linux-kernel - RE: [PATCH 2/2] pci-hyperv: properly handle device eject

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Message-ID: <MWHPR03MB266914DE916753C042A8A7B0BFF10@MWHPR03MB2669.namprd03.prod.outlook.com>
Date:   Wed, 14 Sep 2016 05:45:07 +0000
From:   Dexuan Cui <decui@...rosoft.com>
To:     Long Li <longli@...rosoft.com>, KY Srinivasan <kys@...rosoft.com>,
        "Haiyang Zhang" <haiyangz@...rosoft.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>
CC:     "devel@...uxdriverproject.org" <devel@...uxdriverproject.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>
Subject: RE: [PATCH 2/2] pci-hyperv: properly handle device eject

> From: Long Li
> Sent: Wednesday, September 14, 2016 1:41
> 
> I think this code is safe here. If we reach the code
> pci_stop_and_remove_bus_device_locked, create_root_hv_pci_bus() is already
> called.

When hv_pci_probe() -> create_root_hv_pci_bus() -> pci_scan_child_bus() is running
on one cpu, I think nothing in the current code can prevent 
hv_eject_device_work() -> pci_stop_and_remove_bus_device_locked()
from running on another cpu?

The race window is pretty small however.

Thanks,
-- Dexuan