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From:   Michael Ellerman <mpe@ellerman.id.au>
To:     Linus Torvalds <torvalds@linux-foundation.org>,
        Will Deacon <will.deacon@arm.com>
Cc:     linux-arch <linux-arch@vger.kernel.org>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        "Paul E. McKenney" <paulmck@linux.ibm.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Andrea Parri <andrea.parri@amarulasolutions.com>,
        Palmer Dabbelt <palmer@sifive.com>,
        Daniel Lustig <dlustig@nvidia.com>,
        David Howells <dhowells@redhat.com>,
        Alan Stern <stern@rowland.harvard.edu>,
        "Maciej W. Rozycki" <macro@linux-mips.org>,
        Paul Burton <paul.burton@mips.com>,
        Ingo Molnar <mingo@kernel.org>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Rich Felker <dalias@libc.org>, Tony Luck <tony.luck@intel.com>
Subject: Re: [PATCH 00/20] Remove Mysterious Macro Intended to Obscure Weird Behaviours (mmiowb())
In-Reply-To: <CAHk-=wio4duTk=dPJZ+yW-Y-65Q4O8Hc09bexAqs4OQV1R3WhQ@mail.gmail.com>
References: <20190301140348.25175-1-will.deacon@arm.com> <CAHk-=wio4duTk=dPJZ+yW-Y-65Q4O8Hc09bexAqs4OQV1R3WhQ@mail.gmail.com>
Date:   Sat, 02 Mar 2019 23:56:44 +1100
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Linus Torvalds <torvalds@linux-foundation.org> writes:

> Love the acronym, and the series looks good to me.
>
> Michael - can you check (or maybe you already did?) that this works
> for ppc too, and doesn't have any gotcha's?

Yeah it looks fine to me.

I gave it a quick boot with a patch to count how many mb()s we actually
issue in the spin_unlock() path and it's definitely hitting that path
correctly. So it works at least as well as the old code.

cheers