netdev - Re: [PATCH 14/18] maccess: allow architectures to provide kernel probing directly

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Date:   Wed, 13 May 2020 21:40:03 +0200
From:   Christoph Hellwig <hch@....de>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Christoph Hellwig <hch@....de>,
        the arch/x86 maintainers <x86@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-parisc@...r.kernel.org,
        linux-um <linux-um@...ts.infradead.org>,
        Netdev <netdev@...r.kernel.org>, bpf@...r.kernel.org,
        Linux-MM <linux-mm@...ck.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 14/18] maccess: allow architectures to provide kernel
 probing directly

On Wed, May 13, 2020 at 12:36:18PM -0700, Linus Torvalds wrote:
> > +               arch_kernel_read(dst, src, type, err_label);            \
> 
> I'm wondering if
> 
>  (a) we shouldn't expose this as an interface in general

We do export something like it, currently it is called
probe_kernel_address, and the last patch renames it to
get_kernel_nofault.  However it is implemented as a wrapper
around probe_kernel_address / copy_from_kernel_nofault and thus
not quite as efficient and without the magic goto semantics.

>  (b) it wouldn't be named differently..

It probably should with all the renaming..