[PATCH v13 2/5] rust: support formatting of foreign types
Andrew Lunn
andrew at lunn.ch
Thu Jul 3 21:28:01 UTC 2025
On Thu, Jul 03, 2025 at 02:55:30PM -0400, Tamir Duberstein wrote:
> On Thu, Jul 3, 2025 at 11:08 AM Benno Lossin <lossin at kernel.org> wrote:
> >
> > On Thu Jul 3, 2025 at 3:55 PM CEST, Tamir Duberstein wrote:
> > > On Thu, Jul 3, 2025 at 5:32 AM Benno Lossin <lossin at kernel.org> wrote:
> > >> On Tue Jul 1, 2025 at 6:49 PM CEST, Tamir Duberstein wrote:
> > >> > Introduce a `fmt!` macro which wraps all arguments in
> > >> > `kernel::fmt::Adapter` and a `kernel::fmt::Display` trait. This enables
> > >> > formatting of foreign types (like `core::ffi::CStr`) that do not
> > >> > implement `core::fmt::Display` due to concerns around lossy conversions which
> > >> > do not apply in the kernel.
> > >> >
> > >> > Replace all direct calls to `format_args!` with `fmt!`.
> > >> >
> > >> > Replace all implementations of `core::fmt::Display` with implementations
> > >> > of `kernel::fmt::Display`.
> > >> >
> > >> > Suggested-by: Alice Ryhl <aliceryhl at google.com>
> > >> > Link: https://rust-for-linux.zulipchat.com/#narrow/channel/288089-General/topic/Custom.20formatting/with/516476467
> > >> > Acked-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> > >> > Reviewed-by: Alice Ryhl <aliceryhl at google.com>
> > >> > Signed-off-by: Tamir Duberstein <tamird at gmail.com>
> > >> > ---
> > >> > drivers/block/rnull.rs | 2 +-
> > >> > drivers/gpu/nova-core/gpu.rs | 4 +-
> > >> > rust/kernel/block/mq.rs | 2 +-
> > >> > rust/kernel/device.rs | 2 +-
> > >> > rust/kernel/fmt.rs | 89 +++++++++++++++++++++++++++++++++++++++
> > >> > rust/kernel/kunit.rs | 6 +--
> > >> > rust/kernel/lib.rs | 1 +
> > >> > rust/kernel/prelude.rs | 3 +-
> > >> > rust/kernel/print.rs | 4 +-
> > >> > rust/kernel/seq_file.rs | 2 +-
> > >> > rust/kernel/str.rs | 22 ++++------
> > >> > rust/macros/fmt.rs | 99 ++++++++++++++++++++++++++++++++++++++++++++
> > >> > rust/macros/lib.rs | 19 +++++++++
> > >> > rust/macros/quote.rs | 7 ++++
> > >> > scripts/rustdoc_test_gen.rs | 2 +-
> > >> > 15 files changed, 236 insertions(+), 28 deletions(-)
> > >>
> > >> This would be a lot easier to review if he proc-macro and the call
> > >> replacement were different patches.
> > >>
> > >> Also the `kernel/fmt.rs` file should be a different commit.
> > >
> > > Can you help me understand why? The changes you ask to be separated
> > > would all be in different files, so why would separate commits make it
> > > easier to review?
> >
> > It takes less time to go through the entire patch and give a RB. I can
> > take smaller time chunks and don't have to get back into the entire
> > context of the patch when I don't have 30-60min available.
>
> Ah, I see what you mean. Yeah, the requirement to RB the entire patch
> does mean there's a benefit to smaller patches.
I often tell kernel newbies:
Lots of small patches which are obviously correct.
A small patch tends to be more obviously correct than a big patch. The
commit message is more focused and helpful because it refers to a
small chunk of code. Because the commit message is more focused, it
can answer questions reviewers might ask, before they ask them. If i
can spend 60 seconds looking at a patch and decide it looks correct,
i'm more likely to actually look at it and give a reviewed by. If i
need to find 10 minutes, it is going to get put off for a later
time. Many reviewers just have a few minutes here, a few there,
slotted into time between other tasks, while drinking coffee, etc.
Andrew
More information about the dri-devel
mailing list