24 14:51 ` Benno Lossin
2023-05-31 9:07 ` Alice Ryhl
2023-05-30 8:51 ` Andreas Hindborg
2023-05-31 14:07 ` Alice Ryhl [this message]
2023-05-17 20:31 ` [PATCH v1 7/7] rust: workqueue: add `try_spawn` helper method Alice Ryhl
2023-05-19 0:22 ` Martin Rodriguez Reboredo
2023-05-24 14:52 ` Benno Lossin
2023-05-31 14:03 ` Alice Ryhl
2023-05-17 21:48 ` [PATCH v1 0/7] Bindings for the workqueue Tejun Heo
2023-05-17 22:22 ` Alice Ryhl
2023-05-23 14:08 ` Andreas Hindborg
2023-05-23 14:14 ` Andreas Hindborg
2023-05-24 12:33 ` Alice Ryhl
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230531140749.3708572-1-aliceryhl@google.com \
--to=aliceryhl@google.com \
--cc=alex.gaynor@gmail.com \
--cc=benno.lossin@proton.me \
--cc=bjorn3_gh@protonmail.com \
--cc=boqun.feng@gmail.com \
--cc=gary@garyguo.net \
--cc=jiangshanlai@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=nmi@metaspace.dk \
--cc=ojeda@kernel.org \
--cc=patches@lists.linux.dev \
--cc=rust-for-linux@vger.kernel.org \
--cc=tj@kernel.org \
--cc=wedsonaf@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).