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Subject: RE: [PATCH v2 4/6] Revert "PCI: hv: Fix a timing issue which causes
 kdump to fail occasionally"
Thread-Topic: [PATCH v2 4/6] Revert "PCI: hv: Fix a timing issue which causes
 kdump to fail occasionally"
Thread-Index: AQHZZpopUQZ8ge3HAEe7nozotRXSl68gDtTw
Date:   Fri, 7 Apr 2023 16:33:21 +0000
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References: <20230404020545.32359-1-decui@microsoft.com>
 <20230404020545.32359-5-decui@microsoft.com>
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From: Dexuan Cui <decui@microsoft.com> Sent: Monday, April 3, 2023 7:06 PM
>=20
> This reverts commit d6af2ed29c7c1c311b96dac989dcb991e90ee195.
>=20
> The statement "the hv_pci_bus_exit() call releases structures of all its
> child devices" in commit d6af2ed29c7c is not true: in the path
> hv_pci_probe() -> hv_pci_enter_d0() -> hv_pci_bus_exit(hdev, true): the
> parameter "keep_devs" is true, so hv_pci_bus_exit() does *not* release th=
e
> child "struct hv_pci_dev *hpdev" that is created earlier in
> pci_devices_present_work() -> new_pcichild_device().
>=20
> The commit d6af2ed29c7c was originally made in July 2020 for RHEL 7.7,
> where the old version of hv_pci_bus_exit() was used; when the commit was
> rebased and merged into the upstream, people didn't notice that it's
> not really necessary. The commit itself doesn't cause any issue, but it
> makes hv_pci_probe() more complicated. Revert it to facilitate some
> upcoming changes to hv_pci_probe().
>=20
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> Acked-by: Wei Hu <weh@microsoft.com>
> Cc: stable@vger.kernel.org
> ---
>=20
> v2:
>   No change to the patch body.
>   Added Wei Hu's Acked-by.
>   Added Cc:stable
>=20
>  drivers/pci/controller/pci-hyperv.c | 71 ++++++++++++++---------------
>  1 file changed, 34 insertions(+), 37 deletions(-)
>=20

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