6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
commit 05793884a1f30509e477de9da233ab73584b1c8c upstream.
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: 25f39d3dcb48 ("s390/pci: Ignore RID for isolated VFs")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
Signed-off-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/pci/pci_iov.c | 56 ++++++++++++++++++++++++++++++-----------
1 file changed, 42 insertions(+), 14 deletions(-)
diff --git a/arch/s390/pci/pci_iov.c b/arch/s390/pci/pci_iov.c
index ead062bf2b41..c7fdf5e79b3c 100644
--- a/arch/s390/pci/pci_iov.c
+++ b/arch/s390/pci/pci_iov.c
@@ -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);
- /* balance pci_get_slot() */
- pci_dev_put(pdev);
- break;
- }
+ if (cand_devfn == devfn)
+ return pdev;
/* 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;
}
--
2.48.1
