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linux-stable/drivers/pci/hotplug/sgi_hotplug.c
Lukas Wunner 51bbf9bee3 PCI: hotplug: Demidlayer registration with the core 
When a hotplug driver calls pci_hp_register(), all steps necessary for
registration are carried out in one go, including creation of a kobject
and addition to sysfs.  That's a problem for pciehp once it's converted
to enable/disable the slot exclusively from the IRQ thread:  The thread
needs to be spawned after creation of the kobject (because it uses the
kobject's name), but before addition to sysfs (because it will handle
enable/disable requests submitted via sysfs).

pci_hp_deregister() does offer a ->release callback that's invoked
after deletion from sysfs and before destruction of the kobject.  But
because pci_hp_register() doesn't offer a counterpart, hotplug drivers'
->probe and ->remove code becomes asymmetric, which is error prone
as recently discovered use-after-free bugs in pciehp's ->remove hook
have shown.

In a sense, this appears to be a case of the midlayer antipattern:

   "The core thesis of the "midlayer mistake" is that midlayers are
    bad and should not exist.  That common functionality which it is
    so tempting to put in a midlayer should instead be provided as
    library routines which can [be] used, augmented, or ignored by
    each bottom level driver independently.  Thus every subsystem
    that supports multiple implementations (or drivers) should
    provide a very thin top layer which calls directly into the
    bottom layer drivers, and a rich library of support code that
    eases the implementation of those drivers.  This library is
    available to, but not forced upon, those drivers."
        --  Neil Brown (2009), https://lwn.net/Articles/336262/

The presence of midlayer traits in the PCI hotplug core might be ascribed
to its age:  When it was introduced in February 2002, the blessings of a
library approach might not have been well known:
https://git.kernel.org/tglx/history/c/a8a2069f432c

For comparison, the driver core does offer split functions for creating
a kobject (device_initialize()) and addition to sysfs (device_add()) as
an alternative to carrying out everything at once (device_register()).
This was introduced in October 2002:
https://git.kernel.org/tglx/history/c/8b290eb19962

The odd ->release callback in the PCI hotplug core was added in 2003:
https://git.kernel.org/tglx/history/c/69f8d663b595

Clearly, a library approach would not force every hotplug driver to
implement a ->release callback, but rather allow the driver to remove
the sysfs files, release its data structures and finally destroy the
kobject.  Alternatively, a driver may choose to remove everything with
pci_hp_deregister(), then release its data structures.

To this end, offer drivers pci_hp_initialize() and pci_hp_add() as a
split-up version of pci_hp_register().  Likewise, offer pci_hp_del()
and pci_hp_destroy() as a split-up version of pci_hp_deregister().

Eliminate the ->release callback and move its code into each driver's
teardown routine.

Declare pci_hp_deregister() void, in keeping with the usual kernel
pattern that enablement can fail, but disablement cannot.  It only
returned an error if the caller passed in a NULL pointer or a slot which
has never or is no longer registered or is sharing its name with another
slot.  Those would be bugs, so WARN about them.  Few hotplug drivers
actually checked the return value and those that did only printed a
useless error message to dmesg.  Remove that.

For most drivers the conversion was straightforward since it doesn't
matter whether the code in the ->release callback is executed before or
after destruction of the kobject.  But in the case of ibmphp, it was
unclear to me whether setting slot_cur->ctrl and slot_cur->bus_on to
NULL needs to happen before the kobject is destroyed, so I erred on
the side of caution and ensured that the order stays the same.  Another
nontrivial case is pnv_php, I've found the list and kref logic difficult
to understand, however my impression was that it is safe to delete the
list element and drop the references until after the kobject is
destroyed.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>  # drivers/platform/x86
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Andy Shevchenko <andy@infradead.org>
2018-07-23 17:04:13 -05:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2005-2006 Silicon Graphics, Inc. All rights reserved.
*
* This work was based on the 2.4/2.6 kernel development by Dick Reigner.
* Work to add BIOS PROM support was completed by Mike Habeck.
*/
#include <linux/acpi.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <asm/sn/addrs.h>
#include <asm/sn/geo.h>
#include <asm/sn/l1.h>
#include <asm/sn/module.h>
#include <asm/sn/pcibr_provider.h>
#include <asm/sn/pcibus_provider_defs.h>
#include <asm/sn/pcidev.h>
#include <asm/sn/sn_feature_sets.h>
#include <asm/sn/sn_sal.h>
#include <asm/sn/types.h>
#include <asm/sn/acpi.h>
#include "../pci.h"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("SGI (prarit@sgi.com, dickie@sgi.com, habeck@sgi.com)");
MODULE_DESCRIPTION("SGI Altix Hot Plug PCI Controller Driver");
/* SAL call error codes. Keep in sync with prom header io/include/pcibr.h */
#define PCI_SLOT_ALREADY_UP 2 /* slot already up */
#define PCI_SLOT_ALREADY_DOWN 3 /* slot already down */
#define PCI_L1_ERR 7 /* L1 console command error */
#define PCI_EMPTY_33MHZ 15 /* empty 33 MHz bus */
#define PCIIO_ASIC_TYPE_TIOCA 4
#define PCI_L1_QSIZE 128 /* our L1 message buffer size */
#define SN_MAX_HP_SLOTS 32 /* max hotplug slots */
#define SN_SLOT_NAME_SIZE 33 /* size of name string */
/* internal list head */
static struct list_head sn_hp_list;
/* hotplug_slot struct's private pointer */
struct slot {
int device_num;
struct pci_bus *pci_bus;
/* this struct for glue internal only */
struct hotplug_slot *hotplug_slot;
struct list_head hp_list;
char physical_path[SN_SLOT_NAME_SIZE];
};
struct pcibr_slot_enable_resp {
int resp_sub_errno;
char resp_l1_msg[PCI_L1_QSIZE + 1];
};
struct pcibr_slot_disable_resp {
int resp_sub_errno;
char resp_l1_msg[PCI_L1_QSIZE + 1];
};
enum sn_pci_req_e {
PCI_REQ_SLOT_ELIGIBLE,
PCI_REQ_SLOT_DISABLE
};
static int enable_slot(struct hotplug_slot *slot);
static int disable_slot(struct hotplug_slot *slot);
static inline int get_power_status(struct hotplug_slot *slot, u8 *value);
static struct hotplug_slot_ops sn_hotplug_slot_ops = {
.enable_slot = enable_slot,
.disable_slot = disable_slot,
.get_power_status = get_power_status,
};
static DEFINE_MUTEX(sn_hotplug_mutex);
static ssize_t path_show(struct pci_slot *pci_slot, char *buf)
{
int retval = -ENOENT;
struct slot *slot = pci_slot->hotplug->private;
if (!slot)
return retval;
retval = sprintf(buf, "%s\n", slot->physical_path);
return retval;
}
static struct pci_slot_attribute sn_slot_path_attr = __ATTR_RO(path);
static int sn_pci_slot_valid(struct pci_bus *pci_bus, int device)
{
struct pcibus_info *pcibus_info;
u16 busnum, segment, ioboard_type;
pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);
/* Check to see if this is a valid slot on 'pci_bus' */
if (!(pcibus_info->pbi_valid_devices & (1 << device)))
return -EPERM;
ioboard_type = sn_ioboard_to_pci_bus(pci_bus);
busnum = pcibus_info->pbi_buscommon.bs_persist_busnum;
segment = pci_domain_nr(pci_bus) & 0xf;
/* Do not allow hotplug operations on base I/O cards */
if ((ioboard_type == L1_BRICKTYPE_IX ||
ioboard_type == L1_BRICKTYPE_IA) &&
(segment == 1 && busnum == 0 && device != 1))
return -EPERM;
return 1;
}
static int sn_pci_bus_valid(struct pci_bus *pci_bus)
{
struct pcibus_info *pcibus_info;
u32 asic_type;
u16 ioboard_type;
/* Don't register slots hanging off the TIOCA bus */
pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);
asic_type = pcibus_info->pbi_buscommon.bs_asic_type;
if (asic_type == PCIIO_ASIC_TYPE_TIOCA)
return -EPERM;
/* Only register slots in I/O Bricks that support hotplug */
ioboard_type = sn_ioboard_to_pci_bus(pci_bus);
switch (ioboard_type) {
case L1_BRICKTYPE_IX:
case L1_BRICKTYPE_PX:
case L1_BRICKTYPE_IA:
case L1_BRICKTYPE_PA:
case L1_BOARDTYPE_PCIX3SLOT:
return 1;
break;
default:
return -EPERM;
break;
}
return -EIO;
}
static int sn_hp_slot_private_alloc(struct hotplug_slot *bss_hotplug_slot,
struct pci_bus *pci_bus, int device,
char *name)
{
struct pcibus_info *pcibus_info;
struct slot *slot;
pcibus_info = SN_PCIBUS_BUSSOFT_INFO(pci_bus);
slot = kzalloc(sizeof(*slot), GFP_KERNEL);
if (!slot)
return -ENOMEM;
bss_hotplug_slot->private = slot;
slot->device_num = device;
slot->pci_bus = pci_bus;
sprintf(name, "%04x:%02x:%02x",
pci_domain_nr(pci_bus),
((u16)pcibus_info->pbi_buscommon.bs_persist_busnum),
device + 1);
sn_generate_path(pci_bus, slot->physical_path);
slot->hotplug_slot = bss_hotplug_slot;
list_add(&slot->hp_list, &sn_hp_list);
return 0;
}
static struct hotplug_slot *sn_hp_destroy(void)
{
struct slot *slot;
struct pci_slot *pci_slot;
struct hotplug_slot *bss_hotplug_slot = NULL;
list_for_each_entry(slot, &sn_hp_list, hp_list) {
bss_hotplug_slot = slot->hotplug_slot;
pci_slot = bss_hotplug_slot->pci_slot;
list_del(&((struct slot *)bss_hotplug_slot->private)->
hp_list);
sysfs_remove_file(&pci_slot->kobj,
&sn_slot_path_attr.attr);
break;
}
return bss_hotplug_slot;
}
static void sn_bus_free_data(struct pci_dev *dev)
{
struct pci_bus *subordinate_bus;
struct pci_dev *child;
/* Recursively clean up sn_irq_info structs */
if (dev->subordinate) {
subordinate_bus = dev->subordinate;
list_for_each_entry(child, &subordinate_bus->devices, bus_list)
sn_bus_free_data(child);
}
/*
* Some drivers may use dma accesses during the
* driver remove function. We release the sysdata
* areas after the driver remove functions have
* been called.
*/
sn_bus_store_sysdata(dev);
sn_pci_unfixup_slot(dev);
}
static int sn_slot_enable(struct hotplug_slot *bss_hotplug_slot,
int device_num, char **ssdt)
{
struct slot *slot = bss_hotplug_slot->private;
struct pcibus_info *pcibus_info;
struct pcibr_slot_enable_resp resp;
int rc;
pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
/*
* Power-on and initialize the slot in the SN
* PCI infrastructure.
*/
rc = sal_pcibr_slot_enable(pcibus_info, device_num, &resp, ssdt);
if (rc == PCI_SLOT_ALREADY_UP) {
pci_dbg(slot->pci_bus->self, "is already active\n");
return 1; /* return 1 to user */
}
if (rc == PCI_L1_ERR) {
pci_dbg(slot->pci_bus->self, "L1 failure %d with message: %s",
resp.resp_sub_errno, resp.resp_l1_msg);
return -EPERM;
}
if (rc) {
pci_dbg(slot->pci_bus->self, "insert failed with error %d sub-error %d\n",
rc, resp.resp_sub_errno);
return -EIO;
}
pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
pcibus_info->pbi_enabled_devices |= (1 << device_num);
return 0;
}
static int sn_slot_disable(struct hotplug_slot *bss_hotplug_slot,
int device_num, int action)
{
struct slot *slot = bss_hotplug_slot->private;
struct pcibus_info *pcibus_info;
struct pcibr_slot_disable_resp resp;
int rc;
pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
rc = sal_pcibr_slot_disable(pcibus_info, device_num, action, &resp);
if ((action == PCI_REQ_SLOT_ELIGIBLE) &&
(rc == PCI_SLOT_ALREADY_DOWN)) {
pci_dbg(slot->pci_bus->self, "Slot %s already inactive\n", slot->physical_path);
return 1; /* return 1 to user */
}
if ((action == PCI_REQ_SLOT_ELIGIBLE) && (rc == PCI_EMPTY_33MHZ)) {
pci_dbg(slot->pci_bus->self, "Cannot remove last 33MHz card\n");
return -EPERM;
}
if ((action == PCI_REQ_SLOT_ELIGIBLE) && (rc == PCI_L1_ERR)) {
pci_dbg(slot->pci_bus->self, "L1 failure %d with message \n%s\n",
resp.resp_sub_errno, resp.resp_l1_msg);
return -EPERM;
}
if ((action == PCI_REQ_SLOT_ELIGIBLE) && rc) {
pci_dbg(slot->pci_bus->self, "remove failed with error %d sub-error %d\n",
rc, resp.resp_sub_errno);
return -EIO;
}
if ((action == PCI_REQ_SLOT_ELIGIBLE) && !rc)
return 0;
if ((action == PCI_REQ_SLOT_DISABLE) && !rc) {
pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
pcibus_info->pbi_enabled_devices &= ~(1 << device_num);
pci_dbg(slot->pci_bus->self, "remove successful\n");
return 0;
}
if ((action == PCI_REQ_SLOT_DISABLE) && rc) {
pci_dbg(slot->pci_bus->self, "remove failed rc = %d\n", rc);
}
return rc;
}
/*
* Power up and configure the slot via a SAL call to PROM.
* Scan slot (and any children), do any platform specific fixup,
* and find device driver.
*/
static int enable_slot(struct hotplug_slot *bss_hotplug_slot)
{
struct slot *slot = bss_hotplug_slot->private;
struct pci_bus *new_bus = NULL;
struct pci_dev *dev;
int num_funcs;
int new_ppb = 0;
int rc;
char *ssdt = NULL;
void pcibios_fixup_device_resources(struct pci_dev *);
/* Serialize the Linux PCI infrastructure */
mutex_lock(&sn_hotplug_mutex);
/*
* Power-on and initialize the slot in the SN
* PCI infrastructure. Also, retrieve the ACPI SSDT
* table for the slot (if ACPI capable PROM).
*/
rc = sn_slot_enable(bss_hotplug_slot, slot->device_num, &ssdt);
if (rc) {
mutex_unlock(&sn_hotplug_mutex);
return rc;
}
if (ssdt)
ssdt = __va(ssdt);
/* Add the new SSDT for the slot to the ACPI namespace */
if (SN_ACPI_BASE_SUPPORT() && ssdt) {
acpi_status ret;
ret = acpi_load_table((struct acpi_table_header *)ssdt);
if (ACPI_FAILURE(ret)) {
printk(KERN_ERR "%s: acpi_load_table failed (0x%x)\n",
__func__, ret);
/* try to continue on */
}
}
num_funcs = pci_scan_slot(slot->pci_bus,
PCI_DEVFN(slot->device_num + 1, 0));
if (!num_funcs) {
pci_dbg(slot->pci_bus->self, "no device in slot\n");
mutex_unlock(&sn_hotplug_mutex);
return -ENODEV;
}
/*
* Map SN resources for all functions on the card
* to the Linux PCI interface and tell the drivers
* about them.
*/
list_for_each_entry(dev, &slot->pci_bus->devices, bus_list) {
if (PCI_SLOT(dev->devfn) != slot->device_num + 1)
continue;
/* Need to do slot fixup on PPB before fixup of children
* (PPB's pcidev_info needs to be in pcidev_info list
* before child's SN_PCIDEV_INFO() call to setup
* pdi_host_pcidev_info).
*/
pcibios_fixup_device_resources(dev);
if (SN_ACPI_BASE_SUPPORT())
sn_acpi_slot_fixup(dev);
else
sn_io_slot_fixup(dev);
if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
pci_hp_add_bridge(dev);
if (dev->subordinate) {
new_bus = dev->subordinate;
new_ppb = 1;
}
}
}
/*
* Add the slot's devices to the ACPI infrastructure */
if (SN_ACPI_BASE_SUPPORT() && ssdt) {
unsigned long long adr;
struct acpi_device *pdevice;
acpi_handle phandle;
acpi_handle chandle = NULL;
acpi_handle rethandle;
acpi_status ret;
phandle = acpi_device_handle(PCI_CONTROLLER(slot->pci_bus)->companion);
if (acpi_bus_get_device(phandle, &pdevice)) {
pci_dbg(slot->pci_bus->self, "no parent device, assuming NULL\n");
pdevice = NULL;
}
acpi_scan_lock_acquire();
/*
* Walk the rootbus node's immediate children looking for
* the slot's device node(s). There can be more than
* one for multifunction devices.
*/
for (;;) {
rethandle = NULL;
ret = acpi_get_next_object(ACPI_TYPE_DEVICE,
phandle, chandle,
&rethandle);
if (ret == AE_NOT_FOUND || rethandle == NULL)
break;
chandle = rethandle;
ret = acpi_evaluate_integer(chandle, METHOD_NAME__ADR,
NULL, &adr);
if (ACPI_SUCCESS(ret) &&
(adr>>16) == (slot->device_num + 1)) {
ret = acpi_bus_scan(chandle);
if (ACPI_FAILURE(ret)) {
printk(KERN_ERR "%s: acpi_bus_scan failed (0x%x) for slot %d func %d\n",
__func__, ret, (int)(adr>>16),
(int)(adr&0xffff));
/* try to continue on */
}
}
}
acpi_scan_lock_release();
}
pci_lock_rescan_remove();
/* Call the driver for the new device */
pci_bus_add_devices(slot->pci_bus);
/* Call the drivers for the new devices subordinate to PPB */
if (new_ppb)
pci_bus_add_devices(new_bus);
pci_unlock_rescan_remove();
mutex_unlock(&sn_hotplug_mutex);
if (rc == 0)
pci_dbg(slot->pci_bus->self, "insert operation successful\n");
else
pci_dbg(slot->pci_bus->self, "insert operation failed rc = %d\n", rc);
return rc;
}
static int disable_slot(struct hotplug_slot *bss_hotplug_slot)
{
struct slot *slot = bss_hotplug_slot->private;
struct pci_dev *dev, *temp;
int rc;
acpi_handle ssdt_hdl = NULL;
/* Acquire update access to the bus */
mutex_lock(&sn_hotplug_mutex);
/* is it okay to bring this slot down? */
rc = sn_slot_disable(bss_hotplug_slot, slot->device_num,
PCI_REQ_SLOT_ELIGIBLE);
if (rc)
goto leaving;
/* free the ACPI resources for the slot */
if (SN_ACPI_BASE_SUPPORT() &&
PCI_CONTROLLER(slot->pci_bus)->companion) {
unsigned long long adr;
struct acpi_device *device;
acpi_handle phandle;
acpi_handle chandle = NULL;
acpi_handle rethandle;
acpi_status ret;
/* Get the rootbus node pointer */
phandle = acpi_device_handle(PCI_CONTROLLER(slot->pci_bus)->companion);
acpi_scan_lock_acquire();
/*
* Walk the rootbus node's immediate children looking for
* the slot's device node(s). There can be more than
* one for multifunction devices.
*/
for (;;) {
rethandle = NULL;
ret = acpi_get_next_object(ACPI_TYPE_DEVICE,
phandle, chandle,
&rethandle);
if (ret == AE_NOT_FOUND || rethandle == NULL)
break;
chandle = rethandle;
ret = acpi_evaluate_integer(chandle,
METHOD_NAME__ADR,
NULL, &adr);
if (ACPI_SUCCESS(ret) &&
(adr>>16) == (slot->device_num + 1)) {
/* retain the owner id */
ssdt_hdl = chandle;
ret = acpi_bus_get_device(chandle,
&device);
if (ACPI_SUCCESS(ret))
acpi_bus_trim(device);
}
}
acpi_scan_lock_release();
}
pci_lock_rescan_remove();
/* Free the SN resources assigned to the Linux device.*/
list_for_each_entry_safe(dev, temp, &slot->pci_bus->devices, bus_list) {
if (PCI_SLOT(dev->devfn) != slot->device_num + 1)
continue;
pci_dev_get(dev);
sn_bus_free_data(dev);
pci_stop_and_remove_bus_device(dev);
pci_dev_put(dev);
}
pci_unlock_rescan_remove();
/* Remove the SSDT for the slot from the ACPI namespace */
if (SN_ACPI_BASE_SUPPORT() && ssdt_hdl) {
acpi_status ret;
ret = acpi_unload_parent_table(ssdt_hdl);
if (ACPI_FAILURE(ret)) {
acpi_handle_err(ssdt_hdl,
"%s: acpi_unload_parent_table failed (0x%x)\n",
__func__, ret);
/* try to continue on */
}
}
/* free the collected sysdata pointers */
sn_bus_free_sysdata();
/* Deactivate slot */
rc = sn_slot_disable(bss_hotplug_slot, slot->device_num,
PCI_REQ_SLOT_DISABLE);
leaving:
/* Release the bus lock */
mutex_unlock(&sn_hotplug_mutex);
return rc;
}
static inline int get_power_status(struct hotplug_slot *bss_hotplug_slot,
u8 *value)
{
struct slot *slot = bss_hotplug_slot->private;
struct pcibus_info *pcibus_info;
u32 power;
pcibus_info = SN_PCIBUS_BUSSOFT_INFO(slot->pci_bus);
mutex_lock(&sn_hotplug_mutex);
power = pcibus_info->pbi_enabled_devices & (1 << slot->device_num);
*value = power ? 1 : 0;
mutex_unlock(&sn_hotplug_mutex);
return 0;
}
static void sn_release_slot(struct hotplug_slot *bss_hotplug_slot)
{
kfree(bss_hotplug_slot->info);
kfree(bss_hotplug_slot->private);
kfree(bss_hotplug_slot);
}
static int sn_hotplug_slot_register(struct pci_bus *pci_bus)
{
int device;
struct pci_slot *pci_slot;
struct hotplug_slot *bss_hotplug_slot;
char name[SN_SLOT_NAME_SIZE];
int rc = 0;
/*
* Currently only four devices are supported,
* in the future there maybe more -- up to 32.
*/
for (device = 0; device < SN_MAX_HP_SLOTS ; device++) {
if (sn_pci_slot_valid(pci_bus, device) != 1)
continue;
bss_hotplug_slot = kzalloc(sizeof(*bss_hotplug_slot),
GFP_KERNEL);
if (!bss_hotplug_slot) {
rc = -ENOMEM;
goto alloc_err;
}
bss_hotplug_slot->info =
kzalloc(sizeof(struct hotplug_slot_info),
GFP_KERNEL);
if (!bss_hotplug_slot->info) {
rc = -ENOMEM;
goto alloc_err;
}
if (sn_hp_slot_private_alloc(bss_hotplug_slot,
pci_bus, device, name)) {
rc = -ENOMEM;
goto alloc_err;
}
bss_hotplug_slot->ops = &sn_hotplug_slot_ops;
rc = pci_hp_register(bss_hotplug_slot, pci_bus, device, name);
if (rc)
goto register_err;
pci_slot = bss_hotplug_slot->pci_slot;
rc = sysfs_create_file(&pci_slot->kobj,
&sn_slot_path_attr.attr);
if (rc)
goto register_err;
}
pci_dbg(pci_bus->self, "Registered bus with hotplug\n");
return rc;
register_err:
pci_dbg(pci_bus->self, "bus failed to register with err = %d\n",
rc);
alloc_err:
if (rc == -ENOMEM)
pci_dbg(pci_bus->self, "Memory allocation error\n");
/* destroy THIS element */
if (bss_hotplug_slot)
sn_release_slot(bss_hotplug_slot);
/* destroy anything else on the list */
while ((bss_hotplug_slot = sn_hp_destroy())) {
pci_hp_deregister(bss_hotplug_slot);
sn_release_slot(bss_hotplug_slot);
}
return rc;
}
static int __init sn_pci_hotplug_init(void)
{
struct pci_bus *pci_bus = NULL;
int rc;
int registered = 0;
if (!sn_prom_feature_available(PRF_HOTPLUG_SUPPORT)) {
printk(KERN_ERR "%s: PROM version does not support hotplug.\n",
__func__);
return -EPERM;
}
INIT_LIST_HEAD(&sn_hp_list);
while ((pci_bus = pci_find_next_bus(pci_bus))) {
if (!pci_bus->sysdata)
continue;
rc = sn_pci_bus_valid(pci_bus);
if (rc != 1) {
pci_dbg(pci_bus->self, "not a valid hotplug bus\n");
continue;
}
pci_dbg(pci_bus->self, "valid hotplug bus\n");
rc = sn_hotplug_slot_register(pci_bus);
if (!rc) {
registered = 1;
} else {
registered = 0;
break;
}
}
return registered == 1 ? 0 : -ENODEV;
}
static void __exit sn_pci_hotplug_exit(void)
{
struct hotplug_slot *bss_hotplug_slot;
while ((bss_hotplug_slot = sn_hp_destroy())) {
pci_hp_deregister(bss_hotplug_slot);
sn_release_slot(bss_hotplug_slot);
}
if (!list_empty(&sn_hp_list))
printk(KERN_ERR "%s: internal list is not empty\n", __FILE__);
}
module_init(sn_pci_hotplug_init);
module_exit(sn_pci_hotplug_exit);
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