[v5,06/11] PCI: Expose reset type to users of pci_reset_bus()

Message ID 20181011045008.32212-6-okaya@kernel.org
State Superseded
Delegated to: Bjorn Helgaas
Headers show
Series
  • [v5,01/11] PCI: Expose reset_type to users of __pci_reset_function_locked()
Related show

Commit Message

Sinan Kaya Oct. 11, 2018, 4:49 a.m.
Looking to have more control between the users of the API vs. what the API
can do internally. The new reset_type tells the PCI core about the bounds
of the request.

Signed-off-by: Sinan Kaya <okaya@kernel.org>
---
 drivers/pci/pci.c           | 17 ++++++++++++++---
 drivers/vfio/pci/vfio_pci.c |  6 ++++--
 include/linux/pci.h         |  2 +-
 3 files changed, 19 insertions(+), 6 deletions(-)

Comments

Alex Williamson Oct. 11, 2018, 3:33 p.m. | #1
On Thu, 11 Oct 2018 04:49:58 +0000
Sinan Kaya <okaya@kernel.org> wrote:

> Looking to have more control between the users of the API vs. what the API
> can do internally. The new reset_type tells the PCI core about the bounds
> of the request.
> 
> Signed-off-by: Sinan Kaya <okaya@kernel.org>
> ---
>  drivers/pci/pci.c           | 17 ++++++++++++++---
>  drivers/vfio/pci/vfio_pci.c |  6 ++++--
>  include/linux/pci.h         |  2 +-
>  3 files changed, 19 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index a1a7dd6988be..a3a1c2a5e0cf 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -5236,13 +5236,24 @@ static int __pci_reset_bus(struct pci_bus *bus)
>  /**
>   * pci_reset_bus - Try to reset a PCI bus
>   * @pdev: top level PCI device to reset via slot/bus
> + * @reset_type: resets to try
>   *
>   * Same as above except return -EAGAIN if the bus cannot be locked
>   */
> -int pci_reset_bus(struct pci_dev *pdev)
> +int pci_reset_bus(struct pci_dev *pdev, u32 reset_type)
>  {
> -	return (!pci_probe_reset_slot(pdev->slot)) ?
> -	    __pci_reset_slot(pdev->slot) : __pci_reset_bus(pdev->bus);
> +	if ((reset_type & PCI_RESET_LINK) == PCI_RESET_LINK)
> +		return (!pci_probe_reset_slot(pdev->slot)) ?
> +				__pci_reset_slot(pdev->slot) :
> +				__pci_reset_bus(pdev->bus);
> +
> +	if ((reset_type & PCI_RESET_BUS) == PCI_RESET_BUS)
> +		return __pci_reset_bus(pdev->bus);
> +
> +	if ((reset_type & PCI_RESET_SLOT) == PCI_RESET_SLOT)
> +		return __pci_reset_slot(pdev->slot);
> +
> +	return -EINVAL;


Having three cases here still seems strange.  The below still has some
duplicate probing but doesn't it do the same thing with less redundancy?

if ((reset_type & PCI_RESET_SLOT) && !pci_probe_reset_slot(pdev->slot))
	return __pci_reset_slot(pdev->slot);

if ((reset_type & PCI_RESET_BUS) && !pci_probe_reset_bus(pdev->slot))
	return __pci_reset_bus(pdev->bus);

return -EINVAL;

Thanks,
Alex

>  }
>  EXPORT_SYMBOL_GPL(pci_reset_bus);
>  
> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> index fe7ada997c51..0e80c72b1eaa 100644
> --- a/drivers/vfio/pci/vfio_pci.c
> +++ b/drivers/vfio/pci/vfio_pci.c
> @@ -1015,7 +1015,8 @@ static long vfio_pci_ioctl(void *device_data,
>  						    &info, slot);
>  		if (!ret)
>  			/* User has access, do the reset */
> -			ret = pci_reset_bus(vdev->pdev);
> +			ret = pci_reset_bus(vdev->pdev,
> +				slot ? PCI_RESET_SLOT :	PCI_RESET_BUS);
>  
>  hot_reset_release:
>  		for (i--; i >= 0; i--)
> @@ -1390,7 +1391,8 @@ static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev)
>  	}
>  
>  	if (needs_reset)
> -		ret = pci_reset_bus(vdev->pdev);
> +		ret = pci_reset_bus(vdev->pdev,
> +				slot ? PCI_RESET_SLOT :	PCI_RESET_BUS);
>  
>  put_devs:
>  	for (i = 0; i < devs.cur_index; i++) {
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 1c120cf00dd8..cf1e847ea02e 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1171,7 +1171,7 @@ int pci_reset_function_locked(struct pci_dev *dev, u32 reset_type);
>  int pci_try_reset_function(struct pci_dev *dev, u32 reset_type);
>  int pci_probe_reset_slot(struct pci_slot *slot);
>  int pci_probe_reset_bus(struct pci_bus *bus);
> -int pci_reset_bus(struct pci_dev *dev);
> +int pci_reset_bus(struct pci_dev *dev, u32 reset_type);
>  void pci_reset_secondary_bus(struct pci_dev *dev);
>  void pcibios_reset_secondary_bus(struct pci_dev *dev);
>  void pci_update_resource(struct pci_dev *dev, int resno);
Sinan Kaya Oct. 11, 2018, 3:36 p.m. | #2
On 10/11/2018 11:33 AM, Alex Williamson wrote:
> Having three cases here still seems strange.  The below still has some
> duplicate probing but doesn't it do the same thing with less redundancy?
> 
> if ((reset_type & PCI_RESET_SLOT) && !pci_probe_reset_slot(pdev->slot))
> 	return __pci_reset_slot(pdev->slot);
> 
> if ((reset_type & PCI_RESET_BUS) && !pci_probe_reset_bus(pdev->slot))
> 	return __pci_reset_bus(pdev->bus);

I agree this looks cleaner. I'll fold it in on the next rev.

Patch

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index a1a7dd6988be..a3a1c2a5e0cf 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5236,13 +5236,24 @@  static int __pci_reset_bus(struct pci_bus *bus)
 /**
  * pci_reset_bus - Try to reset a PCI bus
  * @pdev: top level PCI device to reset via slot/bus
+ * @reset_type: resets to try
  *
  * Same as above except return -EAGAIN if the bus cannot be locked
  */
-int pci_reset_bus(struct pci_dev *pdev)
+int pci_reset_bus(struct pci_dev *pdev, u32 reset_type)
 {
-	return (!pci_probe_reset_slot(pdev->slot)) ?
-	    __pci_reset_slot(pdev->slot) : __pci_reset_bus(pdev->bus);
+	if ((reset_type & PCI_RESET_LINK) == PCI_RESET_LINK)
+		return (!pci_probe_reset_slot(pdev->slot)) ?
+				__pci_reset_slot(pdev->slot) :
+				__pci_reset_bus(pdev->bus);
+
+	if ((reset_type & PCI_RESET_BUS) == PCI_RESET_BUS)
+		return __pci_reset_bus(pdev->bus);
+
+	if ((reset_type & PCI_RESET_SLOT) == PCI_RESET_SLOT)
+		return __pci_reset_slot(pdev->slot);
+
+	return -EINVAL;
 }
 EXPORT_SYMBOL_GPL(pci_reset_bus);
 
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index fe7ada997c51..0e80c72b1eaa 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -1015,7 +1015,8 @@  static long vfio_pci_ioctl(void *device_data,
 						    &info, slot);
 		if (!ret)
 			/* User has access, do the reset */
-			ret = pci_reset_bus(vdev->pdev);
+			ret = pci_reset_bus(vdev->pdev,
+				slot ? PCI_RESET_SLOT :	PCI_RESET_BUS);
 
 hot_reset_release:
 		for (i--; i >= 0; i--)
@@ -1390,7 +1391,8 @@  static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev)
 	}
 
 	if (needs_reset)
-		ret = pci_reset_bus(vdev->pdev);
+		ret = pci_reset_bus(vdev->pdev,
+				slot ? PCI_RESET_SLOT :	PCI_RESET_BUS);
 
 put_devs:
 	for (i = 0; i < devs.cur_index; i++) {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 1c120cf00dd8..cf1e847ea02e 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1171,7 +1171,7 @@  int pci_reset_function_locked(struct pci_dev *dev, u32 reset_type);
 int pci_try_reset_function(struct pci_dev *dev, u32 reset_type);
 int pci_probe_reset_slot(struct pci_slot *slot);
 int pci_probe_reset_bus(struct pci_bus *bus);
-int pci_reset_bus(struct pci_dev *dev);
+int pci_reset_bus(struct pci_dev *dev, u32 reset_type);
 void pci_reset_secondary_bus(struct pci_dev *dev);
 void pcibios_reset_secondary_bus(struct pci_dev *dev);
 void pci_update_resource(struct pci_dev *dev, int resno);