linux-kernel - Re: Simplify load_unaligned_zeropad() (was Re: [GIT PULL] Ceph updates for 5.20-rc1)

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Message-ID: <Yvqn8BqE7FdB6Ccd@worktop.programming.kicks-ass.net>
Date:   Mon, 15 Aug 2022 22:09:20 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Al Viro <viro@...iv.linux.org.uk>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Jeff Layton <jlayton@...nel.org>,
        Ilya Dryomov <idryomov@...il.com>, ceph-devel@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Matthew Wilcox <willy@...radead.org>,
        clang-built-linux <llvm@...ts.linux.dev>
Subject: Re: Simplify load_unaligned_zeropad() (was Re: [GIT PULL] Ceph
 updates for 5.20-rc1)

On Mon, Aug 15, 2022 at 08:58:21AM -0700, Linus Torvalds wrote:
> And no, disassembling the instruction wouldn't kill us either (we know
> it's a "mov" instruction, so it's just the modrm bytes), but again it
> really didn't seem worth the pain. The generated code with the fixed
> registers wasn't optimal, but it was close enough that it really
> doesn't seem to matter.

I'm not at all suggesting we do this; but it might be
insn_get_addr_ref() does what is needed.