On Thu, Jul 3, 2025 at 2:55 PM Tamir Duberstein <tamird@xxxxxxxxx> wrote: > > On Thu, Jul 3, 2025 at 11:08 AM Benno Lossin <lossin@xxxxxxxxxx> 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@xxxxxxxxxx> 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@xxxxxxxxxx> > > >> > Link: https://rust-for-linux.zulipchat.com/#narrow/channel/288089-General/topic/Custom.20formatting/with/516476467 > > >> > Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > >> > Reviewed-by: Alice Ryhl <aliceryhl@xxxxxxxxxx> > > >> > Signed-off-by: Tamir Duberstein <tamird@xxxxxxxxx> > > >> > --- > > >> > 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. > > > In this patch the biggest problem is the rename & addition of new > > things, maybe just adding 200 lines in those files could be okay to go > > together, see below for more. > > After implementing your suggestion of re-exporting things from > `kernel::fmt` the diffstat is > > 26 files changed, 253 insertions(+), 51 deletions(-) > > so I guess I could do all the additions in one patch, but then > *everything* else has to go in a single patch together because the > formatting macros either want core::fmt::Display or > kernel::fmt::Display; they can't work in a halfway state. > > > > > > I prefer to keep things in one commit because the changes are highly > > > interdependent. The proc macro doesn't make sense without > > > kernel/fmt.rs and kernel/fmt.rs is useless without the proc macro. > > > > I think that `Adapter`, the custom `Display` and their impl blocks > > don't need to be in the same commit as the proc-macro. They are related, > > but maybe someone is not well-versed in proc-macros and thus doesn't > > want to review that part. > > Sure, I guess I will split them. But as noted above: changing the > formatting macros and all the types' trait implementations has to be a > "flag day" change. > > > > > >> > diff --git a/rust/kernel/fmt.rs b/rust/kernel/fmt.rs > > >> > new file mode 100644 > > >> > index 000000000000..348d16987de6 > > >> > --- /dev/null > > >> > +++ b/rust/kernel/fmt.rs > > >> > @@ -0,0 +1,89 @@ > > >> > +// SPDX-License-Identifier: GPL-2.0 > > >> > + > > >> > +//! Formatting utilities. > > >> > + > > >> > +use core::fmt; > > >> > > >> I think we should pub export all types that we are still using from > > >> `core::fmt`. For example `Result`, `Formatter`, `Debug` etc. > > >> > > >> That way I can still use the same pattern of importing `fmt` and then > > >> writing > > >> > > >> impl fmt::Display for MyType { > > >> fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {} > > >> } > > > > > > Great idea, done for the next spin. It would be nice to be able to > > > lint against references to `core::fmt` outside of kernel/fmt.rs. > > > > I think there was something in clippy that can do that globally and we > > could allow that in this file? > > I didn't find anything suitable. Do you have one in mind? I think we want https://github.com/rust-lang/rust-clippy/issues/14807.
