Hi,
The container hotplug handler container_notify_cb() didn't implement
the hot-remove functionality. So, these 2 patches implement it like
the following way:
patch 1. Do not use kacpid_wq/kacpid_notify_wq to handle container hotplug event,
use kacpi_hotplug_wq instead to avoid deadlock.
Doing this is to reuse acpi_bus_hot_remove_device() in container
hot-remove handling.
patch 2. Introduce a new function container_device_remove() to handle
ACPI_NOTIFY_EJECT_REQUEST event for container.
In __acpi_os_execute(), we have the following comments:
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.
Actually, I run into the deadlock caused by running hotplug code in
kacpid_wq/kacpid_notify_wq. And I'm not quite sure if I did the right
thing in patch1. So, please give some comments if you have a better idea.
This is based on Lu Yinghai's job.
git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git for-pci-split-pci-root-hp-2
Tang Chen (2):
Use kacpi_hotplug_wq to handle container hotplug event.
Container hot remove support.
drivers/acpi/container.c | 102 +++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 92 insertions(+), 10 deletions(-)
As the comments in __acpi_os_execute() said:
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.
we should keep the hotplug code in kacpi_hotplug_wq.
But we have the following call series in kernel now:
acpi_ev_queue_notify_request()
|--> acpi_os_execute()
|--> __acpi_os_execute(type, function, context, 0)
The last parameter 0 makes the container_notify_cb() executed in
kacpi_notify_wq or kacpid_wq. So, we need to put the real hotplug code
into kacpi_hotplug_wq.
Signed-off-by: Tang Chen <[email protected]>
---
drivers/acpi/container.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 43 insertions(+), 1 deletions(-)
diff --git a/drivers/acpi/container.c b/drivers/acpi/container.c
index 1f9f7d7..643657a 100644
--- a/drivers/acpi/container.c
+++ b/drivers/acpi/container.c
@@ -72,8 +72,36 @@ static struct acpi_driver acpi_container_driver = {
},
};
+struct acpi_container_hp_work {
+ struct work_struct work;
+ acpi_handle handle;
+ u32 type;
+ void *context;
+};
+
/*******************************************************************/
+static void alloc_acpi_container_hp_work(acpi_handle handle, u32 type,
+ void *context,
+ void (*func)(struct work_struct *work))
+{
+ struct acpi_container_hp_work *hp_work;
+ int ret;
+
+ hp_work = kmalloc(sizeof(*hp_work), GFP_KERNEL);
+ if (!hp_work)
+ return;
+
+ hp_work->handle = handle;
+ hp_work->type = type;
+ hp_work->context = context;
+
+ INIT_WORK(&hp_work->work, func);
+ ret = queue_work(kacpi_hotplug_wq, &hp_work->work);
+ if (!ret)
+ kfree(hp_work);
+}
+
static int is_device_present(acpi_handle handle)
{
acpi_handle temp;
@@ -152,14 +180,21 @@ static int container_device_add(struct acpi_device **device, acpi_handle handle)
return result;
}
-static void container_notify_cb(acpi_handle handle, u32 type, void *context)
+static void __container_notify_cb(struct work_struct *work)
{
struct acpi_device *device = NULL;
int result;
int present;
acpi_status status;
+ struct acpi_container_hp_work *hp_work;
+ acpi_handle handle;
+ u32 type;
u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
+ hp_work = container_of(work, struct acpi_container_hp_work, work);
+ handle = hp_work->handle;
+ type = hp_work->type;
+
switch (type) {
case ACPI_NOTIFY_BUS_CHECK:
/* Fall through */
@@ -211,6 +246,13 @@ static void container_notify_cb(acpi_handle handle, u32 type, void *context)
return;
}
+static void container_notify_cb(acpi_handle handle, u32 type,
+ void *context)
+{
+ alloc_acpi_container_hp_work(handle, type, context,
+ __container_notify_cb);
+}
+
static acpi_status
container_walk_namespace_cb(acpi_handle handle,
u32 lvl, void *context, void **rv)
--
1.7.1
This patch introduces a new function container_device_remove() to do
the container hot-remove job. It works like the following:
1. call acpi_bus_trim(device, 0) to stop the container device.
2. generate the KOBJ_OFFLINE uevent. (Did I do this correct ?)
3. call acpi_bus_hot_remove_device(), which will call acpi_bus_trim(device, 1)
to remove the container.
This patch is based on Lu Yinghai's work.
git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git for-pci-split-pci-root-hp-2
Signed-off-by: Tang Chen <[email protected]>
---
drivers/acpi/container.c | 58 ++++++++++++++++++++++++++++++++++++++-------
1 files changed, 49 insertions(+), 9 deletions(-)
diff --git a/drivers/acpi/container.c b/drivers/acpi/container.c
index 643657a..1de4672 100644
--- a/drivers/acpi/container.c
+++ b/drivers/acpi/container.c
@@ -180,6 +180,35 @@ static int container_device_add(struct acpi_device **device, acpi_handle handle)
return result;
}
+static int container_device_remove(struct acpi_device *device)
+{
+ int ret;
+ struct acpi_eject_event *ej_event;
+
+ ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
+ if (!ej_event)
+ return -ENOMEM;
+
+ ej_event->device = device;
+ ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
+
+ /* stop container device at first */
+ ret = acpi_bus_trim(device, 0);
+ printk(KERN_WARNING "acpi_bus_trim stop return %x\n", ret);
+ if (ret)
+ return ret;
+
+ /* event originated from ACPI eject notification */
+ device->flags.eject_pending = 1;
+
+ /* send the uevent before remove the device */
+ kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE);
+
+ acpi_bus_hot_remove_device(ej_event);
+
+ return 0;
+}
+
static void __container_notify_cb(struct work_struct *work)
{
struct acpi_device *device = NULL;
@@ -195,6 +224,9 @@ static void __container_notify_cb(struct work_struct *work)
handle = hp_work->handle;
type = hp_work->type;
+ present = is_device_present(handle);
+ status = acpi_bus_get_device(handle, &device);
+
switch (type) {
case ACPI_NOTIFY_BUS_CHECK:
/* Fall through */
@@ -203,13 +235,14 @@ static void __container_notify_cb(struct work_struct *work)
(type == ACPI_NOTIFY_BUS_CHECK) ?
"ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK");
- present = is_device_present(handle);
- status = acpi_bus_get_device(handle, &device);
if (!present) {
if (ACPI_SUCCESS(status)) {
/* device exist and this is a remove request */
- device->flags.eject_pending = 1;
- kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE);
+ result = container_device_remove(device);
+ if (result) {
+ printk(KERN_WARNING "Failed to remove container\n");
+ break;
+ }
return;
}
break;
@@ -229,12 +262,19 @@ static void __container_notify_cb(struct work_struct *work)
break;
case ACPI_NOTIFY_EJECT_REQUEST:
- if (!acpi_bus_get_device(handle, &device) && device) {
- device->flags.eject_pending = 1;
- kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE);
- return;
+ printk(KERN_WARNING "Container driver received %s event\n",
+ "ACPI_NOTIFY_EJECT_REQUEST");
+
+ if (!present || ACPI_FAILURE(status) || !device)
+ break;
+
+ result = container_device_remove(device);
+ if (result) {
+ printk(KERN_WARNING "Failed to remove container\n");
+ break;
}
- break;
+
+ return;
default:
/* non-hotplug event; possibly handled by other handler */
--
1.7.1
On Tue, Oct 23, 2012 at 6:10 AM, Tang Chen <[email protected]> wrote:
> As the comments in __acpi_os_execute() said:
>
> 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.
>
> we should keep the hotplug code in kacpi_hotplug_wq.
>
> But we have the following call series in kernel now:
> acpi_ev_queue_notify_request()
> |--> acpi_os_execute()
> |--> __acpi_os_execute(type, function, context, 0)
>
> The last parameter 0 makes the container_notify_cb() executed in
> kacpi_notify_wq or kacpid_wq. So, we need to put the real hotplug code
> into kacpi_hotplug_wq.
I had other patches that merge acpi_hp_work in acpiphp and pci_root_hp.
I just put them in to for-pci-split-pci-root-hp-2.
can you check them to see if you can use it?
Thanks
Yinghai
On Tue, 2012-10-23 at 21:10 +0800, Tang Chen wrote:
> As the comments in __acpi_os_execute() said:
>
> 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.
>
> we should keep the hotplug code in kacpi_hotplug_wq.
>
> But we have the following call series in kernel now:
> acpi_ev_queue_notify_request()
> |--> acpi_os_execute()
> |--> __acpi_os_execute(type, function, context, 0)
>
> The last parameter 0 makes the container_notify_cb() executed in
> kacpi_notify_wq or kacpid_wq. So, we need to put the real hotplug code
> into kacpi_hotplug_wq.
Hi Tang,
I am curious; is there a particular reason why you use
alloc_acpi_container_hp_work() instead of acpi_os_hotplug_execute(),
which is already there in the tree?
Thanks,
-Toshi
> Signed-off-by: Tang Chen <[email protected]>
> ---
> drivers/acpi/container.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
> 1 files changed, 43 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/acpi/container.c b/drivers/acpi/container.c
> index 1f9f7d7..643657a 100644
> --- a/drivers/acpi/container.c
> +++ b/drivers/acpi/container.c
> @@ -72,8 +72,36 @@ static struct acpi_driver acpi_container_driver = {
> },
> };
>
> +struct acpi_container_hp_work {
> + struct work_struct work;
> + acpi_handle handle;
> + u32 type;
> + void *context;
> +};
> +
> /*******************************************************************/
>
> +static void alloc_acpi_container_hp_work(acpi_handle handle, u32 type,
> + void *context,
> + void (*func)(struct work_struct *work))
> +{
> + struct acpi_container_hp_work *hp_work;
> + int ret;
> +
> + hp_work = kmalloc(sizeof(*hp_work), GFP_KERNEL);
> + if (!hp_work)
> + return;
> +
> + hp_work->handle = handle;
> + hp_work->type = type;
> + hp_work->context = context;
> +
> + INIT_WORK(&hp_work->work, func);
> + ret = queue_work(kacpi_hotplug_wq, &hp_work->work);
> + if (!ret)
> + kfree(hp_work);
> +}
> +
> static int is_device_present(acpi_handle handle)
> {
> acpi_handle temp;
> @@ -152,14 +180,21 @@ static int container_device_add(struct acpi_device **device, acpi_handle handle)
> return result;
> }
>
> -static void container_notify_cb(acpi_handle handle, u32 type, void *context)
> +static void __container_notify_cb(struct work_struct *work)
> {
> struct acpi_device *device = NULL;
> int result;
> int present;
> acpi_status status;
> + struct acpi_container_hp_work *hp_work;
> + acpi_handle handle;
> + u32 type;
> u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
>
> + hp_work = container_of(work, struct acpi_container_hp_work, work);
> + handle = hp_work->handle;
> + type = hp_work->type;
> +
> switch (type) {
> case ACPI_NOTIFY_BUS_CHECK:
> /* Fall through */
> @@ -211,6 +246,13 @@ static void container_notify_cb(acpi_handle handle, u32 type, void *context)
> return;
> }
>
> +static void container_notify_cb(acpi_handle handle, u32 type,
> + void *context)
> +{
> + alloc_acpi_container_hp_work(handle, type, context,
> + __container_notify_cb);
> +}
> +
> static acpi_status
> container_walk_namespace_cb(acpi_handle handle,
> u32 lvl, void *context, void **rv)
On 10/25/2012 01:33 AM, Toshi Kani wrote:
> On Tue, 2012-10-23 at 21:10 +0800, Tang Chen wrote:
>> As the comments in __acpi_os_execute() said:
>>
>> 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.
>>
>> we should keep the hotplug code in kacpi_hotplug_wq.
>>
>> But we have the following call series in kernel now:
>> acpi_ev_queue_notify_request()
>> |--> acpi_os_execute()
>> |--> __acpi_os_execute(type, function, context, 0)
>>
>> The last parameter 0 makes the container_notify_cb() executed in
>> kacpi_notify_wq or kacpid_wq. So, we need to put the real hotplug code
>> into kacpi_hotplug_wq.
>
> Hi Tang,
>
> I am curious; is there a particular reason why you use
> alloc_acpi_container_hp_work() instead of acpi_os_hotplug_execute(),
> which is already there in the tree?
Hi Toshi,
Thanks for telling me this. I didn't realize this function. :)
And yes, it is better.
Thanks. :)
>
> Thanks,
> -Toshi
>
>
>> Signed-off-by: Tang Chen<[email protected]>
>> ---
>> drivers/acpi/container.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
>> 1 files changed, 43 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/acpi/container.c b/drivers/acpi/container.c
>> index 1f9f7d7..643657a 100644
>> --- a/drivers/acpi/container.c
>> +++ b/drivers/acpi/container.c
>> @@ -72,8 +72,36 @@ static struct acpi_driver acpi_container_driver = {
>> },
>> };
>>
>> +struct acpi_container_hp_work {
>> + struct work_struct work;
>> + acpi_handle handle;
>> + u32 type;
>> + void *context;
>> +};
>> +
>> /*******************************************************************/
>>
>> +static void alloc_acpi_container_hp_work(acpi_handle handle, u32 type,
>> + void *context,
>> + void (*func)(struct work_struct *work))
>> +{
>> + struct acpi_container_hp_work *hp_work;
>> + int ret;
>> +
>> + hp_work = kmalloc(sizeof(*hp_work), GFP_KERNEL);
>> + if (!hp_work)
>> + return;
>> +
>> + hp_work->handle = handle;
>> + hp_work->type = type;
>> + hp_work->context = context;
>> +
>> + INIT_WORK(&hp_work->work, func);
>> + ret = queue_work(kacpi_hotplug_wq,&hp_work->work);
>> + if (!ret)
>> + kfree(hp_work);
>> +}
>> +
>> static int is_device_present(acpi_handle handle)
>> {
>> acpi_handle temp;
>> @@ -152,14 +180,21 @@ static int container_device_add(struct acpi_device **device, acpi_handle handle)
>> return result;
>> }
>>
>> -static void container_notify_cb(acpi_handle handle, u32 type, void *context)
>> +static void __container_notify_cb(struct work_struct *work)
>> {
>> struct acpi_device *device = NULL;
>> int result;
>> int present;
>> acpi_status status;
>> + struct acpi_container_hp_work *hp_work;
>> + acpi_handle handle;
>> + u32 type;
>> u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
>>
>> + hp_work = container_of(work, struct acpi_container_hp_work, work);
>> + handle = hp_work->handle;
>> + type = hp_work->type;
>> +
>> switch (type) {
>> case ACPI_NOTIFY_BUS_CHECK:
>> /* Fall through */
>> @@ -211,6 +246,13 @@ static void container_notify_cb(acpi_handle handle, u32 type, void *context)
>> return;
>> }
>>
>> +static void container_notify_cb(acpi_handle handle, u32 type,
>> + void *context)
>> +{
>> + alloc_acpi_container_hp_work(handle, type, context,
>> + __container_notify_cb);
>> +}
>> +
>> static acpi_status
>> container_walk_namespace_cb(acpi_handle handle,
>> u32 lvl, void *context, void **rv)
>
>
> --
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