[PATCH 1/2 v3] pci-hyperv: properly handle pci bus remove

[PATCH 1/2 v3] pci-hyperv: properly handle pci bus remove

[Long Li]

From: Long Li <longli@microsoft.com>

hv_pci_devices_present is called in hv_pci_remove when we remove a PCI device from host (e.g. by disabling SRIOV on a device). In hv_pci_remove, the bus is already removed before the call, so we don't need to rescan the bus in the workqueue scheduled from hv_pci_devices_present. By introducing status hv_pcibus_removed, we can avoid this situation.

Signed-off-by: Long Li <longli@microsoft.com>
Tested-by: Cathy Avery <cavery@redhat.com>
Reported-by: Xiaofeng Wang <xiaofwan@redhat.com>
---
 drivers/pci/host/pci-hyperv.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index a8deeca..4a37598 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -348,6 +348,7 @@ enum hv_pcibus_state {
 	hv_pcibus_init = 0,
 	hv_pcibus_probed,
 	hv_pcibus_installed,
+	hv_pcibus_removed,
 	hv_pcibus_maximum
 };
 
@@ -1481,13 +1482,24 @@ static void pci_devices_present_work(struct work_struct *work)
 		put_pcichild(hpdev, hv_pcidev_ref_initial);
 	}
 
-	/* Tell the core to rescan bus because there may have been changes. */
-	if (hbus->state == hv_pcibus_installed) {
+	switch (hbus->state) {
+	case hv_pcibus_installed:
+		/*
+		 * Tell the core to rescan bus
+		 * because there may have been changes.
+		 */
 		pci_lock_rescan_remove();
 		pci_scan_child_bus(hbus->pci_bus);
 		pci_unlock_rescan_remove();
-	} else {
+		break;
+
+	case hv_pcibus_init:
+	case hv_pcibus_probed:
 		survey_child_resources(hbus);
+		break;
+
+	default:
+		break;
 	}
 
 	up(&hbus->enum_sem);
@@ -2163,6 +2175,7 @@ static int hv_pci_probe(struct hv_device *hdev,
 	hbus = kzalloc(sizeof(*hbus), GFP_KERNEL);
 	if (!hbus)
 		return -ENOMEM;
+	hbus->state = hv_pcibus_init;
 
 	/*
 	 * The PCI bus "domain" is what is called "segment" in ACPI and
@@ -2305,6 +2318,7 @@ static int hv_pci_remove(struct hv_device *hdev)
 		pci_stop_root_bus(hbus->pci_bus);
 		pci_remove_root_bus(hbus->pci_bus);
 		pci_unlock_rescan_remove();
+		hbus->state = hv_pcibus_removed;
 	}
 
 	ret = hv_send_resources_released(hdev);
-- 
1.8.5.6

RE: [PATCH 1/2 v3] pci-hyperv: properly handle pci bus remove

[KY Srinivasan]

> -----Original Message-----
> From: Long Li
> Sent: Monday, October 3, 2016 11:43 PM
> To: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
> <haiyangz@microsoft.com>; Bjorn Helgaas <bhelgaas@google.com>
> Cc: devel@linuxdriverproject.org; linux-pci@vger.kernel.org; linux-
> kernel@vger.kernel.org; Long Li <longli@microsoft.com>
> Subject: [PATCH 1/2 v3] pci-hyperv: properly handle pci bus remove
> 
> This sender failed our fraud detection checks and may not be who they
> appear to be. Learn about spoofing at http://aka.ms/LearnAboutSpoofing
> 
> From: Long Li <longli@microsoft.com>
> 
> hv_pci_devices_present is called in hv_pci_remove when we remove a PCI
> device from host (e.g. by disabling SRIOV on a device). In hv_pci_remove,
> the bus is already removed before the call, so we don't need to rescan the
> bus in the workqueue scheduled from hv_pci_devices_present. By
> introducing status hv_pcibus_removed, we can avoid this situation.
> 
> Signed-off-by: Long Li <longli@microsoft.com>
> Tested-by: Cathy Avery <cavery@redhat.com>
> Reported-by: Xiaofeng Wang <xiaofwan@redhat.com>

Acked-by: KY Srinivasan <kys@microsoft.com>


> ---
>  drivers/pci/host/pci-hyperv.c | 20 +++++++++++++++++---
>  1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
> index a8deeca..4a37598 100644
> --- a/drivers/pci/host/pci-hyperv.c
> +++ b/drivers/pci/host/pci-hyperv.c
> @@ -348,6 +348,7 @@ enum hv_pcibus_state {
>         hv_pcibus_init = 0,
>         hv_pcibus_probed,
>         hv_pcibus_installed,
> +       hv_pcibus_removed,
>         hv_pcibus_maximum
>  };
> 
> @@ -1481,13 +1482,24 @@ static void pci_devices_present_work(struct
> work_struct *work)
>                 put_pcichild(hpdev, hv_pcidev_ref_initial);
>         }
> 
> -       /* Tell the core to rescan bus because there may have been changes. */
> -       if (hbus->state == hv_pcibus_installed) {
> +       switch (hbus->state) {
> +       case hv_pcibus_installed:
> +               /*
> +                * Tell the core to rescan bus
> +                * because there may have been changes.
> +                */
>                 pci_lock_rescan_remove();
>                 pci_scan_child_bus(hbus->pci_bus);
>                 pci_unlock_rescan_remove();
> -       } else {
> +               break;
> +
> +       case hv_pcibus_init:
> +       case hv_pcibus_probed:
>                 survey_child_resources(hbus);
> +               break;
> +
> +       default:
> +               break;
>         }
> 
>         up(&hbus->enum_sem);
> @@ -2163,6 +2175,7 @@ static int hv_pci_probe(struct hv_device *hdev,
>         hbus = kzalloc(sizeof(*hbus), GFP_KERNEL);
>         if (!hbus)
>                 return -ENOMEM;
> +       hbus->state = hv_pcibus_init;
> 
>         /*
>          * The PCI bus "domain" is what is called "segment" in ACPI and
> @@ -2305,6 +2318,7 @@ static int hv_pci_remove(struct hv_device *hdev)
>                 pci_stop_root_bus(hbus->pci_bus);
>                 pci_remove_root_bus(hbus->pci_bus);
>                 pci_unlock_rescan_remove();
> +               hbus->state = hv_pcibus_removed;
>         }
> 
>         ret = hv_send_resources_released(hdev);
> --
> 1.8.5.6

Re: [PATCH 1/2 v3] pci-hyperv: properly handle pci bus remove

[Bjorn Helgaas]

On Mon, Oct 03, 2016 at 11:42:47PM -0700, Long Li wrote:
> From: Long Li <longli@microsoft.com>
> 
> hv_pci_devices_present is called in hv_pci_remove when we remove a PCI device from host (e.g. by disabling SRIOV on a device). In hv_pci_remove, the bus is already removed before the call, so we don't need to rescan the bus in the workqueue scheduled from hv_pci_devices_present. By introducing status hv_pcibus_removed, we can avoid this situation.
> 
> Signed-off-by: Long Li <longli@microsoft.com>
> Tested-by: Cathy Avery <cavery@redhat.com>
> Reported-by: Xiaofeng Wang <xiaofwan@redhat.com>

I need an ack from the Hyper-V maintainers.  I see acks for previous
versions, but I don't know whether you've changed things that would
invalidate those acks.  If the acks still apply, please include them
and repost these patches.

Also, please run "git log --oneline drivers/pci/host/pci-hyperv.c" and make
your subject line match the previous ones.

> ---
>  drivers/pci/host/pci-hyperv.c | 20 +++++++++++++++++---
>  1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
> index a8deeca..4a37598 100644
> --- a/drivers/pci/host/pci-hyperv.c
> +++ b/drivers/pci/host/pci-hyperv.c
> @@ -348,6 +348,7 @@ enum hv_pcibus_state {
>  	hv_pcibus_init = 0,
>  	hv_pcibus_probed,
>  	hv_pcibus_installed,
> +	hv_pcibus_removed,
>  	hv_pcibus_maximum
>  };
>  
> @@ -1481,13 +1482,24 @@ static void pci_devices_present_work(struct work_struct *work)
>  		put_pcichild(hpdev, hv_pcidev_ref_initial);
>  	}
>  
> -	/* Tell the core to rescan bus because there may have been changes. */
> -	if (hbus->state == hv_pcibus_installed) {
> +	switch (hbus->state) {
> +	case hv_pcibus_installed:
> +		/*
> +		 * Tell the core to rescan bus
> +		 * because there may have been changes.
> +		 */
>  		pci_lock_rescan_remove();
>  		pci_scan_child_bus(hbus->pci_bus);
>  		pci_unlock_rescan_remove();
> -	} else {
> +		break;
> +
> +	case hv_pcibus_init:
> +	case hv_pcibus_probed:
>  		survey_child_resources(hbus);
> +		break;
> +
> +	default:
> +		break;
>  	}
>  
>  	up(&hbus->enum_sem);
> @@ -2163,6 +2175,7 @@ static int hv_pci_probe(struct hv_device *hdev,
>  	hbus = kzalloc(sizeof(*hbus), GFP_KERNEL);
>  	if (!hbus)
>  		return -ENOMEM;
> +	hbus->state = hv_pcibus_init;
>  
>  	/*
>  	 * The PCI bus "domain" is what is called "segment" in ACPI and
> @@ -2305,6 +2318,7 @@ static int hv_pci_remove(struct hv_device *hdev)
>  		pci_stop_root_bus(hbus->pci_bus);
>  		pci_remove_root_bus(hbus->pci_bus);
>  		pci_unlock_rescan_remove();
> +		hbus->state = hv_pcibus_removed;
>  	}
>  
>  	ret = hv_send_resources_released(hdev);
> -- 
> 1.8.5.6
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

RE: [PATCH 1/2 v3] pci-hyperv: properly handle pci bus remove

[KY Srinivasan]

> -----Original Message-----
> From: Bjorn Helgaas [mailto:helgaas@kernel.org]
> Sent: Friday, November 11, 2016 1:04 PM
> To: Long Li <longli@microsoft.com>
> Cc: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
> <haiyangz@microsoft.com>; Bjorn Helgaas <bhelgaas@google.com>;
> devel@linuxdriverproject.org; linux-pci@vger.kernel.org; linux-
> kernel@vger.kernel.org; Long Li <longli@microsoft.com>
> Subject: Re: [PATCH 1/2 v3] pci-hyperv: properly handle pci bus remove
> 
> On Mon, Oct 03, 2016 at 11:42:47PM -0700, Long Li wrote:
> > From: Long Li <longli@microsoft.com>
> >
> > hv_pci_devices_present is called in hv_pci_remove when we remove a PCI
> device from host (e.g. by disabling SRIOV on a device). In hv_pci_remove,
> the bus is already removed before the call, so we don't need to rescan the
> bus in the workqueue scheduled from hv_pci_devices_present. By
> introducing status hv_pcibus_removed, we can avoid this situation.
> >
> > Signed-off-by: Long Li <longli@microsoft.com>
> > Tested-by: Cathy Avery <cavery@redhat.com>
> > Reported-by: Xiaofeng Wang <xiaofwan@redhat.com>

Acked-by: K. Y. Srinivasan <kys@microsoft.com>


> 
> I need an ack from the Hyper-V maintainers.  I see acks for previous
> versions, but I don't know whether you've changed things that would
> invalidate those acks.  If the acks still apply, please include them
> and repost these patches.
> 
> Also, please run "git log --oneline drivers/pci/host/pci-hyperv.c" and make
> your subject line match the previous ones.
> 
> > ---
> >  drivers/pci/host/pci-hyperv.c | 20 +++++++++++++++++---
> >  1 file changed, 17 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
> > index a8deeca..4a37598 100644
> > --- a/drivers/pci/host/pci-hyperv.c
> > +++ b/drivers/pci/host/pci-hyperv.c
> > @@ -348,6 +348,7 @@ enum hv_pcibus_state {
> >  	hv_pcibus_init = 0,
> >  	hv_pcibus_probed,
> >  	hv_pcibus_installed,
> > +	hv_pcibus_removed,
> >  	hv_pcibus_maximum
> >  };
> >
> > @@ -1481,13 +1482,24 @@ static void pci_devices_present_work(struct
> work_struct *work)
> >  		put_pcichild(hpdev, hv_pcidev_ref_initial);
> >  	}
> >
> > -	/* Tell the core to rescan bus because there may have been changes.
> */
> > -	if (hbus->state == hv_pcibus_installed) {
> > +	switch (hbus->state) {
> > +	case hv_pcibus_installed:
> > +		/*
> > +		 * Tell the core to rescan bus
> > +		 * because there may have been changes.
> > +		 */
> >  		pci_lock_rescan_remove();
> >  		pci_scan_child_bus(hbus->pci_bus);
> >  		pci_unlock_rescan_remove();
> > -	} else {
> > +		break;
> > +
> > +	case hv_pcibus_init:
> > +	case hv_pcibus_probed:
> >  		survey_child_resources(hbus);
> > +		break;
> > +
> > +	default:
> > +		break;
> >  	}
> >
> >  	up(&hbus->enum_sem);
> > @@ -2163,6 +2175,7 @@ static int hv_pci_probe(struct hv_device *hdev,
> >  	hbus = kzalloc(sizeof(*hbus), GFP_KERNEL);
> >  	if (!hbus)
> >  		return -ENOMEM;
> > +	hbus->state = hv_pcibus_init;
> >
> >  	/*
> >  	 * The PCI bus "domain" is what is called "segment" in ACPI and
> > @@ -2305,6 +2318,7 @@ static int hv_pci_remove(struct hv_device *hdev)
> >  		pci_stop_root_bus(hbus->pci_bus);
> >  		pci_remove_root_bus(hbus->pci_bus);
> >  		pci_unlock_rescan_remove();
> > +		hbus->state = hv_pcibus_removed;
> >  	}
> >
> >  	ret = hv_send_resources_released(hdev);
> > --
> > 1.8.5.6
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at
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RE: [PATCH 1/2 v3] pci-hyperv: properly handle pci bus remove

[Long Li]

Hi Bjorn

This patch is still pending. The patch has been ack'ed.

Do you want me to resend this patch?

Thanks

Long

> -----Original Message-----
> From: KY Srinivasan
> Sent: Friday, November 11, 2016 2:21 PM
> To: Bjorn Helgaas <helgaas@kernel.org>; Long Li <longli@microsoft.com>
> Cc: Haiyang Zhang <haiyangz@microsoft.com>; Bjorn Helgaas
> <bhelgaas@google.com>; devel@linuxdriverproject.org; linux-
> pci@vger.kernel.org; linux-kernel@vger.kernel.org; Long Li
> <longli@microsoft.com>
> Subject: RE: [PATCH 1/2 v3] pci-hyperv: properly handle pci bus remove
> 
> 
> 
> > -----Original Message-----
> > From: Bjorn Helgaas [mailto:helgaas@kernel.org]
> > Sent: Friday, November 11, 2016 1:04 PM
> > To: Long Li <longli@microsoft.com>
> > Cc: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
> > <haiyangz@microsoft.com>; Bjorn Helgaas <bhelgaas@google.com>;
> > devel@linuxdriverproject.org; linux-pci@vger.kernel.org; linux-
> > kernel@vger.kernel.org; Long Li <longli@microsoft.com>
> > Subject: Re: [PATCH 1/2 v3] pci-hyperv: properly handle pci bus remove
> >
> > On Mon, Oct 03, 2016 at 11:42:47PM -0700, Long Li wrote:
> > > From: Long Li <longli@microsoft.com>
> > >
> > > hv_pci_devices_present is called in hv_pci_remove when we remove a
> > > PCI
> > device from host (e.g. by disabling SRIOV on a device). In
> > hv_pci_remove, the bus is already removed before the call, so we don't
> > need to rescan the bus in the workqueue scheduled from
> > hv_pci_devices_present. By introducing status hv_pcibus_removed, we
> can avoid this situation.
> > >
> > > Signed-off-by: Long Li <longli@microsoft.com>
> > > Tested-by: Cathy Avery <cavery@redhat.com>
> > > Reported-by: Xiaofeng Wang <xiaofwan@redhat.com>
> 
> Acked-by: K. Y. Srinivasan <kys@microsoft.com>
> 
> 
> >
> > I need an ack from the Hyper-V maintainers.  I see acks for previous
> > versions, but I don't know whether you've changed things that would
> > invalidate those acks.  If the acks still apply, please include them
> > and repost these patches.
> >
> > Also, please run "git log --oneline drivers/pci/host/pci-hyperv.c" and
> > make your subject line match the previous ones.
> >
> > > ---
> > >  drivers/pci/host/pci-hyperv.c | 20 +++++++++++++++++---
> > >  1 file changed, 17 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/pci/host/pci-hyperv.c
> > > b/drivers/pci/host/pci-hyperv.c index a8deeca..4a37598 100644
> > > --- a/drivers/pci/host/pci-hyperv.c
> > > +++ b/drivers/pci/host/pci-hyperv.c
> > > @@ -348,6 +348,7 @@ enum hv_pcibus_state {
> > >  	hv_pcibus_init = 0,
> > >  	hv_pcibus_probed,
> > >  	hv_pcibus_installed,
> > > +	hv_pcibus_removed,
> > >  	hv_pcibus_maximum
> > >  };
> > >
> > > @@ -1481,13 +1482,24 @@ static void pci_devices_present_work(struct
> > work_struct *work)
> > >  		put_pcichild(hpdev, hv_pcidev_ref_initial);
> > >  	}
> > >
> > > -	/* Tell the core to rescan bus because there may have been changes.
> > */
> > > -	if (hbus->state == hv_pcibus_installed) {
> > > +	switch (hbus->state) {
> > > +	case hv_pcibus_installed:
> > > +		/*
> > > +		 * Tell the core to rescan bus
> > > +		 * because there may have been changes.
> > > +		 */
> > >  		pci_lock_rescan_remove();
> > >  		pci_scan_child_bus(hbus->pci_bus);
> > >  		pci_unlock_rescan_remove();
> > > -	} else {
> > > +		break;
> > > +
> > > +	case hv_pcibus_init:
> > > +	case hv_pcibus_probed:
> > >  		survey_child_resources(hbus);
> > > +		break;
> > > +
> > > +	default:
> > > +		break;
> > >  	}
> > >
> > >  	up(&hbus->enum_sem);
> > > @@ -2163,6 +2175,7 @@ static int hv_pci_probe(struct hv_device *hdev,
> > >  	hbus = kzalloc(sizeof(*hbus), GFP_KERNEL);
> > >  	if (!hbus)
> > >  		return -ENOMEM;
> > > +	hbus->state = hv_pcibus_init;
> > >
> > >  	/*
> > >  	 * The PCI bus "domain" is what is called "segment" in ACPI and @@
> > > -2305,6 +2318,7 @@ static int hv_pci_remove(struct hv_device *hdev)
> > >  		pci_stop_root_bus(hbus->pci_bus);
> > >  		pci_remove_root_bus(hbus->pci_bus);
> > >  		pci_unlock_rescan_remove();
> > > +		hbus->state = hv_pcibus_removed;
> > >  	}
> > >
> > >  	ret = hv_send_resources_released(hdev);
> > > --
> > > 1.8.5.6
> > >
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe linux-pci"
> > > in the body of a message to majordomo@vger.kernel.org More
> majordomo
> > > info at
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