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From:   Michael Kelley <mikelley@microsoft.com>
To:     Wei Hu <weh@microsoft.com>, KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        "wei.liu@kernel.org" <wei.liu@kernel.org>,
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        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Dexuan Cui <decui@microsoft.com>
Subject: RE: [PATCH v3] PCI: hv: Fix a timing issue which causes kdump to fail
 occasionally
Thread-Topic: [PATCH v3] PCI: hv: Fix a timing issue which causes kdump to
 fail occasionally
Thread-Index: AQHWXLZO4rg806/YAkqpm5I8FMMzTqkQq3Jg
Date:   Mon, 20 Jul 2020 16:27:59 +0000
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References: <20200718034752.4843-1-weh@microsoft.com>
In-Reply-To: <20200718034752.4843-1-weh@microsoft.com>
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From: Wei Hu <weh@microsoft.com> Sent: Friday, July 17, 2020 8:48 PM
> To: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang <haiyangz@microsoft.=
com>;
> Stephen Hemminger <sthemmin@microsoft.com>; wei.liu@kernel.org;
> lorenzo.pieralisi@arm.com; robh@kernel.org; bhelgaas@google.com; linux-
> hyperv@vger.kernel.org; linux-pci@vger.kernel.org; linux-kernel@vger.kern=
el.org; Dexuan
> Cui <decui@microsoft.com>; Michael Kelley <mikelley@microsoft.com>
> Cc: Wei Hu <weh@microsoft.com>
> Subject: [PATCH v3] PCI: hv: Fix a timing issue which causes kdump to fai=
l occasionally
>=20
> Kdump could fail sometime on Hyper-V guest over Accelerated Network
> interface. This is because the retry in hv_pci_enter_d0() relies on
> an asynchronous host event arriving before the guest calls
> hv_send_resources_allocated(). Fix the problem by moving retry
> to hv_pci_probe(), removing this dependency and making the calling
> sequence synchronous.
>=20
> Fixes: c81992e7f4aa ("PCI: hv: Retry PCI bus D0 entry on invalid device s=
tate")
> Signed-off-by: Wei Hu <weh@microsoft.com>
> ---
>     v2: Adding Fixes tag according to Michael Kelley's review comment.
>     v3: Fix couple typos and reword commit message to make it clearer.
>     Thanks the comments from Bjorn Helgaas.
>=20
>  drivers/pci/controller/pci-hyperv.c | 66 ++++++++++++++---------------
>  1 file changed, 32 insertions(+), 34 deletions(-)
>=20

I gave my Reviewed-by on the earlier v1 of this patch, but reiterating it
here:

Reviewed-by: Michael Kelley <mikelley@microsoft.com>