Commit 05793884 authored by Niklas Schnelle's avatar Niklas Schnelle Committed by Vasily Gorbik
Browse files

s390/pci: Pull search for parent PF out of zpci_iov_setup_virtfn() 



This creates a new zpci_iov_find_parent_pf() function which a future
commit can use to find if a VF has a configured parent PF. Use
zdev->rid instead of zdev->devfn such that the new function can be used
before it has been decided if the RID will be exposed and zdev->devfn is
set. Also handle the hypotheical case that the RID is not available but
there is an otherwise matching zbus.

Fixes: 25f39d3d ("s390/pci: Ignore RID for isolated VFs")
Cc: stable@vger.kernel.org
Reviewed-by: default avatarHalil Pasic <pasic@linux.ibm.com>
Signed-off-by: default avatarNiklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent 6166caf3

arch/s390/pci/pci_iov.c

+42 −14
Original line number Diff line number Diff line
@@ -60,18 +60,35 @@ static int zpci_iov_link_virtfn(struct pci_dev *pdev, struct pci_dev *virtfn, in 
	return 0;

}



int zpci_iov_setup_virtfn(struct zpci_bus *zbus, struct pci_dev *virtfn, int vfn)

/**

 * zpci_iov_find_parent_pf - Find the parent PF, if any, of the given function

 * @zbus:	The bus that the PCI function is on, or would be added on

 * @zdev:	The PCI function

 *

 * Finds the parent PF, if it exists and is configured, of the given PCI function

 * and increments its refcount. Th PF is searched for on the provided bus so the

 * caller has to ensure that this is the correct bus to search. This function may

 * be used before adding the PCI function to a zbus.

 *

 * Return: Pointer to the struct pci_dev of the parent PF or NULL if it not

 * found. If the function is not a VF or has no RequesterID information,

 * NULL is returned as well.

 */

static struct pci_dev *zpci_iov_find_parent_pf(struct zpci_bus *zbus, struct zpci_dev *zdev)

{

	int i, cand_devfn;

	struct zpci_dev *zdev;

	int i, vfid, devfn, cand_devfn;

	struct pci_dev *pdev;

	int vfid = vfn - 1; /* Linux' vfid's start at 0 vfn at 1*/

	int rc = 0;



	if (!zbus->multifunction)

		return 0;



	/* If the parent PF for the given VF is also configured in the

		return NULL;

	/* Non-VFs and VFs without RID available don't have a parent */

	if (!zdev->vfn || !zdev->rid_available)

		return NULL;

	/* Linux vfid starts at 0 vfn at 1 */

	vfid = zdev->vfn - 1;

	devfn = zdev->rid & ZPCI_RID_MASK_DEVFN;

	/*

	 * If the parent PF for the given VF is also configured in the

	 * instance, it must be on the same zbus.

	 * We can then identify the parent PF by checking what

	 * devfn the VF would have if it belonged to that PF using the PF's
@@ -85,15 +102,26 @@ int zpci_iov_setup_virtfn(struct zpci_bus *zbus, struct pci_dev *virtfn, int vfn 
			if (!pdev)

				continue;

			cand_devfn = pci_iov_virtfn_devfn(pdev, vfid);

			if (cand_devfn == virtfn->devfn) {

				rc = zpci_iov_link_virtfn(pdev, virtfn, vfid);

			if (cand_devfn == devfn)

				return pdev;

			/* balance pci_get_slot() */

			pci_dev_put(pdev);

				break;

		}

			/* balance pci_get_slot() */

			pci_dev_put(pdev);

	}

	return NULL;

}



int zpci_iov_setup_virtfn(struct zpci_bus *zbus, struct pci_dev *virtfn, int vfn)

{

	struct zpci_dev *zdev = to_zpci(virtfn);

	struct pci_dev *pdev_pf;

	int rc = 0;



	pdev_pf = zpci_iov_find_parent_pf(zbus, zdev);

	if (pdev_pf) {

		/* Linux' vfids start at 0 while zdev->vfn starts at 1 */

		rc = zpci_iov_link_virtfn(pdev_pf, virtfn, zdev->vfn - 1);

		pci_dev_put(pdev_pf);

	}

	return rc;

}