diff mbox series

[v7,08/16] ACPI: Add post_eject to struct acpi_scan_handler for cpu hotplug

Message ID 20240418135412.14730-9-Jonathan.Cameron@huawei.com (mailing list archive)
State Handled Elsewhere, archived
Headers show
Series ACPI/arm64: add support for virtual cpu hotplug | expand

Commit Message

Jonathan Cameron April 18, 2024, 1:54 p.m. UTC
From: James Morse <james.morse@arm.com>

struct acpi_scan_handler has a detach callback that is used to remove
a driver when a bus is changed. When interacting with an eject-request,
the detach callback is called before _EJ0.

This means the ACPI processor driver can't use _STA to determine if a
CPU has been made not-present, or some of the other _STA bits have been
changed. acpi_processor_remove() needs to know the value of _STA after
_EJ0 has been called.

Add a post_eject callback to struct acpi_scan_handler. This is called
after acpi_scan_hot_remove() has successfully called _EJ0. Because
acpi_scan_check_and_detach() also clears the handler pointer,
it needs to be told if the caller will go on to call
acpi_bus_post_eject(), so that acpi_device_clear_enumerated()
and clearing the handler pointer can be deferred.
An extra flag is added to flags field introduced in the previous
patch to achieve this.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Tested-by: Miguel Luis <miguel.luis@oracle.com>
Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Tested-by: Jianyong Wu <jianyong.wu@arm.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

----
v7:
 - No change.
v6:
 - Switch to flags.
Russell, you hadn't signed off on this when posting last time.
Do you want to insert a suitable tag now?
v5:
 - Rebase to take into account the changes to scan handling in the
   meantime.
---
 drivers/acpi/acpi_processor.c |  4 ++--
 drivers/acpi/scan.c           | 30 +++++++++++++++++++++++++++---
 include/acpi/acpi_bus.h       |  1 +
 3 files changed, 30 insertions(+), 5 deletions(-)

Comments

Rafael J. Wysocki April 22, 2024, 7:10 p.m. UTC | #1
On Thu, Apr 18, 2024 at 3:58 PM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
> From: James Morse <james.morse@arm.com>
>
> struct acpi_scan_handler has a detach callback that is used to remove
> a driver when a bus is changed. When interacting with an eject-request,
> the detach callback is called before _EJ0.
>
> This means the ACPI processor driver can't use _STA to determine if a
> CPU has been made not-present, or some of the other _STA bits have been
> changed. acpi_processor_remove() needs to know the value of _STA after
> _EJ0 has been called.
>
> Add a post_eject callback to struct acpi_scan_handler. This is called
> after acpi_scan_hot_remove() has successfully called _EJ0. Because
> acpi_scan_check_and_detach() also clears the handler pointer,
> it needs to be told if the caller will go on to call
> acpi_bus_post_eject(), so that acpi_device_clear_enumerated()
> and clearing the handler pointer can be deferred.
> An extra flag is added to flags field introduced in the previous
> patch to achieve this.
>
> Signed-off-by: James Morse <james.morse@arm.com>
> Reviewed-by: Joanthan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Gavin Shan <gshan@redhat.com>
> Tested-by: Miguel Luis <miguel.luis@oracle.com>
> Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
> Tested-by: Jianyong Wu <jianyong.wu@arm.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

No objections:

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

> ----
> v7:
>  - No change.
> v6:
>  - Switch to flags.
> Russell, you hadn't signed off on this when posting last time.
> Do you want to insert a suitable tag now?
> v5:
>  - Rebase to take into account the changes to scan handling in the
>    meantime.
> ---
>  drivers/acpi/acpi_processor.c |  4 ++--
>  drivers/acpi/scan.c           | 30 +++++++++++++++++++++++++++---
>  include/acpi/acpi_bus.h       |  1 +
>  3 files changed, 30 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index 4e65011e706c..beb1761db579 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -471,7 +471,7 @@ static int acpi_processor_add(struct acpi_device *device,
>
>  #ifdef CONFIG_ACPI_HOTPLUG_CPU
>  /* Removal */
> -static void acpi_processor_remove(struct acpi_device *device)
> +static void acpi_processor_post_eject(struct acpi_device *device)
>  {
>         struct acpi_processor *pr;
>
> @@ -639,7 +639,7 @@ static struct acpi_scan_handler processor_handler = {
>         .ids = processor_device_ids,
>         .attach = acpi_processor_add,
>  #ifdef CONFIG_ACPI_HOTPLUG_CPU
> -       .detach = acpi_processor_remove,
> +       .post_eject = acpi_processor_post_eject,
>  #endif
>         .hotplug = {
>                 .enabled = true,
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 1ec9677e6c2d..3ec54624664a 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -245,6 +245,7 @@ static int acpi_scan_try_to_offline(struct acpi_device *device)
>  }
>
>  #define ACPI_SCAN_CHECK_FLAG_STATUS    BIT(0)
> +#define ACPI_SCAN_CHECK_FLAG_EJECT     BIT(1)
>
>  static int acpi_scan_check_and_detach(struct acpi_device *adev, void *p)
>  {
> @@ -273,8 +274,6 @@ static int acpi_scan_check_and_detach(struct acpi_device *adev, void *p)
>         if (handler) {
>                 if (handler->detach)
>                         handler->detach(adev);
> -
> -               adev->handler = NULL;
>         } else {
>                 device_release_driver(&adev->dev);
>         }
> @@ -284,6 +283,28 @@ static int acpi_scan_check_and_detach(struct acpi_device *adev, void *p)
>          */
>         acpi_device_set_power(adev, ACPI_STATE_D3_COLD);
>         adev->flags.initialized = false;
> +
> +       /* For eject this is deferred to acpi_bus_post_eject() */
> +       if (!(flags & ACPI_SCAN_CHECK_FLAG_EJECT)) {
> +               adev->handler = NULL;
> +               acpi_device_clear_enumerated(adev);
> +       }
> +       return 0;
> +}
> +
> +static int acpi_bus_post_eject(struct acpi_device *adev, void *not_used)
> +{
> +       struct acpi_scan_handler *handler = adev->handler;
> +
> +       acpi_dev_for_each_child_reverse(adev, acpi_bus_post_eject, NULL);
> +
> +       if (handler) {
> +               if (handler->post_eject)
> +                       handler->post_eject(adev);
> +
> +               adev->handler = NULL;
> +       }
> +
>         acpi_device_clear_enumerated(adev);
>
>         return 0;
> @@ -301,6 +322,7 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
>         acpi_handle handle = device->handle;
>         unsigned long long sta;
>         acpi_status status;
> +       uintptr_t flags = ACPI_SCAN_CHECK_FLAG_EJECT;
>
>         if (device->handler && device->handler->hotplug.demand_offline) {
>                 if (!acpi_scan_is_offline(device, true))
> @@ -313,7 +335,7 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
>
>         acpi_handle_debug(handle, "Ejecting\n");
>
> -       acpi_bus_trim(device);
> +       acpi_scan_check_and_detach(device, (void *)flags);
>
>         acpi_evaluate_lck(handle, 0);
>         /*
> @@ -336,6 +358,8 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
>         } else if (sta & ACPI_STA_DEVICE_ENABLED) {
>                 acpi_handle_warn(handle,
>                         "Eject incomplete - status 0x%llx\n", sta);
> +       } else {
> +               acpi_bus_post_eject(device, NULL);
>         }
>
>         return 0;
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index e7796f373d0d..51a4b936f19e 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -129,6 +129,7 @@ struct acpi_scan_handler {
>         bool (*match)(const char *idstr, const struct acpi_device_id **matchid);
>         int (*attach)(struct acpi_device *dev, const struct acpi_device_id *id);
>         void (*detach)(struct acpi_device *dev);
> +       void (*post_eject)(struct acpi_device *dev);
>         void (*bind)(struct device *phys_dev);
>         void (*unbind)(struct device *phys_dev);
>         struct acpi_hotplug_profile hotplug;
> --
> 2.39.2
>
Hanjun Guo April 23, 2024, 12:06 p.m. UTC | #2
On 2024/4/18 21:54, Jonathan Cameron wrote:
> From: James Morse <james.morse@arm.com>
> 
> struct acpi_scan_handler has a detach callback that is used to remove
> a driver when a bus is changed. When interacting with an eject-request,
> the detach callback is called before _EJ0.
> 
> This means the ACPI processor driver can't use _STA to determine if a
> CPU has been made not-present, or some of the other _STA bits have been
> changed. acpi_processor_remove() needs to know the value of _STA after
> _EJ0 has been called.
> 
> Add a post_eject callback to struct acpi_scan_handler. This is called
> after acpi_scan_hot_remove() has successfully called _EJ0. Because
> acpi_scan_check_and_detach() also clears the handler pointer,
> it needs to be told if the caller will go on to call
> acpi_bus_post_eject(), so that acpi_device_clear_enumerated()
> and clearing the handler pointer can be deferred.
> An extra flag is added to flags field introduced in the previous
> patch to achieve this.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> Reviewed-by: Joanthan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Gavin Shan <gshan@redhat.com>
> Tested-by: Miguel Luis <miguel.luis@oracle.com>
> Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
> Tested-by: Jianyong Wu <jianyong.wu@arm.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Jonathan Cameron April 26, 2024, 11:48 a.m. UTC | #3
On Thu, 18 Apr 2024 14:54:04 +0100
Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote:

> From: James Morse <james.morse@arm.com>
> 
> struct acpi_scan_handler has a detach callback that is used to remove
> a driver when a bus is changed. When interacting with an eject-request,
> the detach callback is called before _EJ0.
> 
> This means the ACPI processor driver can't use _STA to determine if a
> CPU has been made not-present, or some of the other _STA bits have been
> changed. acpi_processor_remove() needs to know the value of _STA after
> _EJ0 has been called.
> 
> Add a post_eject callback to struct acpi_scan_handler. This is called
> after acpi_scan_hot_remove() has successfully called _EJ0. Because
> acpi_scan_check_and_detach() also clears the handler pointer,
> it needs to be told if the caller will go on to call
> acpi_bus_post_eject(), so that acpi_device_clear_enumerated()
> and clearing the handler pointer can be deferred.
> An extra flag is added to flags field introduced in the previous
> patch to achieve this.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> Reviewed-by: Joanthan Cameron <Jonathan.Cameron@huawei.com>

Gavin's earlier review showed I can't type.
Fixed up by dropping this RB seeing as I signed off anyway.

> Reviewed-by: Gavin Shan <gshan@redhat.com>
> Tested-by: Miguel Luis <miguel.luis@oracle.com>
> Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
> Tested-by: Jianyong Wu <jianyong.wu@arm.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>
diff mbox series

Patch

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 4e65011e706c..beb1761db579 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -471,7 +471,7 @@  static int acpi_processor_add(struct acpi_device *device,
 
 #ifdef CONFIG_ACPI_HOTPLUG_CPU
 /* Removal */
-static void acpi_processor_remove(struct acpi_device *device)
+static void acpi_processor_post_eject(struct acpi_device *device)
 {
 	struct acpi_processor *pr;
 
@@ -639,7 +639,7 @@  static struct acpi_scan_handler processor_handler = {
 	.ids = processor_device_ids,
 	.attach = acpi_processor_add,
 #ifdef CONFIG_ACPI_HOTPLUG_CPU
-	.detach = acpi_processor_remove,
+	.post_eject = acpi_processor_post_eject,
 #endif
 	.hotplug = {
 		.enabled = true,
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 1ec9677e6c2d..3ec54624664a 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -245,6 +245,7 @@  static int acpi_scan_try_to_offline(struct acpi_device *device)
 }
 
 #define ACPI_SCAN_CHECK_FLAG_STATUS	BIT(0)
+#define ACPI_SCAN_CHECK_FLAG_EJECT	BIT(1)
 
 static int acpi_scan_check_and_detach(struct acpi_device *adev, void *p)
 {
@@ -273,8 +274,6 @@  static int acpi_scan_check_and_detach(struct acpi_device *adev, void *p)
 	if (handler) {
 		if (handler->detach)
 			handler->detach(adev);
-
-		adev->handler = NULL;
 	} else {
 		device_release_driver(&adev->dev);
 	}
@@ -284,6 +283,28 @@  static int acpi_scan_check_and_detach(struct acpi_device *adev, void *p)
 	 */
 	acpi_device_set_power(adev, ACPI_STATE_D3_COLD);
 	adev->flags.initialized = false;
+
+	/* For eject this is deferred to acpi_bus_post_eject() */
+	if (!(flags & ACPI_SCAN_CHECK_FLAG_EJECT)) {
+		adev->handler = NULL;
+		acpi_device_clear_enumerated(adev);
+	}
+	return 0;
+}
+
+static int acpi_bus_post_eject(struct acpi_device *adev, void *not_used)
+{
+	struct acpi_scan_handler *handler = adev->handler;
+
+	acpi_dev_for_each_child_reverse(adev, acpi_bus_post_eject, NULL);
+
+	if (handler) {
+		if (handler->post_eject)
+			handler->post_eject(adev);
+
+		adev->handler = NULL;
+	}
+
 	acpi_device_clear_enumerated(adev);
 
 	return 0;
@@ -301,6 +322,7 @@  static int acpi_scan_hot_remove(struct acpi_device *device)
 	acpi_handle handle = device->handle;
 	unsigned long long sta;
 	acpi_status status;
+	uintptr_t flags = ACPI_SCAN_CHECK_FLAG_EJECT;
 
 	if (device->handler && device->handler->hotplug.demand_offline) {
 		if (!acpi_scan_is_offline(device, true))
@@ -313,7 +335,7 @@  static int acpi_scan_hot_remove(struct acpi_device *device)
 
 	acpi_handle_debug(handle, "Ejecting\n");
 
-	acpi_bus_trim(device);
+	acpi_scan_check_and_detach(device, (void *)flags);
 
 	acpi_evaluate_lck(handle, 0);
 	/*
@@ -336,6 +358,8 @@  static int acpi_scan_hot_remove(struct acpi_device *device)
 	} else if (sta & ACPI_STA_DEVICE_ENABLED) {
 		acpi_handle_warn(handle,
 			"Eject incomplete - status 0x%llx\n", sta);
+	} else {
+		acpi_bus_post_eject(device, NULL);
 	}
 
 	return 0;
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index e7796f373d0d..51a4b936f19e 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -129,6 +129,7 @@  struct acpi_scan_handler {
 	bool (*match)(const char *idstr, const struct acpi_device_id **matchid);
 	int (*attach)(struct acpi_device *dev, const struct acpi_device_id *id);
 	void (*detach)(struct acpi_device *dev);
+	void (*post_eject)(struct acpi_device *dev);
 	void (*bind)(struct device *phys_dev);
 	void (*unbind)(struct device *phys_dev);
 	struct acpi_hotplug_profile hotplug;