Re: [RFC PATCH v1 5/9] uaccess: Switch to copy_{to/from}_user_partial() when relevant

Alice Ryhl <[email protected]> Mon, 27 Apr 2026 18:07:28 +0000
Newsgroups gmane.comp.freedesktop.xorg.drivers.intel,gmane.linux.ports.alpha,gmane.linux.kernel,gmane.linux.kernel.arc,gmane.linux.ports.arm.kernel,gmane.linux.ports.mips,gmane.linux.ports.ppc64.devel,gmane.comp.emulators.kvm.devel,gmane.linux.ports.riscv,gmane.linux.ports.sparc,gmane.linux.uml.devel,gmane.linux.kernel.efi,gmane.comp.freedesktop.amd-gfx,gmane.comp.video.dri.devel,gmane.linux.network,gmane.linux.kernel.wireless.general,gmane.linux.kernel.spi.devel,gmane.linux.drivers.video-input-infrastructure,gmane.linux.serial,gmane.linux.usb.general,gmane.comp.emulators.xen.devel,gmane.linux.file-systems,gmane.linux.kernel.bpf,gmane.linux.kernel.mm,gmane.linux.x25,gmane.linux.kernel.rust,gmane.linux.sound,gmane.linux.ports.hexagon,gmane.linux.ports.parisc,gmane.linux.ports.sh.devel,gmane.linux.kernel.cross-arch
Message-ID <[email protected]>
On Mon, Apr 27, 2026 at 07:13:46PM +0200, Christophe Leroy (CS GROUP) wrote:
> diff --git a/rust/helpers/uaccess.c b/rust/helpers/uaccess.c
> index 01de4fbbcc84..710e07cd60ae 100644
> --- a/rust/helpers/uaccess.c
> +++ b/rust/helpers/uaccess.c
> @@ -5,13 +5,13 @@
>  __rust_helper unsigned long
>  rust_helper_copy_from_user(void *to, const void __user *from, unsigned long n)
>  {
> -	return copy_from_user(to, from, n);
> +	return copy_from_user_partial(to, from, n);
>  }
>  
>  __rust_helper unsigned long
>  rust_helper_copy_to_user(void __user *to, const void *from, unsigned long n)
>  {
> -	return copy_to_user(to, from, n);
> +	return copy_to_user_partial(to, from, n);
>  }

No Rust code uses the return value for anything other than comparing it
with zero, so you can keep these as copy_[from|to]_user() without
issues.

Thanks, Alice