[PATCH v5] acpi: Fix CPU hot removal problem

[PATCH v5] acpi: Fix CPU hot removal problem

[canquan.shen]

We run linux as a guest in Xen environment. When we used the xen tools
(xm vcpu-set <n>) to hot add and remove vcpu to and from the guest, we
encountered the failure on vcpu removal. We found the reason is that it
did't go to really remove cpu in the cpu removal code path.

This patch adds acpi_bus_hot_remove_device in acpi_process_hotplug_notify to
fix this issue. With this patch, it works fine for us.

Signed-off-by: Canquan Shen <shencanquan@huawei.com>
---
  drivers/acpi/processor_driver.c |   13 +------------
  drivers/acpi/scan.c             |    4 ++--
  include/acpi/acpi_bus.h         |    1 +
  3 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/processor_driver.c 
b/drivers/acpi/processor_driver.c
index a4e0f1b..8429688 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -665,18 +665,7 @@ static void 
acpi_processor_hotplug_notify(acpi_handle handle,
  	case ACPI_NOTIFY_EJECT_REQUEST:
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  				  "received ACPI_NOTIFY_EJECT_REQUEST\n"));
-
-		if (acpi_bus_get_device(handle, &device)) {
-			printk(KERN_ERR PREFIX
-				    "Device don't exist, dropping EJECT\n");
-			break;
-		}
-		pr = acpi_driver_data(device);
-		if (!pr) {
-			printk(KERN_ERR PREFIX
-				    "Driver data is NULL, dropping EJECT\n");
-			return;
-		}
+		acpi_bus_hot_remove_device(handle);
  		break;
  	default:
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 449c556..6dfb4a7 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -83,7 +83,7 @@ acpi_device_modalias_show(struct device *dev, struct 
device_attribute *attr, cha
  }
  static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);

-static void acpi_bus_hot_remove_device(void *context)
+void acpi_bus_hot_remove_device(void *context)
  {
  	struct acpi_device *device;
  	acpi_handle handle = context;
@@ -129,7 +129,7 @@ static void acpi_bus_hot_remove_device(void *context)
  	 * TBD: _EJD support.
  	 */
  	status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
-	if (ACPI_FAILURE(status))
+	if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND))
  		printk(KERN_WARNING PREFIX
  				"Eject device failed\n");

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 6cd5b64..756e8d1 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -342,6 +342,7 @@ int acpi_match_device_ids(struct acpi_device *device,
  			  const struct acpi_device_id *ids);
  int acpi_create_dir(struct acpi_device *);
  void acpi_remove_dir(struct acpi_device *);
+void acpi_bus_hot_remove_device(void *context);

  /*
   * Bind physical devices with ACPI devices
-- 
1.7.6.msysgit.0

Re: [PATCH v5] acpi: Fix CPU hot removal problem

[Chen Gong]

于 2011/9/24 14:10, canquan.shen 写道:
> We run linux as a guest in Xen environment. When we used the xen tools
> (xm vcpu-set <n>) to hot add and remove vcpu to and from the guest, we
> encountered the failure on vcpu removal. We found the reason is that it
> did't go to really remove cpu in the cpu removal code path.
>
> This patch adds acpi_bus_hot_remove_device in acpi_process_hotplug_notify to
> fix this issue. With this patch, it works fine for us.
>
> Signed-off-by: Canquan Shen <shencanquan@huawei.com>
> ---
> drivers/acpi/processor_driver.c | 13 +------------
> drivers/acpi/scan.c | 4 ++--
> include/acpi/acpi_bus.h | 1 +
> 3 files changed, 4 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
> index a4e0f1b..8429688 100644
> --- a/drivers/acpi/processor_driver.c
> +++ b/drivers/acpi/processor_driver.c
> @@ -665,18 +665,7 @@ static void acpi_processor_hotplug_notify(acpi_handle handle,
> case ACPI_NOTIFY_EJECT_REQUEST:
> ACPI_DEBUG_PRINT((ACPI_DB_INFO,
> "received ACPI_NOTIFY_EJECT_REQUEST\n"));
> -
> - if (acpi_bus_get_device(handle, &device)) {
> - printk(KERN_ERR PREFIX
> - "Device don't exist, dropping EJECT\n");
> - break;
> - }
> - pr = acpi_driver_data(device);
> - if (!pr) {
> - printk(KERN_ERR PREFIX
> - "Driver data is NULL, dropping EJECT\n");
> - return;
> - }
> + acpi_bus_hot_remove_device(handle);

As the description in __acpi_os_execute(in acpi_os_hotplug_execute),
         /*
          * We can't run hotplug code in keventd_wq/kacpid_wq/kacpid_notify_wq
          * because the hotplug code may call driver .remove() functions,
          * which invoke flush_scheduled_work/acpi_os_wait_events_complete
          * to flush these workqueues.
          */
If so, why not using following call:

acpi_os_hotplug_execute(acpi_bus_hot_remove_device, acpi_device->handle);

Re: [PATCH v5] acpi: Fix CPU hot removal problem

[canquan.shen]

On 2011/9/29 11:14, Chen Gong wrote:
> 于 2011/9/24 14:10, canquan.shen 写道:
>> We run linux as a guest in Xen environment. When we used the xen tools
>> (xm vcpu-set <n>) to hot add and remove vcpu to and from the guest, we
>> encountered the failure on vcpu removal. We found the reason is that it
>> did't go to really remove cpu in the cpu removal code path.
>>
>> This patch adds acpi_bus_hot_remove_device in
>> acpi_process_hotplug_notify to
>> fix this issue. With this patch, it works fine for us.
>>
>> Signed-off-by: Canquan Shen <shencanquan@huawei.com>
>> ---
>> drivers/acpi/processor_driver.c | 13 +------------
>> drivers/acpi/scan.c | 4 ++--
>> include/acpi/acpi_bus.h | 1 +
>> 3 files changed, 4 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/acpi/processor_driver.c
>> b/drivers/acpi/processor_driver.c
>> index a4e0f1b..8429688 100644
>> --- a/drivers/acpi/processor_driver.c
>> +++ b/drivers/acpi/processor_driver.c
>> @@ -665,18 +665,7 @@ static void
>> acpi_processor_hotplug_notify(acpi_handle handle,
>> case ACPI_NOTIFY_EJECT_REQUEST:
>> ACPI_DEBUG_PRINT((ACPI_DB_INFO,
>> "received ACPI_NOTIFY_EJECT_REQUEST\n"));
>> -
>> - if (acpi_bus_get_device(handle, &device)) {
>> - printk(KERN_ERR PREFIX
>> - "Device don't exist, dropping EJECT\n");
>> - break;
>> - }
>> - pr = acpi_driver_data(device);
>> - if (!pr) {
>> - printk(KERN_ERR PREFIX
>> - "Driver data is NULL, dropping EJECT\n");
>> - return;
>> - }
>> + acpi_bus_hot_remove_device(handle);
>
> As the description in __acpi_os_execute(in acpi_os_hotplug_execute),
> /*
> * We can't run hotplug code in keventd_wq/kacpid_wq/kacpid_notify_wq
> * because the hotplug code may call driver .remove() functions,
> * which invoke flush_scheduled_work/acpi_os_wait_events_complete
> * to flush these workqueues.
> */
> If so, why not using following call:
>
> acpi_os_hotplug_execute(acpi_bus_hot_remove_device, acpi_device->handle);
>
>

It is ok if using the acpi_os_hotplug_execute. but it is complex and 
more time for removal cpu because it is add to queue and some time the 
work will be called.
I think that it is clear to call directly acpi_bus_hot_remove_device 
function in acpi_processor_hotplug_notify.


> --
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>
> .
>

Re: [PATCH v5] acpi: Fix CPU hot removal problem

[Bjorn Helgaas]

On Wed, Sep 28, 2011 at 9:41 PM, canquan.shen <shencanquan@huawei.com> wrote:
>
> On 2011/9/29 11:14, Chen Gong wrote:
>>
>> 于 2011/9/24 14:10, canquan.shen 写道:
>>>
>>> We run linux as a guest in Xen environment. When we used the xen tools
>>> (xm vcpu-set <n>) to hot add and remove vcpu to and from the guest, we
>>> encountered the failure on vcpu removal. We found the reason is that it
>>> did't go to really remove cpu in the cpu removal code path.
>>>
>>> This patch adds acpi_bus_hot_remove_device in
>>> acpi_process_hotplug_notify to
>>> fix this issue. With this patch, it works fine for us.
>>>
>>> Signed-off-by: Canquan Shen <shencanquan@huawei.com>
>>> ---
>>> drivers/acpi/processor_driver.c | 13 +------------
>>> drivers/acpi/scan.c | 4 ++--
>>> include/acpi/acpi_bus.h | 1 +
>>> 3 files changed, 4 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/drivers/acpi/processor_driver.c
>>> b/drivers/acpi/processor_driver.c
>>> index a4e0f1b..8429688 100644
>>> --- a/drivers/acpi/processor_driver.c
>>> +++ b/drivers/acpi/processor_driver.c
>>> @@ -665,18 +665,7 @@ static void
>>> acpi_processor_hotplug_notify(acpi_handle handle,
>>> case ACPI_NOTIFY_EJECT_REQUEST:
>>> ACPI_DEBUG_PRINT((ACPI_DB_INFO,
>>> "received ACPI_NOTIFY_EJECT_REQUEST\n"));
>>> -
>>> - if (acpi_bus_get_device(handle, &device)) {
>>> - printk(KERN_ERR PREFIX
>>> - "Device don't exist, dropping EJECT\n");
>>> - break;
>>> - }
>>> - pr = acpi_driver_data(device);
>>> - if (!pr) {
>>> - printk(KERN_ERR PREFIX
>>> - "Driver data is NULL, dropping EJECT\n");
>>> - return;
>>> - }
>>> + acpi_bus_hot_remove_device(handle);
>>
>> As the description in __acpi_os_execute(in acpi_os_hotplug_execute),
>> /*
>> * We can't run hotplug code in keventd_wq/kacpid_wq/kacpid_notify_wq
>> * because the hotplug code may call driver .remove() functions,
>> * which invoke flush_scheduled_work/acpi_os_wait_events_complete
>> * to flush these workqueues.
>> */
>> If so, why not using following call:
>>
>> acpi_os_hotplug_execute(acpi_bus_hot_remove_device, acpi_device->handle);
>>
>>
>
> It is ok if using the acpi_os_hotplug_execute. but it is complex and more time for removal cpu because it is add to queue and some time the work will be called.
> I think that it is clear to call directly acpi_bus_hot_remove_device function in acpi_processor_hotplug_notify.

Chen, you're right that the CPU hot-remove notifier is running in a
workqueue, we are proposing  that the notifier call
acpi_bus_hot_remove_device(), which calls the .remove() method, and
that can cause a deadlock if .remove() waits for the workqueue to be
flushed.

The usual way this deadlock happens is when the .remove() method uses
acpi_remove_notify_handler().  But the processor_driver .remove()
method doesn't do anything with notify handler registration; the
handler is registered/unregistered by the module init/exit functions.
So I don't think we need to use acpi_os_hotplug_execute() in this case
because I don't think there's a risk of deadlock.

However, if new CPU devices appear in the namespace after module-init,
I don't think processor_driver will handle them correctly.  This looks
like just another artifact of our screwed-up ACPI hotplug handling.

Bjorn

Re: [PATCH v5] acpi: Fix CPU hot removal problem

[canquan.shen]

Hi Len and Chen Gong,
    What's you opinion on this patch?

    Thanks.

---
canquan.shen
2011-10-18

On 2011/9/30 13:20, Bjorn Helgaas wrote:
> On Wed, Sep 28, 2011 at 9:41 PM, canquan.shen<shencanquan@huawei.com>  wrote:
>>
>> On 2011/9/29 11:14, Chen Gong wrote:
>>>
>>> 于 2011/9/24 14:10, canquan.shen 写道:
>>>>
>>>> We run linux as a guest in Xen environment. When we used the xen tools
>>>> (xm vcpu-set<n>) to hot add and remove vcpu to and from the guest, we
>>>> encountered the failure on vcpu removal. We found the reason is that it
>>>> did't go to really remove cpu in the cpu removal code path.
>>>>
>>>> This patch adds acpi_bus_hot_remove_device in
>>>> acpi_process_hotplug_notify to
>>>> fix this issue. With this patch, it works fine for us.
>>>>
>>>> Signed-off-by: Canquan Shen<shencanquan@huawei.com>
>>>> ---
>>>> drivers/acpi/processor_driver.c | 13 +------------
>>>> drivers/acpi/scan.c | 4 ++--
>>>> include/acpi/acpi_bus.h | 1 +
>>>> 3 files changed, 4 insertions(+), 14 deletions(-)
>>>>
>>>> diff --git a/drivers/acpi/processor_driver.c
>>>> b/drivers/acpi/processor_driver.c
>>>> index a4e0f1b..8429688 100644
>>>> --- a/drivers/acpi/processor_driver.c
>>>> +++ b/drivers/acpi/processor_driver.c
>>>> @@ -665,18 +665,7 @@ static void
>>>> acpi_processor_hotplug_notify(acpi_handle handle,
>>>> case ACPI_NOTIFY_EJECT_REQUEST:
>>>> ACPI_DEBUG_PRINT((ACPI_DB_INFO,
>>>> "received ACPI_NOTIFY_EJECT_REQUEST\n"));
>>>> -
>>>> - if (acpi_bus_get_device(handle,&device)) {
>>>> - printk(KERN_ERR PREFIX
>>>> - "Device don't exist, dropping EJECT\n");
>>>> - break;
>>>> - }
>>>> - pr = acpi_driver_data(device);
>>>> - if (!pr) {
>>>> - printk(KERN_ERR PREFIX
>>>> - "Driver data is NULL, dropping EJECT\n");
>>>> - return;
>>>> - }
>>>> + acpi_bus_hot_remove_device(handle);
>>>
>>> As the description in __acpi_os_execute(in acpi_os_hotplug_execute),
>>> /*
>>> * We can't run hotplug code in keventd_wq/kacpid_wq/kacpid_notify_wq
>>> * because the hotplug code may call driver .remove() functions,
>>> * which invoke flush_scheduled_work/acpi_os_wait_events_complete
>>> * to flush these workqueues.
>>> */
>>> If so, why not using following call:
>>>
>>> acpi_os_hotplug_execute(acpi_bus_hot_remove_device, acpi_device->handle);
>>>
>>>
>>
>> It is ok if using the acpi_os_hotplug_execute. but it is complex and more time for removal cpu because it is add to queue and some time the work will be called.
>> I think that it is clear to call directly acpi_bus_hot_remove_device function in acpi_processor_hotplug_notify.
>
> Chen, you're right that the CPU hot-remove notifier is running in a
> workqueue, we are proposing  that the notifier call
> acpi_bus_hot_remove_device(), which calls the .remove() method, and
> that can cause a deadlock if .remove() waits for the workqueue to be
> flushed.
>
> The usual way this deadlock happens is when the .remove() method uses
> acpi_remove_notify_handler().  But the processor_driver .remove()
> method doesn't do anything with notify handler registration; the
> handler is registered/unregistered by the module init/exit functions.
> So I don't think we need to use acpi_os_hotplug_execute() in this case
> because I don't think there's a risk of deadlock.
>
> However, if new CPU devices appear in the namespace after module-init,
> I don't think processor_driver will handle them correctly.  This looks
> like just another artifact of our screwed-up ACPI hotplug handling.
>
> Bjorn
>
> .
>

Re: [PATCH v5] acpi: Fix CPU hot removal problem

[Chen Gong]

于 2011/10/18 20:34, canquan.shen 写道:
> Hi Len and Chen Gong,
> What's you opinion on this patch?
>
> Thanks.

I'm OK to this patch. Myabe you can ask Bjorn
for his "signed-off-by"

Re: [PATCH v5] acpi: Fix CPU hot removal problem

[canquan.shen]

On 2011/10/19 11:01, Chen Gong wrote:
> 于 2011/10/18 20:34, canquan.shen 写道:
>> Hi Len and Chen Gong,
>> What's you opinion on this patch?
>>
>> Thanks.
>
> I'm OK to this patch. Myabe you can ask Bjorn
> for his "signed-off-by"
>
> .
>

Thanks, Chen Gong.

Hi Bjorn,

   What's you opinion on this patch?

Thanks.

Canquan.Shen
2011-10-19

Re: [PATCH v5] acpi: Fix CPU hot removal problem

[Bjorn Helgaas]

On Tue, Oct 18, 2011 at 9:12 PM, canquan.shen <shencanquan@huawei.com> wrote:
> On 2011/10/19 11:01, Chen Gong wrote:
>>
>> 于 2011/10/18 20:34, canquan.shen 写道:
>>>
>>> Hi Len and Chen Gong,
>>> What's you opinion on this patch?
>>>
>>> Thanks.
>>
>> I'm OK to this patch. Myabe you can ask Bjorn
>> for his "signed-off-by"
>>
>> .
>>
>
> Thanks, Chen Gong.
>
> Hi Bjorn,
>
>  What's you opinion on this patch?

Looks good to me.

Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>

[PATCH v5] acpi: Fix CPU hot removal problem

[canquan.shen]

[-- Attachment #1: Type: text/plain, Size: 2906 bytes --]

We run linux as a guest in Xen environment. When we used the xen tools 
(xm vcpu-set <n>) to hot add and remove vcpu to and from the guest, we 
encountered the failure on vcpu removal. We found the reason is that it 
did't go to really remove cpu in the cpu removal code path.

This patch adds acpi_bus_hot_remove_device in 
acpi_process_hotplug_notify to fix this issue. With this patch, it works 
fine for us.

Signed-off-by: Canquan Shen <shencanquan@huawei.com>
---
  drivers/acpi/processor_driver.c |   13 +------------
  drivers/acpi/scan.c             |    4 ++--
  include/acpi/acpi_bus.h         |    1 +
  3 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/processor_driver.c 
b/drivers/acpi/processor_driver.c
index a4e0f1b..8429688 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -665,18 +665,7 @@ static void 
acpi_processor_hotplug_notify(acpi_handle handle,
      case ACPI_NOTIFY_EJECT_REQUEST:
          ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                    "received ACPI_NOTIFY_EJECT_REQUEST\n"));
-
-        if (acpi_bus_get_device(handle, &device)) {
-            printk(KERN_ERR PREFIX
-                    "Device don't exist, dropping EJECT\n");
-            break;
-        }
-        pr = acpi_driver_data(device);
-        if (!pr) {
-            printk(KERN_ERR PREFIX
-                    "Driver data is NULL, dropping EJECT\n");
-            return;
-        }
+        acpi_bus_hot_remove_device(handle);
          break;
      default:
          ACPI_DEBUG_PRINT((ACPI_DB_INFO,
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 449c556..6dfb4a7 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -83,7 +83,7 @@ acpi_device_modalias_show(struct device *dev, struct 
device_attribute *attr, cha
  }
  static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);

-static void acpi_bus_hot_remove_device(void *context)
+void acpi_bus_hot_remove_device(void *context)
  {
      struct acpi_device *device;
      acpi_handle handle = context;
@@ -129,7 +129,7 @@ static void acpi_bus_hot_remove_device(void *context)
       * TBD: _EJD support.
       */
      status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
-    if (ACPI_FAILURE(status))
+    if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND))
          printk(KERN_WARNING PREFIX
                  "Eject device failed\n");

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 6cd5b64..756e8d1 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -342,6 +342,7 @@ int acpi_match_device_ids(struct acpi_device *device,
                const struct acpi_device_id *ids);
  int acpi_create_dir(struct acpi_device *);
  void acpi_remove_dir(struct acpi_device *);
+void acpi_bus_hot_remove_device(void *context);

  /*
   * Bind physical devices with ACPI devices
-- 
1.7.6.msysgit.0

[-- Attachment #2: 0001-acpi-Fix-CPU-hot-removal-problem.patch --]
[-- Type: text/plain, Size: 2903 bytes --]

>From e7795527be2e9b334dc5f3ac9fdba9eaac62a33b Mon Sep 17 00:00:00 2001
From: Shen canquan <shencanquan@huawei.com>
Date: Sat, 24 Sep 2011 14:00:52 +0800
Subject: [PATCH] acpi: Fix CPU hot removal problem

We run linux as a guest in Xen environment. When we used the xen tools (xm
vcpu-set <n>) to hot add and remove vcpu to and from the guest, we
encountered the failure on vcpu removal. We found the reason is that it
did't go to really remove cpu in the cpu removal code path.

This patch adds acpi_bus_hot_remove_device in acpi_process_hotplug_notify to
fix this issue. With this patch, it works fine for us.

Signed-off-by: Canquan Shen <shencanquan@huawei.com>
---
 drivers/acpi/processor_driver.c |   13 +------------
 drivers/acpi/scan.c             |    4 ++--
 include/acpi/acpi_bus.h         |    1 +
 3 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index a4e0f1b..8429688 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -665,18 +665,7 @@ static void acpi_processor_hotplug_notify(acpi_handle handle,
 	case ACPI_NOTIFY_EJECT_REQUEST:
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				  "received ACPI_NOTIFY_EJECT_REQUEST\n"));
-
-		if (acpi_bus_get_device(handle, &device)) {
-			printk(KERN_ERR PREFIX
-				    "Device don't exist, dropping EJECT\n");
-			break;
-		}
-		pr = acpi_driver_data(device);
-		if (!pr) {
-			printk(KERN_ERR PREFIX
-				    "Driver data is NULL, dropping EJECT\n");
-			return;
-		}
+		acpi_bus_hot_remove_device(handle);
 		break;
 	default:
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 449c556..6dfb4a7 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -83,7 +83,7 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha
 }
 static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);
 
-static void acpi_bus_hot_remove_device(void *context)
+void acpi_bus_hot_remove_device(void *context)
 {
 	struct acpi_device *device;
 	acpi_handle handle = context;
@@ -129,7 +129,7 @@ static void acpi_bus_hot_remove_device(void *context)
 	 * TBD: _EJD support.
 	 */
 	status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
-	if (ACPI_FAILURE(status))
+	if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND))
 		printk(KERN_WARNING PREFIX
 				"Eject device failed\n");
 
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 6cd5b64..756e8d1 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -342,6 +342,7 @@ int acpi_match_device_ids(struct acpi_device *device,
 			  const struct acpi_device_id *ids);
 int acpi_create_dir(struct acpi_device *);
 void acpi_remove_dir(struct acpi_device *);
+void acpi_bus_hot_remove_device(void *context);
 
 /*
  * Bind physical devices with ACPI devices
-- 
1.7.6.msysgit.0

Re: [PATCH v5] acpi: Fix CPU hot removal problem

[Len Brown]

It doesn't apply for me, and it looks white-space damaged.
Does it pass checkpatch.pl for you and apply for you?
Possibly an issue with my new gmail setup,
but it looks more like this was damaged at the source.


ERROR: code indent should use tabs where possible
#103: FILE: drivers/acpi/processor_driver.c:668:
+        acpi_bus_hot_remove_device(handle);$

WARNING: please, no spaces at the start of a line
#103: FILE: drivers/acpi/processor_driver.c:668:
+        acpi_bus_hot_remove_device(handle);$

WARNING: please, no spaces at the start of a line
#125: FILE: drivers/acpi/scan.c:132:
+    if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND))$

WARNING: suspect code indent for conditional statements (4, 9)
#125: FILE: drivers/acpi/scan.c:132:
+    if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND))
          printk(KERN_WARNING PREFIX

-- 
Len Brown, Intel Open Source Technology Center

Re: [PATCH v5] acpi: Fix CPU hot removal problem

[canquan.shen]

[-- Attachment #1: Type: text/plain, Size: 1198 bytes --]

On 2011/11/8 1:37, Len Brown wrote:
> It doesn't apply for me, and it looks white-space damaged.
> Does it pass checkpatch.pl for you and apply for you?
> Possibly an issue with my new gmail setup,
> but it looks more like this was damaged at the source.
>
>
> ERROR: code indent should use tabs where possible
> #103: FILE: drivers/acpi/processor_driver.c:668:
> +        acpi_bus_hot_remove_device(handle);$
>
> WARNING: please, no spaces at the start of a line
> #103: FILE: drivers/acpi/processor_driver.c:668:
> +        acpi_bus_hot_remove_device(handle);$
>
> WARNING: please, no spaces at the start of a line
> #125: FILE: drivers/acpi/scan.c:132:
> +    if (ACPI_FAILURE(status)&&  (status != AE_NOT_FOUND))$
>
> WARNING: suspect code indent for conditional statements (4, 9)
> #125: FILE: drivers/acpi/scan.c:132:
> +    if (ACPI_FAILURE(status)&&  (status != AE_NOT_FOUND))
>            printk(KERN_WARNING PREFIX
>


Hi Len,
    Because I copy the patch to the email and my git proxy is not ready 
in window.  Please use the attachment to apply. it passed by checkpatch.pl.
    I will install the git in linux server. and later I will use it to 
send the patch.

Thanks,
Canquan.shen



[-- Attachment #2: 0001-acpi-Fix-CPU-hot-removal-problem.patch --]
[-- Type: text/plain, Size: 2903 bytes --]

>From e7795527be2e9b334dc5f3ac9fdba9eaac62a33b Mon Sep 17 00:00:00 2001
From: Shen canquan <shencanquan@huawei.com>
Date: Sat, 24 Sep 2011 14:00:52 +0800
Subject: [PATCH] acpi: Fix CPU hot removal problem

We run linux as a guest in Xen environment. When we used the xen tools (xm
vcpu-set <n>) to hot add and remove vcpu to and from the guest, we
encountered the failure on vcpu removal. We found the reason is that it
did't go to really remove cpu in the cpu removal code path.

This patch adds acpi_bus_hot_remove_device in acpi_process_hotplug_notify to
fix this issue. With this patch, it works fine for us.

Signed-off-by: Canquan Shen <shencanquan@huawei.com>
---
 drivers/acpi/processor_driver.c |   13 +------------
 drivers/acpi/scan.c             |    4 ++--
 include/acpi/acpi_bus.h         |    1 +
 3 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index a4e0f1b..8429688 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -665,18 +665,7 @@ static void acpi_processor_hotplug_notify(acpi_handle handle,
 	case ACPI_NOTIFY_EJECT_REQUEST:
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				  "received ACPI_NOTIFY_EJECT_REQUEST\n"));
-
-		if (acpi_bus_get_device(handle, &device)) {
-			printk(KERN_ERR PREFIX
-				    "Device don't exist, dropping EJECT\n");
-			break;
-		}
-		pr = acpi_driver_data(device);
-		if (!pr) {
-			printk(KERN_ERR PREFIX
-				    "Driver data is NULL, dropping EJECT\n");
-			return;
-		}
+		acpi_bus_hot_remove_device(handle);
 		break;
 	default:
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 449c556..6dfb4a7 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -83,7 +83,7 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha
 }
 static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);
 
-static void acpi_bus_hot_remove_device(void *context)
+void acpi_bus_hot_remove_device(void *context)
 {
 	struct acpi_device *device;
 	acpi_handle handle = context;
@@ -129,7 +129,7 @@ static void acpi_bus_hot_remove_device(void *context)
 	 * TBD: _EJD support.
 	 */
 	status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
-	if (ACPI_FAILURE(status))
+	if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND))
 		printk(KERN_WARNING PREFIX
 				"Eject device failed\n");
 
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 6cd5b64..756e8d1 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -342,6 +342,7 @@ int acpi_match_device_ids(struct acpi_device *device,
 			  const struct acpi_device_id *ids);
 int acpi_create_dir(struct acpi_device *);
 void acpi_remove_dir(struct acpi_device *);
+void acpi_bus_hot_remove_device(void *context);
 
 /*
  * Bind physical devices with ACPI devices
-- 
1.7.6.msysgit.0