Re: [RFC PATCH v1 21/22] PCI: cleanups for PCI bus lock implementation

From: Jiang Liu <jiang.liu@huawei.com>
To: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jiang Liu <liuj97@gmail.com>, Don Dutile <ddutile@redhat.com>,
	Yinghai Lu <yinghai@kernel.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
	Taku Izumi <izumi.taku@jp.fujitsu.com>,
	"Rafael J . Wysocki" <rjw@sisk.pl>,
	Yijing Wang <wangyijing@huawei.com>,
	Xinwei Hu <huxinwei@huawei.com>, <linux-kernel@vger.kernel.org>,
	<linux-pci@vger.kernel.org>
Subject: Re: [RFC PATCH v1 21/22] PCI: cleanups for PCI bus lock implementation
Date: Wed, 12 Sep 2012 16:58:33 +0800	[thread overview]
Message-ID: <50504EB9.7000906@huawei.com> (raw)
In-Reply-To: <CAErSpo4ubTSu5cSrLVfs5UHc44KgtzO_OxL_QganfhqYn2hUWQ@mail.gmail.com>

On 2012-9-12 7:21, Bjorn Helgaas wrote:
> On Tue, Aug 7, 2012 at 10:11 AM, Jiang Liu <liuj97@gmail.com> wrote:
>> Now all Archs have been converted to the new PCI bus lock mechanism,
>> so clean up unused code.
> 
> When you say "all arches," do you really mean "x86 and ia64"?  I
> assume all the other architectures have similar issues.  Or is this
> somehow ACPI-specific?
Hi Bjorn,
	It's still RFC to give an overview of the whole patch set. 
Here I mean once we have enhanced all arches, we will apply following patches:)
I'm working to enhance all arches recently, and will post the latest patch
once it passes basic tests.
	Thanks!

> 
>> Signed-off-by: Jiang Liu <liuj97@gmail.com>
>> ---
>>  drivers/pci/Kconfig     |    3 ---
>>  drivers/pci/bus.c       |    1 -
>>  drivers/pci/pci-sysfs.c |    9 ---------
>>  drivers/pci/probe.c     |    4 +---
>>  include/linux/pci.h     |   10 ----------
>>  5 files changed, 1 insertion(+), 26 deletions(-)
>>
>> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
>> index 5a796c0..848bfb8 100644
>> --- a/drivers/pci/Kconfig
>> +++ b/drivers/pci/Kconfig
>> @@ -120,6 +120,3 @@ config PCI_IOAPIC
>>  config PCI_LABEL
>>         def_bool y if (DMI || ACPI)
>>         select NLS
>> -
>> -config PCI_BUS_LOCK
>> -       def_bool y if (X86 || IA64)
>> diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
>> index 371f20a..308c376 100644
>> --- a/drivers/pci/bus.c
>> +++ b/drivers/pci/bus.c
>> @@ -196,7 +196,6 @@ int pci_bus_add_child(struct pci_bus *bus)
>>                         pci_create_legacy_files(bus);
>>                         pci_bus_change_state(bus, PCI_BUS_STATE_INITIALIZED,
>>                                         PCI_BUS_STATE_WORKING, false);
>> -                       bus->is_added = 1;
>>                 }
>>         }
>>
>> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
>> index 11043b4..a5a4195 100644
>> --- a/drivers/pci/pci-sysfs.c
>> +++ b/drivers/pci/pci-sysfs.c
>> @@ -284,7 +284,6 @@ msi_bus_store(struct device *dev, struct device_attribute *attr,
>>  }
>>
>>  #ifdef CONFIG_HOTPLUG
>> -static DEFINE_MUTEX(pci_remove_rescan_mutex);
>>  static ssize_t bus_rescan_store(struct bus_type *bus, const char *buf,
>>                                 size_t count)
>>  {
>> @@ -296,13 +295,11 @@ static ssize_t bus_rescan_store(struct bus_type *bus, const char *buf,
>>
>>         if (val) {
>>                 pci_host_bridge_hotplug_lock();
>> -               mutex_lock(&pci_remove_rescan_mutex);
>>                 while ((b = pci_find_next_bus(b)) != NULL)
>>                         if (pci_bus_lock_states(b, PCI_BUS_STATE_WORKING) > 0) {
>>                                 pci_rescan_bus(b);
>>                                 pci_bus_unlock(b);
>>                         }
>> -               mutex_unlock(&pci_remove_rescan_mutex);
>>                 pci_host_bridge_hotplug_unlock();
>>         }
>>         return count;
>> @@ -326,13 +323,11 @@ dev_rescan_store(struct device *dev, struct device_attribute *attr,
>>         if (val) {
>>                 struct pci_bus *bus = pdev->bus;
>>
>> -               mutex_lock(&pci_remove_rescan_mutex);
>>                 if (pci_bus_lock_states(bus, PCI_BUS_STATE_WORKING) > 0) {
>>                         if (pdev->is_added)
>>                                 pci_rescan_bus(bus);
>>                         pci_bus_unlock(bus);
>>                 }
>> -               mutex_unlock(&pci_remove_rescan_mutex);
>>         }
>>         return count;
>>  }
>> @@ -342,13 +337,11 @@ static void remove_callback(struct device *dev)
>>         struct pci_dev *pdev = to_pci_dev(dev);
>>         struct pci_bus *bus = pdev->bus;
>>
>> -       mutex_lock(&pci_remove_rescan_mutex);
>>         if (pci_bus_lock_states(bus, PCI_BUS_STATE_WORKING) > 0) {
>>                 pci_bus_get(bus);
>>                 pci_stop_and_remove_bus_device(pdev);
>>                 pci_unlock_and_put_bus(bus);
>>         }
>> -       mutex_unlock(&pci_remove_rescan_mutex);
>>  }
>>
>>  static ssize_t
>> @@ -382,14 +375,12 @@ dev_bus_rescan_store(struct device *dev, struct device_attribute *attr,
>>                 return -EINVAL;
>>
>>         if (val) {
>> -               mutex_lock(&pci_remove_rescan_mutex);
>>                 if (!pci_is_root_bus(bus))
>>                         pci_rescan_bus_bridge_resize(bus->self);
>>                 else if (pci_bus_lock_states(bus, PCI_BUS_STATE_WORKING) > 0) {
>>                         pci_rescan_bus(bus);
>>                         pci_bus_unlock(bus);
>>                 }
>> -               mutex_unlock(&pci_remove_rescan_mutex);
>>         }
>>         return count;
>>  }
>> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
>> index da6f04c..09517c3 100644
>> --- a/drivers/pci/probe.c
>> +++ b/drivers/pci/probe.c
>> @@ -1626,11 +1626,9 @@ unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus)
>>         if (pci_bus_get_state(bus) < PCI_BUS_STATE_WORKING) {
>>                 dev_dbg(&bus->dev, "fixups for bus\n");
>>                 pcibios_fixup_bus(bus);
>> -               if (pci_is_root_bus(bus)) {
>> +               if (pci_is_root_bus(bus))
>>                         pci_bus_change_state(bus, PCI_BUS_STATE_REGISTERED,
>>                                              PCI_BUS_STATE_WORKING, false);
>> -                       bus->is_added = 1;
>> -               }
>>         }
>>
>>         for (pass=0; pass < 2; pass++)
>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>> index 9e52e88..0e50ec8 100644
>> --- a/include/linux/pci.h
>> +++ b/include/linux/pci.h
>> @@ -442,7 +442,6 @@ struct pci_bus {
>>         struct device           dev;
>>         struct bin_attribute    *legacy_io; /* legacy I/O for this bus */
>>         struct bin_attribute    *legacy_mem; /* legacy mem */
>> -       unsigned int            is_added:1;
>>         atomic_t                state;
>>  };
>>
>> @@ -463,21 +462,12 @@ struct pci_bus {
>>  #define        PCI_BUS_STATE_DESTROYED         0x40    /* invalid state */
>>  #define        PCI_BUS_STATE_MASK              0x7F
>>
>> -#ifdef CONFIG_PCI_BUS_LOCK
>>  #define        PCI_BUS_STATE_LOCK              0x10000 /* for pci core only */
>>
>>  static inline bool pci_bus_is_locked(struct pci_bus *bus)
>>  {
>>         return !!(atomic_read(&bus->state) & PCI_BUS_STATE_LOCK);
>>  }
>> -#else /* CONFIG_PCI_BUS_LOCK */
>> -#define        PCI_BUS_STATE_LOCK              0x0000  /* for pci core only */
>> -
>> -static inline bool pci_bus_is_locked(struct pci_bus *bus)
>> -{
>> -       return true;
>> -}
>> -#endif /* CONFIG_PCI_BUS_LOCK */
>>
>>  static inline int pci_bus_get_state(struct pci_bus *bus)
>>  {
>> --
>> 1.7.9.5
>>
> 
> .
>