From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Dexuan Cui <decui@microsoft.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
Stephen Hemminger <sthemmin@microsoft.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"driverdev-devel@linuxdriverproject.org"
<driverdev-devel@linuxdriverproject.org>,
KY Srinivasan <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Sasha Levin <Alexander.Levin@microsoft.com>,
Michael Kelley <mikelley@microsoft.com>
Subject: Re: [PATCH] PCI: hv: Add hv_pci_remove_slots() when we unload the driver
Date: Tue, 12 Feb 2019 12:12:42 +0000 [thread overview]
Message-ID: <20190212121235.GA23166@e107981-ln.cambridge.arm.com> (raw)
In-Reply-To: <PU1P153MB0169F06340FC519C2802C5CFBF680@PU1P153MB0169.APCP153.PROD.OUTLOOK.COM>
On Thu, Feb 07, 2019 at 08:36:32PM +0000, Dexuan Cui wrote:
>
> When we unload pci-hyperv, the host doesn't send us a PCI_EJECT message.
> In this case we also need to make sure the sysfs pci slot directory
> is removed, otherwise "cat /sys/bus/pci/slots/2/address" will trigger
> "BUG: unable to handle kernel paging request". And, if we unload/reload
> the driver several times, we'll have multiple pci slot directories in
> /sys/bus/pci/slots/ like this:
>
> root@localhost:~# ls -rtl /sys/bus/pci/slots/
> total 0
> drwxr-xr-x 2 root root 0 Feb 7 10:49 2
> drwxr-xr-x 2 root root 0 Feb 7 10:49 2-1
> drwxr-xr-x 2 root root 0 Feb 7 10:51 2-2
>
> The patch adds the missing code, and in hv_eject_device_work() it also
> moves pci_destroy_slot() to an earlier place where we hold the pci lock.
This patch fixes three bugs:
1) set hpdev->pci_slot to NULL
2) move code destroying the slot inside a locked region in
hv_eject_device_work()
3) Add missing slots removal code in hv_pci_remove()
We need three patches, not one.
(1) and (2), I am not entirely sure we want them in stable kernels,
since they are potential bugs, waiting for your input.
Lorenzo
> Fixes: a15f2c08c708 ("PCI: hv: support reporting serial number as slot information")
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> Cc: stable@vger.kernel.org
> Cc: Stephen Hemminger <sthemmin@microsoft.com>
> ---
> drivers/pci/controller/pci-hyperv.c | 23 ++++++++++++++++++++---
> 1 file changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index 9ba4d12c179c..6b4773727525 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -1491,6 +1491,21 @@ static void hv_pci_assign_slots(struct hv_pcibus_device *hbus)
> }
> }
>
> +/*
> + * Remove entries in sysfs pci slot directory.
> + */
> +static void hv_pci_remove_slots(struct hv_pcibus_device *hbus)
> +{
> + struct hv_pci_dev *hpdev;
> +
> + list_for_each_entry(hpdev, &hbus->children, list_entry) {
> + if (!hpdev->pci_slot)
> + continue;
> + pci_destroy_slot(hpdev->pci_slot);
> + hpdev->pci_slot = NULL;
> + }
> +}
> +
> /**
> * create_root_hv_pci_bus() - Expose a new root PCI bus
> * @hbus: Root PCI bus, as understood by this driver
> @@ -1887,6 +1902,10 @@ static void hv_eject_device_work(struct work_struct *work)
> pci_lock_rescan_remove();
> pci_stop_and_remove_bus_device(pdev);
> pci_dev_put(pdev);
> + if (hpdev->pci_slot) {
> + pci_destroy_slot(hpdev->pci_slot);
> + hpdev->pci_slot = NULL;
> + }
> pci_unlock_rescan_remove();
> }
>
> @@ -1894,9 +1913,6 @@ static void hv_eject_device_work(struct work_struct *work)
> list_del(&hpdev->list_entry);
> spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags);
>
> - if (hpdev->pci_slot)
> - pci_destroy_slot(hpdev->pci_slot);
> -
> memset(&ctxt, 0, sizeof(ctxt));
> ejct_pkt = (struct pci_eject_response *)&ctxt.pkt.message;
> ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE;
> @@ -2682,6 +2698,7 @@ static int hv_pci_remove(struct hv_device *hdev)
> pci_lock_rescan_remove();
> pci_stop_root_bus(hbus->pci_bus);
> pci_remove_root_bus(hbus->pci_bus);
> + hv_pci_remove_slots(hbus);
> pci_unlock_rescan_remove();
> hbus->state = hv_pcibus_removed;
> }
> --
> 2.19.1
>
next prev parent reply other threads:[~2019-02-12 12:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-07 20:36 [PATCH] PCI: hv: Add hv_pci_remove_slots() when we unload the driver Dexuan Cui
2019-02-08 0:44 ` Stephen Hemminger
2019-02-12 12:12 ` Lorenzo Pieralisi [this message]
2019-02-13 0:17 ` Dexuan Cui
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