linux-kernel - Re: About commit "io: change inX() to have their own IO barrier overrides"

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Message-ID: <90af535f-00ef-c1e3-ec20-aae2bd2a0d88@kernel.org>
Date:   Thu, 5 Mar 2020 22:44:08 -0500
From:   Sinan Kaya <okaya@...nel.org>
To:     Arnd Bergmann <arnd@...db.de>, John Garry <john.garry@...wei.com>
Cc:     "xuwei (O)" <xuwei5@...ilicon.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Jiaxun Yang <jiaxun.yang@...goat.com>,
        linux-arch <linux-arch@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Will Deacon <will@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>
Subject: Re: About commit "io: change inX() to have their own IO barrier
 overrides"

On 3/3/2020 11:40 AM, Arnd Bergmann wrote:
>> -          ret = read##bw(PCI_IOBASE + addr);
>> +          __io_pbr();
>> +          ret = __raw_read##bw(PCI_IOBASE + addr);
>> +          __io_pbr();
> __io_par();
> 

Why do we need to change read##bw above?

read##bw already provides strong ordering guarantees across multiple
architectures.