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From:   "Zhao, Haifeng" <haifeng.zhao@intel.com>
To:     Joe Perches <joe@perches.com>,
        "bhelgaas@google.com" <bhelgaas@google.com>,
        "oohall@gmail.com" <oohall@gmail.com>,
        "ruscur@russell.cc" <ruscur@russell.cc>,
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CC:     "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Jia, Pei P" <pei.p.jia@intel.com>,
        "ashok.raj@linux.intel.com" <ashok.raj@linux.intel.com>,
        "Kuppuswamy, Sathyanarayanan" <sathyanarayanan.kuppuswamy@intel.com>,
        "hch@infradead.org" <hch@infradead.org>
Subject: RE: [PATCH 4/5 V4] PCI: only return true when dev io state is really
 changed
Thread-Topic: [PATCH 4/5 V4] PCI: only return true when dev io state is really
 changed
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Date:   Mon, 28 Sep 2020 01:47:28 +0000
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         <20200927082736.14633-5-haifeng.zhao@intel.com>
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Sorry for that offence, I should ask for your permission.=20

-----Original Message-----
From: Joe Perches <joe@perches.com>=20
Sent: Sunday, September 27, 2020 5:14 PM
To: Zhao, Haifeng <haifeng.zhao@intel.com>; bhelgaas@google.com; oohall@gma=
il.com; ruscur@russell.cc; lukas@wunner.de; andriy.shevchenko@linux.intel.c=
om; stuart.w.hayes@gmail.com; mr.nuke.me@gmail.com; mika.westerberg@linux.i=
ntel.com
Cc: linux-pci@vger.kernel.org; linux-kernel@vger.kernel.org; Jia, Pei P <pe=
i.p.jia@intel.com>; ashok.raj@linux.intel.com; Kuppuswamy, Sathyanarayanan =
<sathyanarayanan.kuppuswamy@intel.com>; hch@infradead.org
Subject: Re: [PATCH 4/5 V4] PCI: only return true when dev io state is real=
ly changed

On Sun, 2020-09-27 at 04:27 -0400, Ethan Zhao wrote:
> When uncorrectable error happens, AER driver and DPC driver interrupt=20
> handlers likely call
>=20
>    pcie_do_recovery()
>    ->pci_walk_bus()
>      ->report_frozen_detected()
>=20
> with pci_channel_io_frozen the same time.
>    If pci_dev_set_io_state() return true even if the original state is=20
> pci_channel_io_frozen, that will cause AER or DPC handler re-enter the=20
> error detecting and recovery procedure one after another.
>    The result is the recovery flow mixed between AER and DPC.
> So simplify the pci_dev_set_io_state() function to only return true=20
> when dev->error_state is changed.
>=20
> Signed-off-by: Ethan Zhao <haifeng.zhao@intel.com>
> Tested-by: Wen Jin <wen.jin@intel.com>
> Tested-by: Shanshan Zhang <ShanshanX.Zhang@intel.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
> Reviewed-by: Joe Perches <joe@perches.com>

Hi Ethan/Haifeng.

Like Andy, I did not "review" this patch and sign it.
I merely suggested another simplification.
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