It is slightly more convenient to operate on mut pointers, and this also
properly conveys the desired ownership semantics of the trait.
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241120-borrow-mut-v6-4-80dbadd00951@gmail.com
[ Reworded title slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
The sibling `build_assert!` is already in the prelude, it makes sense
that a "core"/"language" facility like this is part of the prelude and
users should not be defining their own one (thus there should be no risk
of future name collisions and we would want to be aware of them anyway).
Thus add `build_error!` into the prelude.
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20241123222849.350287-3-ojeda@kernel.org
[ Applied the change to the new miscdevice cases. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Code and some examples were using the function, rather than the macro. The
macro is what is documented.
Thus move users to the macro.
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20241123222849.350287-1-ojeda@kernel.org
[ Applied the change to the new miscdevice cases. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
The following FFI types are replaced compared to `core::ffi`:
1. `char` type is now always mapped to `u8`, since kernel uses
`-funsigned-char` on the C code. `core::ffi` maps it to platform
default ABI, which can be either signed or unsigned.
2. `long` is now always mapped to `isize`. It's very common in the
kernel to use `long` to represent a pointer-sized integer, and in
fact `intptr_t` is a typedef of `long` in the kernel. Enforce this
mapping rather than mapping to `i32/i64` depending on platform can
save us a lot of unnecessary casts.
Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240913213041.395655-5-gary@garyguo.net
[ Moved `uaccess` changes from the next commit, since they were
irrefutable patterns that Rust >= 1.82.0 warns about. Reworded
slightly and reformatted a few documentation comments. Rebased on
top of `rust-next`. Added the removal of two casts to avoid Clippy
warnings. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
In the last kernel cycle we migrated most of the `core::ffi` cases in
commit d072acda48 ("rust: use custom FFI integer types"):
Currently FFI integer types are defined in libcore. This commit
creates the `ffi` crate and asks bindgen to use that crate for FFI
integer types instead of `core::ffi`.
This commit is preparatory and no type changes are made in this
commit yet.
Finish now the few remaining/new cases so that we perform the actual
remapping in the next commit as planned.
Acked-by: Jocelyn Falempe <jfalempe@redhat.com> # drm
Link: https://lore.kernel.org/rust-for-linux/CANiq72m_rg42SvZK=bF2f0yEoBLVA33UBhiAsv8THhVu=G2dPA@mail.gmail.com/
Link: https://lore.kernel.org/all/cc9253fa-9d5f-460b-9841-94948fb6580c@redhat.com/
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
When building miscdevice with clippy warnings, the following warning is
emitted:
warning: casting to the same type is unnecessary (`u32` -> `u32`)
--> /home/aliceryhl/rust-for-linux/rust/kernel/miscdevice.rs:220:28
|
220 | match T::ioctl(device, cmd as u32, arg as usize) {
| ^^^^^^^^^^ help: try: `cmd`
|
= help: for further information visit
https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast
= note: `-W clippy::unnecessary-cast` implied by `-W clippy::all`
= help: to override `-W clippy::all` add `#[allow(clippy::unnecessary_cast)]`
Thus, fix it.
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20241015-miscdevice-cint-cast-v1-1-fcf4b75700ac@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Provide a `MiscDevice` trait that lets you specify the file operations
that you wish to provide for your misc device. For now, only three file
operations are provided: open, close, ioctl.
These abstractions only support MISC_DYNAMIC_MINOR. This enforces that
new miscdevices should not hard-code a minor number.
When implementing ioctl, the Result type is used. This means that you
can choose to return either of:
* An integer of type isize.
* An errno using the kernel::error::Error type.
When returning an isize, the integer is returned verbatim. It's mainly
intended for returning positive integers to userspace. However, it is
technically possible to return errors via the isize return value too.
To avoid having a dependency on files, this patch does not provide the
file operations callbacks a pointer to the file. This means that they
cannot check file properties such as O_NONBLOCK (which Binder needs).
Support for that can be added as a follow-up.
To avoid having a dependency on vma, this patch does not provide any way
to implement mmap (which Binder needs). Support for that can be added as
a follow-up.
Rust Binder will use these abstractions to create the /dev/binder file
when binderfs is disabled.
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/rust-for-linux/20240328195457.225001-1-wedsonaf@gmail.com/
Link: https://lore.kernel.org/r/20241001-b4-miscdevice-v2-2-330d760041fa@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
