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Message-Id: <E1rVDmk-0027Yh-1E@rmk-PC.armlinux.org.uk>
Date: Wed, 31 Jan 2024 16:50:02 +0000
From: Russell King (Oracle) <rmk+kernel@...linux.org.uk>
To: linux-pm@...r.kernel.org,
loongarch@...ts.linux.dev,
linux-acpi@...r.kernel.org,
linux-arch@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-riscv@...ts.infradead.org,
kvmarm@...ts.linux.dev,
x86@...nel.org,
acpica-devel@...ts.linuxfoundation.org,
linux-csky@...r.kernel.org,
linux-doc@...r.kernel.org,
linux-ia64@...r.kernel.org,
linux-parisc@...r.kernel.org
Cc: Salil Mehta <salil.mehta@...wei.com>,
Jean-Philippe Brucker <jean-philippe@...aro.org>,
jianyong.wu@....com,
justin.he@....com,
James Morse <james.morse@....com>,
Jonathan Cameron <Jonathan.Cameron@...wei.com>,
"Rafael J. Wysocki" <rafael@...nel.org>
Subject: [PATCH RFC v4 05/15] ACPI: Add post_eject to struct acpi_scan_handler
for cpu hotplug
From: James Morse <james.morse@....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_bus_trim_one() 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. The existing not-used pointer is used for this.
Signed-off-by: James Morse <james.morse@....com>
Reviewed-by: Joanthan Cameron <Jonathan.Cameron@...wei.com>
Reviewed-by: Gavin Shan <gshan@...hat.com>
Tested-by: Miguel Luis <miguel.luis@...cle.com>
Tested-by: Vishnu Pajjuri <vishnu@...amperecomputing.com>
Tested-by: Jianyong Wu <jianyong.wu@....com>
---
Outstanding comments:
https://lore.kernel.org/r/20230914152809.00003152@Huawei.com
https://lore.kernel.org/r/c3ef8123-1fcc-7289-c475-c753de44d564@redhat.com
---
drivers/acpi/acpi_processor.c | 4 +--
drivers/acpi/scan.c | 52 ++++++++++++++++++++++++++++++-----
include/acpi/acpi_bus.h | 1 +
3 files changed, 48 insertions(+), 9 deletions(-)
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index fd8f3a0572cb..00809c3b09f7 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -459,7 +459,7 @@ 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;
@@ -627,7 +627,7 @@ 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 2c8ba4526278..e4f4542f29af 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -244,18 +244,28 @@ static int acpi_scan_try_to_offline(struct acpi_device *device)
return 0;
}
-static int acpi_bus_trim_one(struct acpi_device *adev, void *not_used)
+/**
+ * acpi_bus_trim_one() - Detach scan handlers and drivers from ACPI device
+ * objects.
+ * @adev: Root of the ACPI namespace scope to walk.
+ * @eject: Pointer to a bool that indicates if this was due to an
+ * eject-request.
+ *
+ * Must be called under acpi_scan_lock.
+ * If @eject points to true, clearing the device enumeration is deferred until
+ * acpi_bus_post_eject() is called.
+ */
+static int acpi_bus_trim_one(struct acpi_device *adev, void *eject)
{
struct acpi_scan_handler *handler = adev->handler;
+ bool is_eject = *(bool *)eject;
- acpi_dev_for_each_child_reverse(adev, acpi_bus_trim_one, NULL);
+ acpi_dev_for_each_child_reverse(adev, acpi_bus_trim_one, eject);
adev->flags.match_driver = false;
if (handler) {
if (handler->detach)
handler->detach(adev);
-
- adev->handler = NULL;
} else {
device_release_driver(&adev->dev);
}
@@ -265,7 +275,12 @@ static int acpi_bus_trim_one(struct acpi_device *adev, void *not_used)
*/
acpi_device_set_power(adev, ACPI_STATE_D3_COLD);
adev->flags.initialized = false;
- acpi_device_clear_enumerated(adev);
+
+ /* For eject this is deferred to acpi_bus_post_eject() */
+ if (!is_eject) {
+ adev->handler = NULL;
+ acpi_device_clear_enumerated(adev);
+ }
return 0;
}
@@ -278,15 +293,36 @@ static int acpi_bus_trim_one(struct acpi_device *adev, void *not_used)
*/
void acpi_bus_trim(struct acpi_device *adev)
{
- acpi_bus_trim_one(adev, NULL);
+ bool eject = false;
+
+ acpi_bus_trim_one(adev, &eject);
}
EXPORT_SYMBOL_GPL(acpi_bus_trim);
+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;
+}
+
static int acpi_scan_hot_remove(struct acpi_device *device)
{
acpi_handle handle = device->handle;
unsigned long long sta;
acpi_status status;
+ bool eject = true;
if (device->handler && device->handler->hotplug.demand_offline) {
if (!acpi_scan_is_offline(device, true))
@@ -299,7 +335,7 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
acpi_handle_debug(handle, "Ejecting\n");
- acpi_bus_trim(device);
+ acpi_bus_trim_one(device, &eject);
acpi_evaluate_lck(handle, 0);
/*
@@ -322,6 +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 e4d24d3f9abb..436e7e022e4e 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;
--
2.30.2
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