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Date:   Mon, 29 May 2023 13:29:37 +0200
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Subject: Re: [RFC][PATCH 0/2] Lock and Pointer guards
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To:     Peter Zijlstra <peterz@infradead.org>,
        torvalds@linux-foundation.org, keescook@chromium.org,
        gregkh@linuxfoundation.org
Cc:     linux-kernel@vger.kernel.org, ojeda@kernel.org,
        ndesaulniers@google.com, mingo@redhat.com, will@kernel.org,
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        bristot@redhat.com, vschneid@redhat.com, paulmck@kernel.org,
        frederic@kernel.org, quic_neeraju@quicinc.com,
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        qiang1.zhang@intel.com, rcu@vger.kernel.org, tj@kernel.org,
        tglx@linutronix.de
References: <20230526150549.250372621@infradead.org>
From:   Paolo Bonzini <pbonzini@redhat.com>
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On 5/26/23 17:05, Peter Zijlstra wrote:
> My initial (failed) attempts tried to combine __cleanup, _Generic and
> __auto_type, but the compilers refused. I've also Googled around and found
> (among many others) the QEMU and Glib guards. However I don't like them because
> they end up relying on function pointers/indirect calls.
> 
> Hence the current pile of CPP hackery.. no indirect calls in sight.

QEMU's guards in practice also compiles down to direct calls, but yes 
that's only after the compiler inlines everything in the vtable.  I did 
it that way because the polymorphic locks already existed before, 
otherwise your solution with Linus's tweak for "bool" is as nice as it 
can be.  I like that it extends to irqoff and irqsave sections.

Paolo