Re: [PATCH] rust: seq_file: add puts, putc, write, and hex_dump methods

[kernel test robot]

Hi Christian,

kernel test robot noticed the following build errors:

[auto build test ERROR on brauner-vfs/vfs.all]
[also build test ERROR on rust/rust-next linus/master v7.0-rc7 next-20260407]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Christian-Benton/rust-seq_file-add-puts-putc-write-and-hex_dump-methods/20260407-211720
base:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git vfs.all
patch link:    https://lore.kernel.org/r/20260403233900.24640-1-t1bur0n.kernel.org%40protonmail.ch
patch subject: [PATCH] rust: seq_file: add puts, putc, write, and hex_dump methods
config: x86_64-rhel-9.4-rust (https://download.01.org/0day-ci/archive/20260408/202604080005.U3yjfXzs-lkp@xxxxxxxxx/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
rustc: rustc 1.88.0 (6b00bc388 2025-06-23)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260408/202604080005.U3yjfXzs-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202604080005.U3yjfXzs-lkp@xxxxxxxxx/

All error/warnings (new ones prefixed by >>):

   PATH=/opt/cross/clang-20/bin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
   INFO PATH=/opt/cross/rustc-1.88.0-bindgen-0.72.1/cargo/bin:/opt/cross/clang-20/bin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
   /usr/bin/timeout -k 100 12h /usr/bin/make KCFLAGS=\ -fno-crash-diagnostics\ -Wno-error=return-type\ -Wreturn-type\ -funsigned-char\ -Wundef\ -falign-functions=64 W=1 --keep-going LLVM=1 -j32 -C source O=/kbuild/obj/consumer/x86_64-rhel-9.4-rust ARCH=x86_64 SHELL=/bin/bash rustfmtcheck 
   make: Entering directory '/kbuild/src/consumer'
   make[1]: Entering directory '/kbuild/obj/consumer/x86_64-rhel-9.4-rust'
>> Diff in rust/kernel/seq_file.rs:4:
    //!
    //! C header: [`include/linux/seq_file.h`](srctree/include/linux/seq_file.h)
    
   -use crate::{bindings, ffi, fmt, str::CStr, str::CStrExt as _, types::NotThreadSafe, types::Opaque};
   +use crate::{
   +    bindings, ffi, fmt, str::CStr, str::CStrExt as _, types::NotThreadSafe, types::Opaque,
   +};
    
    /// A utility for generating the contents of a seq file.
    #[repr(transparent)]
>> Diff in rust/kernel/seq_file.rs:4:
    //!
    //! C header: [`include/linux/seq_file.h`](srctree/include/linux/seq_file.h)
    
   -use crate::{bindings, ffi, fmt, str::CStr, str::CStrExt as _, types::NotThreadSafe, types::Opaque};
   +use crate::{
   +    bindings, ffi, fmt, str::CStr, str::CStrExt as _, types::NotThreadSafe, types::Opaque,
   +};
    
    /// A utility for generating the contents of a seq file.
    #[repr(transparent)]
   make[2]: *** [Makefile:1916: rustfmt] Error 123
   make[1]: Leaving directory '/kbuild/obj/consumer/x86_64-rhel-9.4-rust'
   make[1]: *** [Makefile:248: __sub-make] Error 2
   make[2]: Target 'rustfmtcheck' not remade because of errors.
   make[1]: Target 'rustfmtcheck' not remade because of errors.
   make: *** [Makefile:248: __sub-make] Error 2
   make: Target 'rustfmtcheck' not remade because of errors.
   make: Leaving directory '/kbuild/src/consumer'
--
>> warning: methods called `as_*` usually take `self` by reference or `self` by mutable reference
   --> rust/kernel/seq_file.rs:27:17
   |
   27 |     fn as_c_int(self) -> ffi::c_int {
   |                 ^^^^
   |
   = help: consider choosing a less ambiguous name
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#wrong_self_convention
   = note: `-W clippy::wrong-self-convention` implied by `-W clippy::all`
   = help: to override `-W clippy::all` add `#[allow(clippy::wrong_self_convention)]`
--
>> warning: casts from `u8` to `i32` can be expressed infallibly using `From`
   --> rust/kernel/seq_file.rs:119:17
   |
   119 |                 rowsize as ffi::c_int,
   |                 ^^^^^^^^^^^^^^^^^^^^^
   |
   = help: an `as` cast can become silently lossy if the types change in the future
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cast_lossless
   = note: requested on the command line with `-W clippy::cast-lossless`
   help: use `ffi::c_int::from` instead
   |
   119 -                 rowsize as ffi::c_int,
   119 +                 ffi::c_int::from(rowsize),
   |
--
>> warning: casts from `u8` to `i32` can be expressed infallibly using `From`
   --> rust/kernel/seq_file.rs:120:17
   |
   120 |                 groupsize as ffi::c_int,
   |                 ^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: an `as` cast can become silently lossy if the types change in the future
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cast_lossless
   help: use `ffi::c_int::from` instead
   |
   120 -                 groupsize as ffi::c_int,
   120 +                 ffi::c_int::from(groupsize),
   |

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