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Date: Mon, 20 May 2013 23:52:52 +0800
From: Liu Jiang <liuj97@...il.com>
To: Gu Zheng <guz.fnst@...fujitsu.com>
CC: Bjorn Helgaas <bhelgaas@...gle.com>,
Yinghai Lu <yinghai@...nel.org>,
Jiang Liu <jiang.liu@...wei.com>,
"Rafael J . Wysocki" <rjw@...k.pl>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Toshi Kani <toshi.kani@...com>,
Myron Stowe <myron.stowe@...hat.com>,
Yijing Wang <wangyijing@...wei.com>, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2, part 1 8/9] PCI: make PCI host bridge/bus creating
and destroying logic symmetric
On Mon 20 May 2013 02:35:31 PM CST, Gu Zheng wrote:
>
> On 05/14/2013 12:08 AM, Jiang Liu wrote:
>
>> This patch makes PCI host bridge/bus creating and destroying logic
>> symmetric by using device_initialize()/device_add()/device_del()/put_device()
>> pairs as discussed in thread at:
>> http://comments.gmane.org/gmane.linux.kernel.pci/22073
>>
>> It also fixes a bug in error recovery path in pci_create_root_bus()
>> which may kfree() an in-use host bridge object.
>>
>> Signed-off-by: Jiang Liu <jiang.liu@...wei.com>
>> Cc: Yinghai Lu <yinghai@...nel.org>
>> ---
>> drivers/pci/probe.c | 84 +++++++++++++++++++++++-----------------------------
>> drivers/pci/remove.c | 3 +-
>> 2 files changed, 39 insertions(+), 48 deletions(-)
>>
>> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
>> index bc075a3..a2617c2 100644
>> --- a/drivers/pci/probe.c
>> +++ b/drivers/pci/probe.c
>> @@ -451,7 +451,7 @@ void pci_read_bridge_bases(struct pci_bus *child)
>> }
>> }
>>
>> -static struct pci_bus * pci_alloc_bus(void)
>> +static struct pci_bus *pci_alloc_bus(struct pci_ops *ops, void *sd, int bus)
>> {
>> struct pci_bus *b;
>>
>> @@ -464,10 +464,32 @@ static struct pci_bus * pci_alloc_bus(void)
>> INIT_LIST_HEAD(&b->resources);
>> b->max_bus_speed = PCI_SPEED_UNKNOWN;
>> b->cur_bus_speed = PCI_SPEED_UNKNOWN;
>> + b->sysdata = sd;
>> + b->ops = ops;
>> + b->number = bus;
>> + b->busn_res.start = bus;
>> + b->busn_res.end = 0xff;
>> + b->busn_res.flags = IORESOURCE_BUS;
>> + b->dev.class = &pcibus_class;
>> + dev_set_name(&b->dev, "%04x:%02x", pci_domain_nr(b), bus);
>> + device_initialize(&b->dev);
>> }
>> +
>> return b;
>> }
>>
>> +static void pci_release_host_bridge_dev(struct device *dev)
>> +{
>> + struct pci_host_bridge *bridge = to_pci_host_bridge(dev);
>> +
>> + if (bridge->release_fn)
>> + bridge->release_fn(bridge);
>> +
>> + pci_free_resource_list(&bridge->windows);
>> +
>> + kfree(bridge);
>> +}
>> +
>> static struct pci_host_bridge *pci_alloc_host_bridge(struct pci_bus *b)
>> {
>> struct pci_host_bridge *bridge;
>> @@ -476,6 +498,10 @@ static struct pci_host_bridge *pci_alloc_host_bridge(struct pci_bus *b)
>> if (bridge) {
>> INIT_LIST_HEAD(&bridge->windows);
>> bridge->bus = b;
>> + bridge->dev.release = pci_release_host_bridge_dev;
>> + dev_set_name(&bridge->dev, "pci%04x:%02x",
>> + pci_domain_nr(b), b->number);
>> + device_initialize(&bridge->dev);
>> }
>>
>> return bridge;
>> @@ -628,28 +654,13 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
>> /*
>> * Allocate a new bus, and inherit stuff from the parent..
>> */
>> - child = pci_alloc_bus();
>> + child = pci_alloc_bus(parent->ops, parent->sysdata, busnr);
>> if (!child)
>> return NULL;
>>
>> child->parent = parent;
>> - child->ops = parent->ops;
>> - child->sysdata = parent->sysdata;
>> child->bus_flags = parent->bus_flags;
>> -
>> - /* initialize some portions of the bus device, but don't register it
>> - * now as the parent is not properly set up yet.
>> - */
>> - child->dev.class = &pcibus_class;
>> - dev_set_name(&child->dev, "%04x:%02x", pci_domain_nr(child), busnr);
>> -
>> - /*
>> - * Set up the primary, secondary and subordinate
>> - * bus numbers.
>> - */
>> - child->number = child->busn_res.start = busnr;
>> child->primary = parent->busn_res.start;
>> - child->busn_res.end = 0xff;
>>
>> if (!bridge) {
>> child->dev.parent = parent->bridge;
>> @@ -670,7 +681,7 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
>> bridge->subordinate = child;
>>
>> add_dev:
>> - ret = device_register(&child->dev);
>> + ret = device_add(&child->dev);
>> WARN_ON(ret < 0);
>>
>> pcibios_add_bus(child);
>> @@ -1190,18 +1201,6 @@ int pci_cfg_space_size(struct pci_dev *dev)
>> return PCI_CFG_SPACE_SIZE;
>> }
>>
>> -static void pci_release_bus_bridge_dev(struct device *dev)
>> -{
>> - struct pci_host_bridge *bridge = to_pci_host_bridge(dev);
>> -
>> - if (bridge->release_fn)
>> - bridge->release_fn(bridge);
>> -
>> - pci_free_resource_list(&bridge->windows);
>> -
>> - kfree(bridge);
>> -}
>> -
>> struct pci_dev *pci_alloc_dev(struct pci_bus *bus)
>> {
>> struct pci_dev *dev;
>> @@ -1688,13 +1687,10 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
>> char bus_addr[64];
>> char *fmt;
>>
>> - b = pci_alloc_bus();
>> + b = pci_alloc_bus(ops, sysdata, bus);
>> if (!b)
>> return NULL;
>>
>> - b->sysdata = sysdata;
>> - b->ops = ops;
>> - b->number = b->busn_res.start = bus;
>> b2 = pci_find_bus(pci_domain_nr(b), bus);
>> if (b2) {
>> /* If we already got to this bus through a different bridge, ignore it */
>> @@ -1706,27 +1702,22 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
>> if (!bridge)
>> goto err_out;
>>
>> - bridge->dev.parent = parent;
>> - bridge->dev.release = pci_release_bus_bridge_dev;
>> - dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus);
>> error = pcibios_root_bridge_prepare(bridge);
>> if (error)
>> goto bridge_dev_reg_err;
>>
>> - error = device_register(&bridge->dev);
>> + bridge->dev.parent = parent;
>> + error = device_add(&bridge->dev);
>> if (error)
>> goto bridge_dev_reg_err;
>> +
>> b->bridge = get_device(&bridge->dev);
>> device_enable_async_suspend(b->bridge);
>> pci_set_bus_of_node(b);
>> -
>> if (!parent)
>> set_dev_node(b->bridge, pcibus_to_node(b));
>> -
>> - b->dev.class = &pcibus_class;
>> b->dev.parent = b->bridge;
>> - dev_set_name(&b->dev, "%04x:%02x", pci_domain_nr(b), bus);
>> - error = device_register(&b->dev);
>> + error = device_add(&b->dev);
>> if (error)
>> goto class_dev_reg_err;
>>
>> @@ -1769,12 +1760,11 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
>> return b;
>>
>> class_dev_reg_err:
>> - put_device(&bridge->dev);
>> - device_unregister(&bridge->dev);
>> + device_del(&bridge->dev);
>> bridge_dev_reg_err:
>> - kfree(bridge);
>> + put_device(&bridge->dev);
>> err_out:
>> - kfree(b);
>> + put_device(&b->dev);
>> return NULL;
>> }
>
> Hi Jiang,
> I think the changes here may lead to memleak, doesn't it?
>
> Best regards,
> Gu
Hi Gu Zheng,
I have checked to code again and didn't find the memory leakage
issue.
Could you please help to give more hints about the leakage?
Thanks!
Gerry
>
>>
>> diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
>> index 8fc54b7..b0ce875 100644
>> --- a/drivers/pci/remove.c
>> +++ b/drivers/pci/remove.c
>> @@ -52,7 +52,8 @@ void pci_remove_bus(struct pci_bus *bus)
>> up_write(&pci_bus_sem);
>> pci_remove_legacy_files(bus);
>> pcibios_remove_bus(bus);
>> - device_unregister(&bus->dev);
>> + device_del(&bus->dev);
>> + put_device(&bus->dev);
>> }
>> EXPORT_SYMBOL(pci_remove_bus);
>>
>
>
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