linux/drivers/pci/hotplug/s390_pci_hpc.c
Niklas Schnelle 0b13525c20 s390/pci: fix leak of PCI device structure
In commit 05bc1be6db ("s390/pci: create zPCI bus") we removed the
pci_dev_put() call matching the earlier pci_get_slot() done as part of
__zpci_event_availability(). This was based on the wrong understanding
that the device_put() done as part of pci_destroy_device() would counter
the pci_get_slot() when it only counters the initial reference. This
same understanding and existing bad example also lead to not doing
a pci_dev_put() in zpci_remove_device().

Since releasing the PCI devices, unlike releasing the PCI slot, does not
print any debug message for testing I added one in pci_release_dev().
This revealed that we are indeed leaking the PCI device on PCI
hotunplug. Further testing also revealed another missing pci_dev_put() in
disable_slot().

Fix this by adding the missing pci_dev_put() in disable_slot() and fix
zpci_remove_device() with the correct pci_dev_put() calls. Also instead
of calling pci_get_slot() in __zpci_event_availability() to determine if
a PCI device is registered and then doing the same again in
zpci_remove_device() do this once in zpci_remove_device() which makes
sure that the pdev in __zpci_event_availability() is only used for the
result of pci_scan_single_device() which does not need a reference count
decremnt as its ownership goes to the PCI bus.

Also move the check if zdev->zbus->bus is set into zpci_remove_device()
since it may be that we're removing a device with devfn != 0 which never
had a PCI bus. So we can still set the pdev->error_state to indicate
that the device is not usable anymore, add a flag to set the error state.

Fixes: 05bc1be6db ("s390/pci: create zPCI bus")
Cc: <stable@vger.kernel.org> # 5.8+: e1bff843cd s390/pci: remove superfluous zdev->zbus check
Cc: <stable@vger.kernel.org> # 5.8+: ba764dd703 s390/pci: refactor zpci_create_device()
Cc: <stable@vger.kernel.org> # 5.8+
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-03-15 19:10:56 +01:00

153 lines
3.1 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* PCI Hot Plug Controller Driver for System z
*
* Copyright 2012 IBM Corp.
*
* Author(s):
* Jan Glauber <jang@linux.vnet.ibm.com>
*/
#define KMSG_COMPONENT "zpci"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <asm/pci_debug.h>
#include <asm/sclp.h>
#define SLOT_NAME_SIZE 10
static int zpci_fn_configured(enum zpci_state state)
{
return state == ZPCI_FN_STATE_CONFIGURED ||
state == ZPCI_FN_STATE_ONLINE;
}
static inline int zdev_configure(struct zpci_dev *zdev)
{
int ret = sclp_pci_configure(zdev->fid);
zpci_dbg(3, "conf fid:%x, rc:%d\n", zdev->fid, ret);
if (!ret)
zdev->state = ZPCI_FN_STATE_CONFIGURED;
return ret;
}
static inline int zdev_deconfigure(struct zpci_dev *zdev)
{
int ret = sclp_pci_deconfigure(zdev->fid);
zpci_dbg(3, "deconf fid:%x, rc:%d\n", zdev->fid, ret);
if (!ret)
zdev->state = ZPCI_FN_STATE_STANDBY;
return ret;
}
static int enable_slot(struct hotplug_slot *hotplug_slot)
{
struct zpci_dev *zdev = container_of(hotplug_slot, struct zpci_dev,
hotplug_slot);
struct zpci_bus *zbus = zdev->zbus;
int rc;
if (zdev->state != ZPCI_FN_STATE_STANDBY)
return -EIO;
rc = zdev_configure(zdev);
if (rc)
return rc;
rc = zpci_enable_device(zdev);
if (rc)
goto out_deconfigure;
pci_scan_slot(zbus->bus, zdev->devfn);
pci_lock_rescan_remove();
pci_bus_add_devices(zbus->bus);
pci_unlock_rescan_remove();
return rc;
out_deconfigure:
zdev_deconfigure(zdev);
return rc;
}
static int disable_slot(struct hotplug_slot *hotplug_slot)
{
struct zpci_dev *zdev = container_of(hotplug_slot, struct zpci_dev,
hotplug_slot);
struct pci_dev *pdev;
int rc;
if (!zpci_fn_configured(zdev->state))
return -EIO;
pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
if (pdev && pci_num_vf(pdev)) {
pci_dev_put(pdev);
return -EBUSY;
}
pci_dev_put(pdev);
zpci_remove_device(zdev, false);
rc = zpci_disable_device(zdev);
if (rc)
return rc;
return zdev_deconfigure(zdev);
}
static int get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct zpci_dev *zdev = container_of(hotplug_slot, struct zpci_dev,
hotplug_slot);
switch (zdev->state) {
case ZPCI_FN_STATE_STANDBY:
*value = 0;
break;
default:
*value = 1;
break;
}
return 0;
}
static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
/* if the slot exits it always contains a function */
*value = 1;
return 0;
}
static const struct hotplug_slot_ops s390_hotplug_slot_ops = {
.enable_slot = enable_slot,
.disable_slot = disable_slot,
.get_power_status = get_power_status,
.get_adapter_status = get_adapter_status,
};
int zpci_init_slot(struct zpci_dev *zdev)
{
char name[SLOT_NAME_SIZE];
struct zpci_bus *zbus = zdev->zbus;
zdev->hotplug_slot.ops = &s390_hotplug_slot_ops;
snprintf(name, SLOT_NAME_SIZE, "%08x", zdev->fid);
return pci_hp_register(&zdev->hotplug_slot, zbus->bus,
zdev->devfn, name);
}
void zpci_exit_slot(struct zpci_dev *zdev)
{
pci_hp_deregister(&zdev->hotplug_slot);
}