powerpc/eeh: Rework eeh_ops->probe()

With the EEH early probe now being pseries specific there's no need for
eeh_ops->probe() to take a pci_dn. Instead, we can make it take a pci_dev
and use the probe function to map a pci_dev to an eeh_dev. This allows
the platform to implement it's own method for finding (or creating) an
eeh_dev for a given pci_dev which also removes a use of pci_dn in
generic EEH code.

This patch also renames eeh_device_add_late() to eeh_device_probe(). This
better reflects what it does does and removes the last vestiges of the
early/late EEH probe split.

Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200306073904.4737-6-oohall@gmail.com

1 files changed, 23 insertions, 21 deletions

diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index 55d3ef6e5b9c..7cdcb413bb44 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -1107,35 +1107,43 @@ static int eeh_init(void)
 core_initcall_sync(eeh_init);
 
 /**
- * eeh_add_device_late - Perform EEH initialization for the indicated pci device
+ * eeh_probe_device() - Perform EEH initialization for the indicated pci device
  * @dev: pci device for which to set up EEH
  *
  * This routine must be used to complete EEH initialization for PCI
  * devices that were added after system boot (e.g. hotplug, dlpar).
  */
-void eeh_add_device_late(struct pci_dev *dev)
+void eeh_probe_device(struct pci_dev *dev)
 {
-	struct pci_dn *pdn;
 	struct eeh_dev *edev;
 
-	if (!dev)
+	pr_debug("EEH: Adding device %s\n", pci_name(dev));
+
+	/*
+	 * pci_dev_to_eeh_dev() can only work if eeh_probe_dev() was
+	 * already called for this device.
+	 */
+	if (WARN_ON_ONCE(pci_dev_to_eeh_dev(dev))) {
+		pci_dbg(dev, "Already bound to an eeh_dev!\n");
 		return;
+	}
 
-	pdn = pci_get_pdn_by_devfn(dev->bus, dev->devfn);
-	edev = pdn_to_eeh_dev(pdn);
-	eeh_edev_dbg(edev, "Adding device\n");
-	if (edev->pdev == dev) {
-		eeh_edev_dbg(edev, "Device already referenced!\n");
+	edev = eeh_ops->probe(dev);
+	if (!edev) {
+		pr_debug("EEH: Adding device failed\n");
 		return;
 	}
 
 	/*
-	 * The EEH cache might not be removed correctly because of
-	 * unbalanced kref to the device during unplug time, which
-	 * relies on pcibios_release_device(). So we have to remove
-	 * that here explicitly.
+	 * FIXME: We rely on pcibios_release_device() to remove the
+	 * existing EEH state. The release function is only called if
+	 * the pci_dev's refcount drops to zero so if something is
+	 * keeping a ref to a device (e.g. a filesystem) we need to
+	 * remove the old EEH state.
+	 *
+	 * FIXME: HEY MA, LOOK AT ME, NO LOCKING!
 	 */
-	if (edev->pdev) {
+	if (edev->pdev && edev->pdev != dev) {
 		eeh_rmv_from_parent_pe(edev);
 		eeh_addr_cache_rmv_dev(edev->pdev);
 		eeh_sysfs_remove_device(edev->pdev);
@@ -1146,17 +1154,11 @@ void eeh_add_device_late(struct pci_dev *dev)
 		 * into error handler afterwards.
 		 */
 		edev->mode |= EEH_DEV_NO_HANDLER;
-
-		edev->pdev = NULL;
-		dev->dev.archdata.edev = NULL;
 	}
 
-	if (eeh_has_flag(EEH_PROBE_MODE_DEV))
-		eeh_ops->probe(pdn, NULL);
-
+	/* bind the pdev and the edev together */
 	edev->pdev = dev;
 	dev->dev.archdata.edev = edev;
-
 	eeh_addr_cache_insert_dev(dev);
 	eeh_sysfs_add_device(dev);
 }