[PATCHv2 1/2] PCI: Device driver reset notification

[PATCHv2 1/2] PCI: Device driver reset notification

[Keith Busch]

Notifies a pci device driver when its device's access is about to be
disabled for an impending reset attempt, then after the attempt completes
and device access is restored.

Signed-off-by: Keith Busch <keith.busch@intel.com>
---
v1 -> v2:

Call the reset notification in all cases before device access is disabled
and after device access is restored.

 drivers/pci/pci.c   |   21 +++++++++++++++++++++
 include/linux/pci.h |    3 +++
 2 files changed, 24 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7325d43..43d87b2 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3305,8 +3305,27 @@ static void pci_dev_unlock(struct pci_dev *dev)
 	pci_cfg_access_unlock(dev);
 }
 
+/**
+ * pci_reset_notify - notify device driver of reset
+ * @dev: device to be notified of reset
+ * @prepare: 'true' if device is about to be reset; 'false' if reset attempt
+ *           completed
+ *
+ * Must be called prior to device access being disabled and after device
+ * access is restored.
+ */
+static void pci_reset_notify(struct pci_dev *dev, bool prepare)
+{
+	const struct pci_error_handlers *err_handler =
+			dev->driver ? dev->driver->err_handler : NULL;
+	if (err_handler && err_handler->reset_notify)
+		err_handler->reset_notify(dev, prepare);
+}
+
 static void pci_dev_save_and_disable(struct pci_dev *dev)
 {
+	pci_reset_notify(dev, true);
+
 	/*
 	 * Wake-up device prior to save.  PM registers default to D0 after
 	 * reset and a simple register restore doesn't reliably return
@@ -3328,6 +3347,7 @@ static void pci_dev_save_and_disable(struct pci_dev *dev)
 static void pci_dev_restore(struct pci_dev *dev)
 {
 	pci_restore_state(dev);
+	pci_reset_notify(dev, false);
 }
 
 static int pci_dev_reset(struct pci_dev *dev, int probe)
@@ -3344,6 +3364,7 @@ static int pci_dev_reset(struct pci_dev *dev, int probe)
 
 	return rc;
 }
+
 /**
  * __pci_reset_function - reset a PCI device function
  * @dev: PCI device to reset
diff --git a/include/linux/pci.h b/include/linux/pci.h
index aab57b4..31c4309 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -603,6 +603,9 @@ struct pci_error_handlers {
 	/* PCI slot has been reset */
 	pci_ers_result_t (*slot_reset)(struct pci_dev *dev);
 
+	/* PCI function reset prepare or completed */
+	void (*reset_notify)(struct pci_dev *dev, bool prepare);
+
 	/* Device driver may resume normal operations */
 	void (*resume)(struct pci_dev *dev);
 };
-- 
1.7.10.4

[PATCHv2 2/2] NVMe: Implement PCI-e reset notification callback

[Keith Busch]

Quiesce and shutdown the device prior to reset, then restart the device
and resume IO after.

Signed-off-by: Keith Busch <keith.busch@intel.com>
---
v1 -> v2:

fixed compile warning for wrong data type in function (int -> bool).

 drivers/block/nvme-core.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index 7c64fa7..a842c71 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -2775,6 +2775,16 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	return result;
 }
 
+static void nvme_reset_notify(struct pci_dev *pdev, bool prepare)
+{
+       struct nvme_dev *dev = pci_get_drvdata(pdev);
+
+       if (prepare)
+               nvme_dev_shutdown(dev);
+       else
+               nvme_dev_resume(dev);
+}
+
 static void nvme_shutdown(struct pci_dev *pdev)
 {
 	struct nvme_dev *dev = pci_get_drvdata(pdev);
@@ -2839,6 +2849,7 @@ static const struct pci_error_handlers nvme_err_handler = {
 	.link_reset	= nvme_link_reset,
 	.slot_reset	= nvme_slot_reset,
 	.resume		= nvme_error_resume,
+	.reset_notify	= nvme_reset_notify,
 };
 
 /* Move to pci_ids.h later */
-- 
1.7.10.4

Re: [PATCHv2 1/2] PCI: Device driver reset notification

[Bjorn Helgaas]

On Fri, May 02, 2014 at 10:40:42AM -0600, Keith Busch wrote:
> Notifies a pci device driver when its device's access is about to be
> disabled for an impending reset attempt, then after the attempt completes
> and device access is restored.
> 
> Signed-off-by: Keith Busch <keith.busch@intel.com>

I applied both of these to my pci/hotplug branch for v3.16.  Let me know if
you want me to drop the NVMe patch and have it go via another tree.

Bjorn

> ---
> v1 -> v2:
> 
> Call the reset notification in all cases before device access is disabled
> and after device access is restored.
> 
>  drivers/pci/pci.c   |   21 +++++++++++++++++++++
>  include/linux/pci.h |    3 +++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 7325d43..43d87b2 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -3305,8 +3305,27 @@ static void pci_dev_unlock(struct pci_dev *dev)
>  	pci_cfg_access_unlock(dev);
>  }
>  
> +/**
> + * pci_reset_notify - notify device driver of reset
> + * @dev: device to be notified of reset
> + * @prepare: 'true' if device is about to be reset; 'false' if reset attempt
> + *           completed
> + *
> + * Must be called prior to device access being disabled and after device
> + * access is restored.
> + */
> +static void pci_reset_notify(struct pci_dev *dev, bool prepare)
> +{
> +	const struct pci_error_handlers *err_handler =
> +			dev->driver ? dev->driver->err_handler : NULL;
> +	if (err_handler && err_handler->reset_notify)
> +		err_handler->reset_notify(dev, prepare);
> +}
> +
>  static void pci_dev_save_and_disable(struct pci_dev *dev)
>  {
> +	pci_reset_notify(dev, true);
> +
>  	/*
>  	 * Wake-up device prior to save.  PM registers default to D0 after
>  	 * reset and a simple register restore doesn't reliably return
> @@ -3328,6 +3347,7 @@ static void pci_dev_save_and_disable(struct pci_dev *dev)
>  static void pci_dev_restore(struct pci_dev *dev)
>  {
>  	pci_restore_state(dev);
> +	pci_reset_notify(dev, false);
>  }
>  
>  static int pci_dev_reset(struct pci_dev *dev, int probe)
> @@ -3344,6 +3364,7 @@ static int pci_dev_reset(struct pci_dev *dev, int probe)
>  
>  	return rc;
>  }
> +
>  /**
>   * __pci_reset_function - reset a PCI device function
>   * @dev: PCI device to reset
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index aab57b4..31c4309 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -603,6 +603,9 @@ struct pci_error_handlers {
>  	/* PCI slot has been reset */
>  	pci_ers_result_t (*slot_reset)(struct pci_dev *dev);
>  
> +	/* PCI function reset prepare or completed */
> +	void (*reset_notify)(struct pci_dev *dev, bool prepare);
> +
>  	/* Device driver may resume normal operations */
>  	void (*resume)(struct pci_dev *dev);
>  };
> -- 
> 1.7.10.4
>