[SRU][F][G][PATCH 1/2] PCI/IOV: Introduce pci_iov_sysfs_link() function

[Kleber Souza]

On 2020-06-02 11:45, frank.heimes at canonical.com wrote:
> From: Niklas Schnelle <schnelle at linux.ibm.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1879704
> 
> Currently pci_iov_add_virtfn() scans the SR-IOV BARs, adds the VF to the
> bus and also creates the sysfs links between the newly added VF and its
> parent PF.
> 
> With pdev->no_vf_scan fencing off the entire pci_iov_add_virtfn() call
> s390 as the sole pdev->no_vf_scan user thus ends up missing these sysfs
> links which are required for example by QEMU/libvirt.
> 
> Instead of duplicating the code refactor pci_iov_add_virtfn() to make
> sysfs link creation callable separately.
> 
> Signed-off-by: Niklas Schnelle <schnelle at linux.ibm.com>
> Acked-by: Bjorn Helgaas <bhelgaas at google.com>
> Reviewed-by: Pierre Morel <pmorel at linux.ibm.com>
> [ schnelle: Link: https://lore.kernel.org/r/20200506154139.90609-1-schnelle@linux.ibm.com ]
> Signed-off-by: Vasily Gorbik <gor at linux.ibm.com>
> (cherry picked from commit a1ceea67f2e5b73cebd456e7fb463b3052bc6344)

This patch has not been merged into Linus' tree yet, so the above line
should be:

(cherry picked from commit a1ceea67f2e5b73cebd456e7fb463b3052bc6344 linux-next)

> Signed-off-by: Frank Heimes <frank.heimes at canonical.com>
> ---
>  drivers/pci/iov.c   | 36 +++++++++++++++++++++++++-----------
>  include/linux/pci.h |  8 ++++++++
>  2 files changed, 33 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> index deec9f9e0b61..9c778671db99 100644
> --- a/drivers/pci/iov.c
> +++ b/drivers/pci/iov.c
> @@ -134,12 +134,35 @@ static void pci_read_vf_config_common(struct pci_dev *virtfn)
>  			     &physfn->sriov->subsystem_device);
>  }
>  
> +int pci_iov_sysfs_link(struct pci_dev *dev,
> +		struct pci_dev *virtfn, int id)
> +{
> +	char buf[VIRTFN_ID_LEN];
> +	int rc;
> +
> +	sprintf(buf, "virtfn%u", id);
> +	rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);
> +	if (rc)
> +		goto failed;
> +	rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn");
> +	if (rc)
> +		goto failed1;
> +
> +	kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE);
> +
> +	return 0;
> +
> +failed1:
> +	sysfs_remove_link(&dev->dev.kobj, buf);
> +failed:
> +	return rc;
> +}
> +
>  int pci_iov_add_virtfn(struct pci_dev *dev, int id)
>  {
>  	int i;
>  	int rc = -ENOMEM;
>  	u64 size;
> -	char buf[VIRTFN_ID_LEN];
>  	struct pci_dev *virtfn;
>  	struct resource *res;
>  	struct pci_sriov *iov = dev->sriov;
> @@ -183,23 +206,14 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id)
>  	}
>  
>  	pci_device_add(virtfn, virtfn->bus);
> -
> -	sprintf(buf, "virtfn%u", id);
> -	rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);
> +	rc = pci_iov_sysfs_link(dev, virtfn, id);
>  	if (rc)
>  		goto failed1;
> -	rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn");
> -	if (rc)
> -		goto failed2;
> -
> -	kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE);
>  
>  	pci_bus_add_device(virtfn);
>  
>  	return 0;
>  
> -failed2:
> -	sysfs_remove_link(&dev->dev.kobj, buf);
>  failed1:
>  	pci_stop_and_remove_bus_device(virtfn);
>  	pci_dev_put(dev);
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 9c39a9ef2829..66e914d7f6c6 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -2049,6 +2049,8 @@ int pci_iov_virtfn_devfn(struct pci_dev *dev, int id);
>  
>  int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn);
>  void pci_disable_sriov(struct pci_dev *dev);
> +
> +int pci_iov_sysfs_link(struct pci_dev *dev, struct pci_dev *virtfn, int id);
>  int pci_iov_add_virtfn(struct pci_dev *dev, int id);
>  void pci_iov_remove_virtfn(struct pci_dev *dev, int id);
>  int pci_num_vf(struct pci_dev *dev);
> @@ -2074,6 +2076,12 @@ static inline int pci_iov_virtfn_devfn(struct pci_dev *dev, int id)
>  }
>  static inline int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
>  { return -ENODEV; }
> +
> +static inline int pci_iov_sysfs_link(struct pci_dev *dev,
> +				     struct pci_dev *virtfn, int id)
> +{
> +	return -ENODEV;
> +}
>  static inline int pci_iov_add_virtfn(struct pci_dev *dev, int id)
>  {
>  	return -ENOSYS;
>