diff mbox series

[4/6] Revert "PCI: hv: Fix a timing issue which causes kdump to fail occasionally"

Message ID 20230328045122.25850-5-decui@microsoft.com
State New
Headers
Series pci-hyper: fix race condition bugs for fast device hotplug |

Commit Message

Dexuan Cui March 28, 2023, 4:51 a.m. UTC 
  This reverts commit d6af2ed29c7c1c311b96dac989dcb991e90ee195.

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 the
child "struct hv_pci_dev *hpdev" that is created earlier in
pci_devices_present_work() -> new_pcichild_device().

The commit d6af2ed29c7c was originally made in July 2020 for RHEL 7.7,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().

Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
 drivers/pci/controller/pci-hyperv.c | 71 ++++++++++++++---------------
 1 file changed, 34 insertions(+), 37 deletions(-)

Comments

Dexuan Cui March 28, 2023, 6:33 a.m. UTC | #1 
> From: Dexuan Cui <decui@microsoft.com>
> Sent: Monday, March 27, 2023 9:51 PM
> To: bhelgaas@google.com; davem@davemloft.net; Dexuan Cui
> <decui@microsoft.com>; edumazet@google.com; Haiyang Zhang
> <haiyangz@microsoft.com>; Jake Oshins <jakeo@microsoft.com>;
> kuba@kernel.org; kw@linux.com; KY Srinivasan <kys@microsoft.com>;
> leon@kernel.org; linux-pci@vger.kernel.org; lpieralisi@kernel.org; Michael
> Kelley (LINUX) <mikelley@microsoft.com>; pabeni@redhat.com;
> robh@kernel.org; saeedm@nvidia.com; wei.liu@kernel.org; Long Li
> <longli@microsoft.com>; boqun.feng@gmail.com
> Cc: linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-rdma@vger.kernel.org; netdev@vger.kernel.org
> Subject: [PATCH 4/6] Revert "PCI: hv: Fix a timing issue which causes kdump to
> fail occasionally"
> 
> This reverts commit d6af2ed29c7c1c311b96dac989dcb991e90ee195.
> 
> 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 the
> child "struct hv_pci_dev *hpdev" that is created earlier in
> pci_devices_present_work() -> new_pcichild_device().
> 
> 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().
> 
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> ---
>  drivers/pci/controller/pci-hyperv.c | 71 ++++++++++++++---------------
>  1 file changed, 34 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-hyperv.c
> b/drivers/pci/controller/pci-hyperv.c
> index 46df6d093d68..48feab095a14 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -3225,8 +3225,10 @@ static int hv_pci_enter_d0(struct hv_device *hdev)
>  	struct pci_bus_d0_entry *d0_entry;
>  	struct hv_pci_compl comp_pkt;
>  	struct pci_packet *pkt;
> +	bool retry = true;
>  	int ret;
> 
> +enter_d0_retry:
>  	/*
>  	 * Tell the host that the bus is ready to use, and moved into the
>  	 * powered-on state.  This includes telling the host which region
> @@ -3253,6 +3255,38 @@ static int hv_pci_enter_d0(struct hv_device *hdev)
>  	if (ret)
>  		goto exit;
> 
> +	/*
> +	 * In certain case (Kdump) the pci device of interest was
> +	 * not cleanly shut down and resource is still held on host
> +	 * side, the host could return invalid device status.
> +	 * We need to explicitly request host to release the resource
> +	 * and try to enter D0 again.
> +	 */
> +	if (comp_pkt.completion_status < 0 && retry) {
> +		retry = false;
> +
> +		dev_err(&hdev->device, "Retrying D0 Entry\n");
> +
> +		/*
> +		 * Hv_pci_bus_exit() calls hv_send_resource_released()
> +		 * to free up resources of its child devices.
> +		 * In the kdump kernel we need to set the
> +		 * wslot_res_allocated to 255 so it scans all child
> +		 * devices to release resources allocated in the
> +		 * normal kernel before panic happened.
> +		 */
> +		hbus->wslot_res_allocated = 255;
> +
> +		ret = hv_pci_bus_exit(hdev, true);
> +
> +		if (ret == 0) {
> +			kfree(pkt);
> +			goto enter_d0_retry;
> +		}
> +		dev_err(&hdev->device,
> +			"Retrying D0 failed with ret %d\n", ret);
> +	}
> +
>  	if (comp_pkt.completion_status < 0) {
>  		dev_err(&hdev->device,
>  			"PCI Pass-through VSP failed D0 Entry with status %x\n",
> @@ -3493,7 +3527,6 @@ static int hv_pci_probe(struct hv_device *hdev,
>  	struct hv_pcibus_device *hbus;
>  	u16 dom_req, dom;
>  	char *name;
> -	bool enter_d0_retry = true;
>  	int ret;
> 
>  	/*
> @@ -3633,47 +3666,11 @@ static int hv_pci_probe(struct hv_device *hdev,
>  	if (ret)
>  		goto free_fwnode;
> 
> -retry:
>  	ret = hv_pci_query_relations(hdev);
>  	if (ret)
>  		goto free_irq_domain;
> 
>  	ret = hv_pci_enter_d0(hdev);
> -	/*
> -	 * In certain case (Kdump) the pci device of interest was
> -	 * not cleanly shut down and resource is still held on host
> -	 * side, the host could return invalid device status.
> -	 * We need to explicitly request host to release the resource
> -	 * and try to enter D0 again.
> -	 * Since the hv_pci_bus_exit() call releases structures
> -	 * of all its child devices, we need to start the retry from
> -	 * hv_pci_query_relations() call, requesting host to send
> -	 * the synchronous child device relations message before this
> -	 * information is needed in hv_send_resources_allocated()
> -	 * call later.
> -	 */
> -	if (ret == -EPROTO && enter_d0_retry) {
> -		enter_d0_retry = false;
> -
> -		dev_err(&hdev->device, "Retrying D0 Entry\n");
> -
> -		/*
> -		 * Hv_pci_bus_exit() calls hv_send_resources_released()
> -		 * to free up resources of its child devices.
> -		 * In the kdump kernel we need to set the
> -		 * wslot_res_allocated to 255 so it scans all child
> -		 * devices to release resources allocated in the
> -		 * normal kernel before panic happened.
> -		 */
> -		hbus->wslot_res_allocated = 255;
> -		ret = hv_pci_bus_exit(hdev, true);
> -
> -		if (ret == 0)
> -			goto retry;
> -
> -		dev_err(&hdev->device,
> -			"Retrying D0 failed with ret %d\n", ret);
> -	}
>  	if (ret)
>  		goto free_irq_domain;
> 
> --
> 2.25.1

+ Wei Hu.
Wei Hu March 28, 2023, 12:46 p.m. UTC | #2 
> -----Original Message-----
> From: Dexuan Cui <decui@microsoft.com>
> Sent: Tuesday, March 28, 2023 2:33 PM
> To: bhelgaas@google.com; davem@davemloft.net; edumazet@google.com;
> Haiyang Zhang <haiyangz@microsoft.com>; Jake Oshins
> <jakeo@microsoft.com>; kuba@kernel.org; kw@linux.com; KY Srinivasan
> <kys@microsoft.com>; leon@kernel.org; linux-pci@vger.kernel.org;
> lpieralisi@kernel.org; Michael Kelley (LINUX) <mikelley@microsoft.com>;
> pabeni@redhat.com; robh@kernel.org; saeedm@nvidia.com;
> wei.liu@kernel.org; Long Li <longli@microsoft.com>; boqun.feng@gmail.com;
> Wei Hu <weh@microsoft.com>
> Cc: linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org; linux-
> rdma@vger.kernel.org; netdev@vger.kernel.org
> Subject: RE: [PATCH 4/6] Revert "PCI: hv: Fix a timing issue which causes
> kdump to fail occasionally"
> 
> > From: Dexuan Cui <decui@microsoft.com>
> > Sent: Monday, March 27, 2023 9:51 PM
> > To: bhelgaas@google.com; davem@davemloft.net; Dexuan Cui
> > <decui@microsoft.com>; edumazet@google.com; Haiyang Zhang
> > <haiyangz@microsoft.com>; Jake Oshins <jakeo@microsoft.com>;
> > kuba@kernel.org; kw@linux.com; KY Srinivasan <kys@microsoft.com>;
> > leon@kernel.org; linux-pci@vger.kernel.org; lpieralisi@kernel.org;
> > Michael Kelley (LINUX) <mikelley@microsoft.com>; pabeni@redhat.com;
> > robh@kernel.org; saeedm@nvidia.com; wei.liu@kernel.org; Long Li
> > <longli@microsoft.com>; boqun.feng@gmail.com
> > Cc: linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org;
> > linux-rdma@vger.kernel.org; netdev@vger.kernel.org
> > Subject: [PATCH 4/6] Revert "PCI: hv: Fix a timing issue which causes
> > kdump to fail occasionally"
> >
> > This reverts commit d6af2ed29c7c1c311b96dac989dcb991e90ee195.
> >
> > 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 the child "struct hv_pci_dev *hpdev" that is created earlier
> > in
> > pci_devices_present_work() -> new_pcichild_device().
> >
> > 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().
> >
> > Signed-off-by: Dexuan Cui <decui@microsoft.com>
> > ---
> >  drivers/pci/controller/pci-hyperv.c | 71
> > ++++++++++++++---------------
> >  1 file changed, 34 insertions(+), 37 deletions(-)
> >
> > diff --git a/drivers/pci/controller/pci-hyperv.c
> > b/drivers/pci/controller/pci-hyperv.c
> > index 46df6d093d68..48feab095a14 100644
> > --- a/drivers/pci/controller/pci-hyperv.c
> > +++ b/drivers/pci/controller/pci-hyperv.c
> > @@ -3225,8 +3225,10 @@ static int hv_pci_enter_d0(struct hv_device
> *hdev)
> >  	struct pci_bus_d0_entry *d0_entry;
> >  	struct hv_pci_compl comp_pkt;
> >  	struct pci_packet *pkt;
> > +	bool retry = true;
> >  	int ret;
> >
> > +enter_d0_retry:
> >  	/*
> >  	 * Tell the host that the bus is ready to use, and moved into the
> >  	 * powered-on state.  This includes telling the host which region @@
> > -3253,6 +3255,38 @@ static int hv_pci_enter_d0(struct hv_device *hdev)
> >  	if (ret)
> >  		goto exit;
> >
> > +	/*
> > +	 * In certain case (Kdump) the pci device of interest was
> > +	 * not cleanly shut down and resource is still held on host
> > +	 * side, the host could return invalid device status.
> > +	 * We need to explicitly request host to release the resource
> > +	 * and try to enter D0 again.
> > +	 */
> > +	if (comp_pkt.completion_status < 0 && retry) {
> > +		retry = false;
> > +
> > +		dev_err(&hdev->device, "Retrying D0 Entry\n");
> > +
> > +		/*
> > +		 * Hv_pci_bus_exit() calls hv_send_resource_released()
> > +		 * to free up resources of its child devices.
> > +		 * In the kdump kernel we need to set the
> > +		 * wslot_res_allocated to 255 so it scans all child
> > +		 * devices to release resources allocated in the
> > +		 * normal kernel before panic happened.
> > +		 */
> > +		hbus->wslot_res_allocated = 255;
> > +
> > +		ret = hv_pci_bus_exit(hdev, true);
> > +
> > +		if (ret == 0) {
> > +			kfree(pkt);
> > +			goto enter_d0_retry;
> > +		}
> > +		dev_err(&hdev->device,
> > +			"Retrying D0 failed with ret %d\n", ret);
> > +	}
> > +
> >  	if (comp_pkt.completion_status < 0) {
> >  		dev_err(&hdev->device,
> >  			"PCI Pass-through VSP failed D0 Entry with
> status %x\n", @@
> > -3493,7 +3527,6 @@ static int hv_pci_probe(struct hv_device *hdev,
> >  	struct hv_pcibus_device *hbus;
> >  	u16 dom_req, dom;
> >  	char *name;
> > -	bool enter_d0_retry = true;
> >  	int ret;
> >
> >  	/*
> > @@ -3633,47 +3666,11 @@ static int hv_pci_probe(struct hv_device *hdev,
> >  	if (ret)
> >  		goto free_fwnode;
> >
> > -retry:
> >  	ret = hv_pci_query_relations(hdev);
> >  	if (ret)
> >  		goto free_irq_domain;
> >
> >  	ret = hv_pci_enter_d0(hdev);
> > -	/*
> > -	 * In certain case (Kdump) the pci device of interest was
> > -	 * not cleanly shut down and resource is still held on host
> > -	 * side, the host could return invalid device status.
> > -	 * We need to explicitly request host to release the resource
> > -	 * and try to enter D0 again.
> > -	 * Since the hv_pci_bus_exit() call releases structures
> > -	 * of all its child devices, we need to start the retry from
> > -	 * hv_pci_query_relations() call, requesting host to send
> > -	 * the synchronous child device relations message before this
> > -	 * information is needed in hv_send_resources_allocated()
> > -	 * call later.
> > -	 */
> > -	if (ret == -EPROTO && enter_d0_retry) {
> > -		enter_d0_retry = false;
> > -
> > -		dev_err(&hdev->device, "Retrying D0 Entry\n");
> > -
> > -		/*
> > -		 * Hv_pci_bus_exit() calls hv_send_resources_released()
> > -		 * to free up resources of its child devices.
> > -		 * In the kdump kernel we need to set the
> > -		 * wslot_res_allocated to 255 so it scans all child
> > -		 * devices to release resources allocated in the
> > -		 * normal kernel before panic happened.
> > -		 */
> > -		hbus->wslot_res_allocated = 255;
> > -		ret = hv_pci_bus_exit(hdev, true);
> > -
> > -		if (ret == 0)
> > -			goto retry;
> > -
> > -		dev_err(&hdev->device,
> > -			"Retrying D0 failed with ret %d\n", ret);
> > -	}
> >  	if (ret)
> >  		goto free_irq_domain;
> >
> > --
> > 2.25.1

Looks good to me. Thanks for fixing this.

Wei
Wei Hu March 30, 2023, 5:17 a.m. UTC | #3 
> -----Original Message-----
> From: Dexuan Cui <decui@microsoft.com>
> Sent: Tuesday, March 28, 2023 2:33 PM
> To: bhelgaas@google.com; davem@davemloft.net; edumazet@google.com;
> Haiyang Zhang <haiyangz@microsoft.com>; Jake Oshins
> <jakeo@microsoft.com>; kuba@kernel.org; kw@linux.com; KY Srinivasan
> <kys@microsoft.com>; leon@kernel.org; linux-pci@vger.kernel.org;
> lpieralisi@kernel.org; Michael Kelley (LINUX) <mikelley@microsoft.com>;
> pabeni@redhat.com; robh@kernel.org; saeedm@nvidia.com;
> wei.liu@kernel.org; Long Li <longli@microsoft.com>; boqun.feng@gmail.com;
> Wei Hu <weh@microsoft.com>
> Cc: linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org; linux-
> rdma@vger.kernel.org; netdev@vger.kernel.org
> Subject: RE: [PATCH 4/6] Revert "PCI: hv: Fix a timing issue which causes
> kdump to fail occasionally"
> 
> > From: Dexuan Cui <decui@microsoft.com>
> > Sent: Monday, March 27, 2023 9:51 PM
> > To: bhelgaas@google.com; davem@davemloft.net; Dexuan Cui
> > <decui@microsoft.com>; edumazet@google.com; Haiyang Zhang
> > <haiyangz@microsoft.com>; Jake Oshins <jakeo@microsoft.com>;
> > kuba@kernel.org; kw@linux.com; KY Srinivasan <kys@microsoft.com>;
> > leon@kernel.org; linux-pci@vger.kernel.org; lpieralisi@kernel.org;
> > Michael Kelley (LINUX) <mikelley@microsoft.com>; pabeni@redhat.com;
> > robh@kernel.org; saeedm@nvidia.com; wei.liu@kernel.org; Long Li
> > <longli@microsoft.com>; boqun.feng@gmail.com
> > Cc: linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org;
> > linux-rdma@vger.kernel.org; netdev@vger.kernel.org
> > Subject: [PATCH 4/6] Revert "PCI: hv: Fix a timing issue which causes
> > kdump to fail occasionally"
> >
> > This reverts commit d6af2ed29c7c1c311b96dac989dcb991e90ee195.
> >
> > 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 the child "struct hv_pci_dev *hpdev" that is created earlier
> > in
> > pci_devices_present_work() -> new_pcichild_device().
> >
> > 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().
> >
> > Signed-off-by: Dexuan Cui <decui@microsoft.com>
> > ---
> >  drivers/pci/controller/pci-hyperv.c | 71
> > ++++++++++++++---------------
> >  1 file changed, 34 insertions(+), 37 deletions(-)
> >
> > diff --git a/drivers/pci/controller/pci-hyperv.c
> > b/drivers/pci/controller/pci-hyperv.c
> > index 46df6d093d68..48feab095a14 100644
> > --- a/drivers/pci/controller/pci-hyperv.c
> > +++ b/drivers/pci/controller/pci-hyperv.c
> > @@ -3225,8 +3225,10 @@ static int hv_pci_enter_d0(struct hv_device
> *hdev)
> >  	struct pci_bus_d0_entry *d0_entry;
> >  	struct hv_pci_compl comp_pkt;
> >  	struct pci_packet *pkt;
> > +	bool retry = true;
> >  	int ret;
> >
> > +enter_d0_retry:
> >  	/*
> >  	 * Tell the host that the bus is ready to use, and moved into the
> >  	 * powered-on state.  This includes telling the host which region @@
> > -3253,6 +3255,38 @@ static int hv_pci_enter_d0(struct hv_device *hdev)
> >  	if (ret)
> >  		goto exit;
> >
> > +	/*
> > +	 * In certain case (Kdump) the pci device of interest was
> > +	 * not cleanly shut down and resource is still held on host
> > +	 * side, the host could return invalid device status.
> > +	 * We need to explicitly request host to release the resource
> > +	 * and try to enter D0 again.
> > +	 */
> > +	if (comp_pkt.completion_status < 0 && retry) {
> > +		retry = false;
> > +
> > +		dev_err(&hdev->device, "Retrying D0 Entry\n");
> > +
> > +		/*
> > +		 * Hv_pci_bus_exit() calls hv_send_resource_released()
> > +		 * to free up resources of its child devices.
> > +		 * In the kdump kernel we need to set the
> > +		 * wslot_res_allocated to 255 so it scans all child
> > +		 * devices to release resources allocated in the
> > +		 * normal kernel before panic happened.
> > +		 */
> > +		hbus->wslot_res_allocated = 255;
> > +
> > +		ret = hv_pci_bus_exit(hdev, true);
> > +
> > +		if (ret == 0) {
> > +			kfree(pkt);
> > +			goto enter_d0_retry;
> > +		}
> > +		dev_err(&hdev->device,
> > +			"Retrying D0 failed with ret %d\n", ret);
> > +	}
> > +
> >  	if (comp_pkt.completion_status < 0) {
> >  		dev_err(&hdev->device,
> >  			"PCI Pass-through VSP failed D0 Entry with
> status %x\n", @@
> > -3493,7 +3527,6 @@ static int hv_pci_probe(struct hv_device *hdev,
> >  	struct hv_pcibus_device *hbus;
> >  	u16 dom_req, dom;
> >  	char *name;
> > -	bool enter_d0_retry = true;
> >  	int ret;
> >
> >  	/*
> > @@ -3633,47 +3666,11 @@ static int hv_pci_probe(struct hv_device *hdev,
> >  	if (ret)
> >  		goto free_fwnode;
> >
> > -retry:
> >  	ret = hv_pci_query_relations(hdev);
> >  	if (ret)
> >  		goto free_irq_domain;
> >
> >  	ret = hv_pci_enter_d0(hdev);
> > -	/*
> > -	 * In certain case (Kdump) the pci device of interest was
> > -	 * not cleanly shut down and resource is still held on host
> > -	 * side, the host could return invalid device status.
> > -	 * We need to explicitly request host to release the resource
> > -	 * and try to enter D0 again.
> > -	 * Since the hv_pci_bus_exit() call releases structures
> > -	 * of all its child devices, we need to start the retry from
> > -	 * hv_pci_query_relations() call, requesting host to send
> > -	 * the synchronous child device relations message before this
> > -	 * information is needed in hv_send_resources_allocated()
> > -	 * call later.
> > -	 */
> > -	if (ret == -EPROTO && enter_d0_retry) {
> > -		enter_d0_retry = false;
> > -
> > -		dev_err(&hdev->device, "Retrying D0 Entry\n");
> > -
> > -		/*
> > -		 * Hv_pci_bus_exit() calls hv_send_resources_released()
> > -		 * to free up resources of its child devices.
> > -		 * In the kdump kernel we need to set the
> > -		 * wslot_res_allocated to 255 so it scans all child
> > -		 * devices to release resources allocated in the
> > -		 * normal kernel before panic happened.
> > -		 */
> > -		hbus->wslot_res_allocated = 255;
> > -		ret = hv_pci_bus_exit(hdev, true);
> > -
> > -		if (ret == 0)
> > -			goto retry;
> > -
> > -		dev_err(&hdev->device,
> > -			"Retrying D0 failed with ret %d\n", ret);
> > -	}
> >  	if (ret)
> >  		goto free_irq_domain;
> >
> > --
> > 2.25.1
>

Acked-by: Wei Hu <weh@microsoft.com>
diff mbox series

Patch

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 46df6d093d68..48feab095a14 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -3225,8 +3225,10 @@  static int hv_pci_enter_d0(struct hv_device *hdev)
 	struct pci_bus_d0_entry *d0_entry;
 	struct hv_pci_compl comp_pkt;
 	struct pci_packet *pkt;
+	bool retry = true;
 	int ret;
 
+enter_d0_retry:
 	/*
 	 * Tell the host that the bus is ready to use, and moved into the
 	 * powered-on state.  This includes telling the host which region
@@ -3253,6 +3255,38 @@  static int hv_pci_enter_d0(struct hv_device *hdev)
 	if (ret)
 		goto exit;
 
+	/*
+	 * In certain case (Kdump) the pci device of interest was
+	 * not cleanly shut down and resource is still held on host
+	 * side, the host could return invalid device status.
+	 * We need to explicitly request host to release the resource
+	 * and try to enter D0 again.
+	 */
+	if (comp_pkt.completion_status < 0 && retry) {
+		retry = false;
+
+		dev_err(&hdev->device, "Retrying D0 Entry\n");
+
+		/*
+		 * Hv_pci_bus_exit() calls hv_send_resource_released()
+		 * to free up resources of its child devices.
+		 * In the kdump kernel we need to set the
+		 * wslot_res_allocated to 255 so it scans all child
+		 * devices to release resources allocated in the
+		 * normal kernel before panic happened.
+		 */
+		hbus->wslot_res_allocated = 255;
+
+		ret = hv_pci_bus_exit(hdev, true);
+
+		if (ret == 0) {
+			kfree(pkt);
+			goto enter_d0_retry;
+		}
+		dev_err(&hdev->device,
+			"Retrying D0 failed with ret %d\n", ret);
+	}
+
 	if (comp_pkt.completion_status < 0) {
 		dev_err(&hdev->device,
 			"PCI Pass-through VSP failed D0 Entry with status %x\n",
@@ -3493,7 +3527,6 @@  static int hv_pci_probe(struct hv_device *hdev,
 	struct hv_pcibus_device *hbus;
 	u16 dom_req, dom;
 	char *name;
-	bool enter_d0_retry = true;
 	int ret;
 
 	/*
@@ -3633,47 +3666,11 @@  static int hv_pci_probe(struct hv_device *hdev,
 	if (ret)
 		goto free_fwnode;
 
-retry:
 	ret = hv_pci_query_relations(hdev);
 	if (ret)
 		goto free_irq_domain;
 
 	ret = hv_pci_enter_d0(hdev);
-	/*
-	 * In certain case (Kdump) the pci device of interest was
-	 * not cleanly shut down and resource is still held on host
-	 * side, the host could return invalid device status.
-	 * We need to explicitly request host to release the resource
-	 * and try to enter D0 again.
-	 * Since the hv_pci_bus_exit() call releases structures
-	 * of all its child devices, we need to start the retry from
-	 * hv_pci_query_relations() call, requesting host to send
-	 * the synchronous child device relations message before this
-	 * information is needed in hv_send_resources_allocated()
-	 * call later.
-	 */
-	if (ret == -EPROTO && enter_d0_retry) {
-		enter_d0_retry = false;
-
-		dev_err(&hdev->device, "Retrying D0 Entry\n");
-
-		/*
-		 * Hv_pci_bus_exit() calls hv_send_resources_released()
-		 * to free up resources of its child devices.
-		 * In the kdump kernel we need to set the
-		 * wslot_res_allocated to 255 so it scans all child
-		 * devices to release resources allocated in the
-		 * normal kernel before panic happened.
-		 */
-		hbus->wslot_res_allocated = 255;
-		ret = hv_pci_bus_exit(hdev, true);
-
-		if (ret == 0)
-			goto retry;
-
-		dev_err(&hdev->device,
-			"Retrying D0 failed with ret %d\n", ret);
-	}
 	if (ret)
 		goto free_irq_domain;