[asahilinux:bits/250-aop 34/69] warning: length comparison to zero

[kernel test robot <lkp@intel.com>]

Hi Asahi,

FYI, the error/warning still remains.

tree:   https://github.com/AsahiLinux/linux bits/250-aop
head:   234b16b06a9869c5885af57b2853412e854c1216
commit: 92fe4dbd22e7faafad04ddf06d732e336ea7be98 [34/69] Rust: io: Add memcpy_fromio wrapper
config: x86_64-rhel-9.4-rust (https://download.01.org/0day-ci/archive/20260417/202604170958.8AwfIZnj-lkp@intel.com/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/20260417/202604170958.8AwfIZnj-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202604170958.8AwfIZnj-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> warning: length comparison to zero
   --> rust/kernel/io.rs:283:12
   |
   283 |         if buffer.len() == 0 || !Self::length_valid(offset, buffer.len(), self.maxsize()) {
   |            ^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `buffer.is_empty()`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#len_zero
   = note: `-W clippy::len-zero` implied by `-W clippy::all`
   = help: to override `-W clippy::all` add `#[allow(clippy::len_zero)]`

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki