On Thu, Jul 3, 2025 at 6:41 PM Tamir Duberstein tamird@gmail.com wrote:
On Thu, Jul 3, 2025 at 4:36 PM Benno Lossin lossin@kernel.org wrote:
On Thu Jul 3, 2025 at 8:55 PM CEST, Tamir Duberstein wrote:
On Thu, Jul 3, 2025 at 11:08 AM Benno Lossin lossin@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@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@google.com > Link: https://rust-for-linux.zulipchat.com/#narrow/channel/288089-General/topic/Cu... > Acked-by: Greg Kroah-Hartman gregkh@linuxfoundation.org > Reviewed-by: Alice Ryhl aliceryhl@google.com > Signed-off-by: Tamir Duberstein tamird@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.
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 don't understand, can't you just do:
- add `rust/kernel/fmt.rs`,
- add `rust/macros/fmt.rs`,
- change all occurrences of `core::fmt` to `kernel::fmt` and `format_args!` to `fmt!`.
Yes, such a split could be done - I will do so in the next spin
The last one could be split by subsystem, no? Some subsystems might interact and thus need simultaneous splitting, but there should be some independent ones.
Yes, it probably can. As you say, some subsystems might interact - the claimed benefit of doing this subsystem-by-subsystem split is that it avoids conflicts with ongoing work that will conflict with a large patch, but this is also the downside; if ongoing work changes the set of interactions between subsystems then a maintainer may find themselves unable to emit the log message they want (because one subsystem is using kernel::fmt while another is still on core::fmt).
I gave this a try. I ran into the problem that `format_args!` (and, after this patch, `fmt!`) is at the center of `print_macro!`, which itself underpins various other formatting macros. This means we'd have to bifurcate the formatting infrastructure to support an incremental migration. That's quite a bit of code, and likely quite a mess in the resulting git history -- and that's setting aside the toil required to figure out the correct combinations of subsystems that must migrate together.