linux/arch/powerpc/kernel/pci-hotplug.c
Sam Bobroff 466381ecdc powerpc/eeh: Release EEH device state synchronously
EEH device state is currently removed (by eeh_remove_device()) during
the device release handler, which is invoked as the device's reference
count drops to zero. This may take some time, or forever, as other
threads may hold references.

However, the PCI device state is released synchronously by
pci_stop_and_remove_bus_device(). This mismatch causes problems, for
example the device may be re-discovered as a new device before the
release handler has been called, leaving the PCI and EEH state
mismatched.

So instead, call eeh_remove_device() from the bus device removal
handlers, which are called synchronously in the removal path.

Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0a1f5105d3a33b1c090bba31de63eb0cdd25de7b.1588045502.git.sbobroff@linux.ibm.com
2020-05-18 21:58:44 +10:00

149 lines
4.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Derived from "arch/powerpc/platforms/pseries/pci_dlpar.c"
*
* Copyright (C) 2003 Linda Xie <lxie@us.ibm.com>
* Copyright (C) 2005 International Business Machines
*
* Updates, 2005, John Rose <johnrose@austin.ibm.com>
* Updates, 2005, Linas Vepstas <linas@austin.ibm.com>
* Updates, 2013, Gavin Shan <shangw@linux.vnet.ibm.com>
*/
#include <linux/pci.h>
#include <linux/export.h>
#include <asm/pci-bridge.h>
#include <asm/ppc-pci.h>
#include <asm/firmware.h>
#include <asm/eeh.h>
static struct pci_bus *find_bus_among_children(struct pci_bus *bus,
struct device_node *dn)
{
struct pci_bus *child = NULL;
struct pci_bus *tmp;
if (pci_bus_to_OF_node(bus) == dn)
return bus;
list_for_each_entry(tmp, &bus->children, node) {
child = find_bus_among_children(tmp, dn);
if (child)
break;
}
return child;
}
struct pci_bus *pci_find_bus_by_node(struct device_node *dn)
{
struct pci_dn *pdn = PCI_DN(dn);
if (!pdn || !pdn->phb || !pdn->phb->bus)
return NULL;
return find_bus_among_children(pdn->phb->bus, dn);
}
EXPORT_SYMBOL_GPL(pci_find_bus_by_node);
/**
* pcibios_release_device - release PCI device
* @dev: PCI device
*
* The function is called before releasing the indicated PCI device.
*/
void pcibios_release_device(struct pci_dev *dev)
{
struct pci_controller *phb = pci_bus_to_host(dev->bus);
struct pci_dn *pdn = pci_get_pdn(dev);
if (phb->controller_ops.release_device)
phb->controller_ops.release_device(dev);
/* free()ing the pci_dn has been deferred to us, do it now */
if (pdn && (pdn->flags & PCI_DN_FLAG_DEAD)) {
pci_dbg(dev, "freeing dead pdn\n");
kfree(pdn);
}
}
/**
* pci_hp_remove_devices - remove all devices under this bus
* @bus: the indicated PCI bus
*
* Remove all of the PCI devices under this bus both from the
* linux pci device tree, and from the powerpc EEH address cache.
*/
void pci_hp_remove_devices(struct pci_bus *bus)
{
struct pci_dev *dev, *tmp;
struct pci_bus *child_bus;
/* First go down child busses */
list_for_each_entry(child_bus, &bus->children, node)
pci_hp_remove_devices(child_bus);
pr_debug("PCI: Removing devices on bus %04x:%02x\n",
pci_domain_nr(bus), bus->number);
list_for_each_entry_safe_reverse(dev, tmp, &bus->devices, bus_list) {
pr_debug(" Removing %s...\n", pci_name(dev));
pci_stop_and_remove_bus_device(dev);
}
}
EXPORT_SYMBOL_GPL(pci_hp_remove_devices);
/**
* pci_hp_add_devices - adds new pci devices to bus
* @bus: the indicated PCI bus
*
* This routine will find and fixup new pci devices under
* the indicated bus. This routine presumes that there
* might already be some devices under this bridge, so
* it carefully tries to add only new devices. (And that
* is how this routine differs from other, similar pcibios
* routines.)
*/
void pci_hp_add_devices(struct pci_bus *bus)
{
int slotno, mode, max;
struct pci_dev *dev;
struct pci_controller *phb;
struct device_node *dn = pci_bus_to_OF_node(bus);
phb = pci_bus_to_host(bus);
mode = PCI_PROBE_NORMAL;
if (phb->controller_ops.probe_mode)
mode = phb->controller_ops.probe_mode(bus);
if (mode == PCI_PROBE_DEVTREE) {
/* use ofdt-based probe */
of_rescan_bus(dn, bus);
} else if (mode == PCI_PROBE_NORMAL &&
dn->child && PCI_DN(dn->child)) {
/*
* Use legacy probe. In the partial hotplug case, we
* probably have grandchildren devices unplugged. So
* we don't check the return value from pci_scan_slot() in
* order for fully rescan all the way down to pick them up.
* They can have been removed during partial hotplug.
*/
slotno = PCI_SLOT(PCI_DN(dn->child)->devfn);
pci_scan_slot(bus, PCI_DEVFN(slotno, 0));
max = bus->busn_res.start;
/*
* Scan bridges that are already configured. We don't touch
* them unless they are misconfigured (which will be done in
* the second scan below).
*/
for_each_pci_bridge(dev, bus)
max = pci_scan_bridge(bus, dev, max, 0);
/* Scan bridges that need to be reconfigured */
for_each_pci_bridge(dev, bus)
max = pci_scan_bridge(bus, dev, max, 1);
}
pcibios_finish_adding_to_bus(bus);
}
EXPORT_SYMBOL_GPL(pci_hp_add_devices);