On Saturday, January 19, 2013 12:07:43 AM Jiang Liu wrote:
> Currently the pci_slot driver doesn't update PCI slot information
> when PCI device hotplug event happens, which may cause memory leak
> and returning stale information to user.
>
> By hooking PCI bus notifications, this patch unifies the way to
> create/destroy PCI slots when:
> 1) create PCI hierarchy at boot time
> 2) create PCI hierarchy for PCI root bridge hot-adding
> 3) create PCI hierarchy for PCI device hotplug hot-adding
> 4) destroy PCI hierarchy for PCI root bridge hot-removal
> 4) destroy PCI hierarchy for PCI device hot-removal
This patch also removes some code which apparently is not necessary any more.
It would be good to write in the changelog _why_ that code isn't necessary.
Apart from this, looks good.
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
> ---
> drivers/acpi/pci_slot.c | 197 +++++++++++++----------------------------------
> 1 file changed, 54 insertions(+), 143 deletions(-)
>
> diff --git a/drivers/acpi/pci_slot.c b/drivers/acpi/pci_slot.c
> index a7d7e77..2b38f4d 100644
> --- a/drivers/acpi/pci_slot.c
> +++ b/drivers/acpi/pci_slot.c
> @@ -9,6 +9,9 @@
> * Copyright (C) 2007-2008 Hewlett-Packard Development Company, L.P.
> * Alex Chiang <achiang@xxxxxx>
> *
> + * Copyright (C) 2013 Huawei Tech. Co., Ltd.
> + * Jiang Liu <jiang.liu@xxxxxxxxxx>
> + *
> * This program is free software; you can redistribute it and/or modify it
> * under the terms and conditions of the GNU General Public License,
> * version 2, as published by the Free Software Foundation.
> @@ -28,10 +31,9 @@
> #include <linux/init.h>
> #include <linux/slab.h>
> #include <linux/types.h>
> +#include <linux/list.h>
> #include <linux/pci.h>
> #include <linux/acpi.h>
> -#include <acpi/acpi_bus.h>
> -#include <acpi/acpi_drivers.h>
> #include <linux/dmi.h>
>
> static bool debug;
> @@ -62,20 +64,12 @@ ACPI_MODULE_NAME("pci_slot");
> #define SLOT_NAME_SIZE 21 /* Inspired by #define in acpiphp.h */
>
> struct acpi_pci_slot {
> - acpi_handle root_handle; /* handle of the root bridge */
> struct pci_slot *pci_slot; /* corresponding pci_slot */
> struct list_head list; /* node in the list of slots */
> };
>
> -static int acpi_pci_slot_add(struct acpi_pci_root *root);
> -static void acpi_pci_slot_remove(struct acpi_pci_root *root);
> -
> static LIST_HEAD(slot_list);
> static DEFINE_MUTEX(slot_list_lock);
> -static struct acpi_pci_driver acpi_pci_slot_driver = {
> - .add = acpi_pci_slot_add,
> - .remove = acpi_pci_slot_remove,
> -};
>
> static int
> check_slot(acpi_handle handle, unsigned long long *sun)
> @@ -114,21 +108,8 @@ out:
> return device;
> }
>
> -struct callback_args {
> - acpi_walk_callback user_function; /* only for walk_p2p_bridge */
> - struct pci_bus *pci_bus;
> - acpi_handle root_handle;
> -};
> -
> /*
> - * register_slot
> - *
> - * Called once for each SxFy object in the namespace. Don't worry about
> - * calling pci_create_slot multiple times for the same pci_bus:device,
> - * since each subsequent call simply bumps the refcount on the pci_slot.
> - *
> - * The number of calls to pci_destroy_slot from unregister_slot is
> - * symmetrical.
> + * Check whether handle has an associated slot and create PCI slot if it has.
> */
> static acpi_status
> register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
> @@ -138,13 +119,23 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
> char name[SLOT_NAME_SIZE];
> struct acpi_pci_slot *slot;
> struct pci_slot *pci_slot;
> - struct callback_args *parent_context = context;
> - struct pci_bus *pci_bus = parent_context->pci_bus;
> + struct pci_bus *pci_bus = context;
>
> device = check_slot(handle, &sun);
> if (device < 0)
> return AE_OK;
>
> + /*
> + * There may be multiple PCI functions associated with the same slot.
> + * Check whether PCI slot has already been created for this PCI device.
> + */
> + list_for_each_entry(slot, &slot_list, list) {
> + pci_slot = slot->pci_slot;
> + if (pci_slot->bus == pci_bus && pci_slot->number == device) {
> + return AE_OK;
> + }
> + }
> +
> slot = kmalloc(sizeof(*slot), GFP_KERNEL);
> if (!slot) {
> err("%s: cannot allocate memory\n", __func__);
> @@ -159,12 +150,9 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
> return AE_OK;
> }
>
> - slot->root_handle = parent_context->root_handle;
> slot->pci_slot = pci_slot;
> INIT_LIST_HEAD(&slot->list);
> - mutex_lock(&slot_list_lock);
> list_add(&slot->list, &slot_list);
> - mutex_unlock(&slot_list_lock);
>
> get_device(&pci_bus->dev);
>
> @@ -174,137 +162,60 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
> return AE_OK;
> }
>
> -/*
> - * walk_p2p_bridge - discover and walk p2p bridges
> - * @handle: points to an acpi_pci_root
> - * @context: p2p_bridge_context pointer
> - *
> - * Note that when we call ourselves recursively, we pass a different
> - * value of pci_bus in the child_context.
> - */
> -static acpi_status
> -walk_p2p_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
> -{
> - int device, function;
> - unsigned long long adr;
> - acpi_status status;
> - acpi_handle dummy_handle;
> - acpi_walk_callback user_function;
> -
> - struct pci_dev *dev;
> - struct pci_bus *pci_bus;
> - struct callback_args child_context;
> - struct callback_args *parent_context = context;
> -
> - pci_bus = parent_context->pci_bus;
> - user_function = parent_context->user_function;
> -
> - status = acpi_get_handle(handle, "_ADR", &dummy_handle);
> - if (ACPI_FAILURE(status))
> - return AE_OK;
> -
> - status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
> - if (ACPI_FAILURE(status))
> - return AE_OK;
> -
> - device = (adr >> 16) & 0xffff;
> - function = adr & 0xffff;
> -
> - dev = pci_get_slot(pci_bus, PCI_DEVFN(device, function));
> - if (!dev || !dev->subordinate)
> - goto out;
> -
> - child_context.pci_bus = dev->subordinate;
> - child_context.user_function = user_function;
> - child_context.root_handle = parent_context->root_handle;
> -
> - dbg("p2p bridge walk, pci_bus = %x\n", dev->subordinate->number);
> - status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
> - user_function, NULL, &child_context, NULL);
> - if (ACPI_FAILURE(status))
> - goto out;
> -
> - status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
> - walk_p2p_bridge, NULL, &child_context, NULL);
> -out:
> - pci_dev_put(dev);
> - return AE_OK;
> -}
> -
> -/*
> - * walk_root_bridge - generic root bridge walker
> - * @root: poiner of an acpi_pci_root
> - * @user_function: user callback for slot objects
> - *
> - * Call user_function for all objects underneath this root bridge.
> - * Walk p2p bridges underneath us and call user_function on those too.
> - */
> -static int
> -walk_root_bridge(struct acpi_pci_root *root, acpi_walk_callback user_function)
> +static void acpi_pci_slot_notify_add(struct pci_bus *bus)
> {
> - acpi_status status;
> - acpi_handle handle = root->device->handle;
> - struct pci_bus *pci_bus = root->bus;
> - struct callback_args context;
> -
> - context.pci_bus = pci_bus;
> - context.user_function = user_function;
> - context.root_handle = handle;
> -
> - dbg("root bridge walk, pci_bus = %x\n", pci_bus->number);
> - status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
> - user_function, NULL, &context, NULL);
> - if (ACPI_FAILURE(status))
> - return status;
> -
> - status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
> - walk_p2p_bridge, NULL, &context, NULL);
> - if (ACPI_FAILURE(status))
> - err("%s: walk_p2p_bridge failure - %d\n", __func__, status);
> -
> - return status;
> -}
> + acpi_handle handle = NULL;
>
> -/*
> - * acpi_pci_slot_add
> - * @handle: points to an acpi_pci_root
> - */
> -static int
> -acpi_pci_slot_add(struct acpi_pci_root *root)
> -{
> - acpi_status status;
> -
> - status = walk_root_bridge(root, register_slot);
> - if (ACPI_FAILURE(status))
> - err("%s: register_slot failure - %d\n", __func__, status);
> + if (bus->bridge)
> + handle = DEVICE_ACPI_HANDLE(bus->bridge);
> + if (!handle)
> + return;
>
> - return status;
> + mutex_lock(&slot_list_lock);
> + acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
> + register_slot, NULL, bus, NULL);
> + mutex_unlock(&slot_list_lock);
> }
>
> -/*
> - * acpi_pci_slot_remove
> - * @handle: points to an acpi_pci_root
> - */
> -static void
> -acpi_pci_slot_remove(struct acpi_pci_root *root)
> +static void acpi_pci_slot_notify_del(struct pci_bus *bus)
> {
> struct acpi_pci_slot *slot, *tmp;
> - struct pci_bus *pbus;
> - acpi_handle handle = root->device->handle;
>
> mutex_lock(&slot_list_lock);
> list_for_each_entry_safe(slot, tmp, &slot_list, list) {
> - if (slot->root_handle == handle) {
> + if (slot->pci_slot->bus == bus) {
> list_del(&slot->list);
> - pbus = slot->pci_slot->bus;
> pci_destroy_slot(slot->pci_slot);
> - put_device(&pbus->dev);
> + put_device(&bus->dev);
> kfree(slot);
> }
> }
> mutex_unlock(&slot_list_lock);
> }
>
> +static int acpi_pci_slot_notify_fn(struct notifier_block *nb,
> + unsigned long event, void *data)
> +{
> + struct pci_bus *bus = data;
> +
> + switch (event) {
> + case PCI_NOTIFY_POST_BUS_ADD:
> + acpi_pci_slot_notify_add(bus);
> + break;
> + case PCI_NOTIFY_PRE_BUS_DEL:
> + acpi_pci_slot_notify_del(bus);
> + break;
> + default:
> + return NOTIFY_DONE;
> + }
> +
> + return NOTIFY_OK;
> +}
> +
> +static struct notifier_block acpi_pci_slot_notifier = {
> + .notifier_call = &acpi_pci_slot_notify_fn,
> +};
> +
> static int do_sta_before_sun(const struct dmi_system_id *d)
> {
> info("%s detected: will evaluate _STA before calling _SUN\n", d->ident);
> @@ -333,5 +244,5 @@ static struct dmi_system_id acpi_pci_slot_dmi_table[] __initdata = {
> void __init acpi_pci_slot_init(void)
> {
> dmi_check_system(acpi_pci_slot_dmi_table);
> - acpi_pci_register_driver(&acpi_pci_slot_driver);
> + pci_bus_register_notifier(&acpi_pci_slot_notifier);
> }
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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