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Message-Id: <20220324213445.3055538-1-tansuresh@google.com>
Date: Thu, 24 Mar 2022 14:34:45 -0700
From: Tanjore Suresh <tansuresh@...gle.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Rafael J . Wysocki" <rafael@...nel.org>
Cc: linux-kernel@...r.kernel.org, trivial@...nel.org,
Tanjore Suresh <tansuresh@...gle.com>
Subject: [PATCH 1/3] driver core: Support asynchronous driver shutdown
This changes the bus driver interface to take in a flag to indicate
whether a bus and associated devices are willing to participate in
the asynchronous shutdown. If this flag is not set bus driver
implementation will follow synchronous shutdown semantics.
Signed-off-by: Tanjore Suresh <tansuresh@...gle.com>
---
drivers/base/core.c | 39 +++++++++++++++++++++++++++++++++++++-
include/linux/device/bus.h | 10 ++++++++++
2 files changed, 48 insertions(+), 1 deletion(-)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 3d6430eb0c6a..359e7067e8b8 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -4479,6 +4479,7 @@ EXPORT_SYMBOL_GPL(device_change_owner);
void device_shutdown(void)
{
struct device *dev, *parent;
+ LIST_HEAD(async_shutdown_list);
wait_for_device_probe();
device_block_probing();
@@ -4523,7 +4524,14 @@ void device_shutdown(void)
dev_info(dev, "shutdown_pre\n");
dev->class->shutdown_pre(dev);
}
- if (dev->bus && dev->bus->shutdown) {
+
+ if (dev->bus && dev->bus->shutdown_pre) {
+ if (initcall_debug)
+ dev_info(dev, "shutdown_pre\n");
+ dev->bus->shutdown_pre(dev);
+ list_add(&dev->kobj.entry,
+ &async_shutdown_list);
+ } else if (dev->bus && dev->bus->shutdown) {
if (initcall_debug)
dev_info(dev, "shutdown\n");
dev->bus->shutdown(dev);
@@ -4543,6 +4551,35 @@ void device_shutdown(void)
spin_lock(&devices_kset->list_lock);
}
spin_unlock(&devices_kset->list_lock);
+
+ /*
+ * Second pass spin for only devices, that have configured
+ * Asynchronous shutdown.
+ */
+ while (!list_empty(&async_shutdown_list)) {
+ dev = list_entry(async_shutdown_list.next, struct device,
+ kobj.entry);
+ parent = get_device(dev->parent);
+ get_device(dev);
+ /*
+ * Make sure the device is off the list
+ */
+ list_del_init(&dev->kobj.entry);
+ if (parent)
+ device_lock(parent);
+ device_lock(dev);
+ if (dev->bus && dev->bus->shutdown_post) {
+ if (initcall_debug)
+ dev_info(dev,
+ "shutdown_post called\n");
+ dev->bus->shutdown_post(dev);
+ }
+ device_unlock(dev);
+ if (parent)
+ device_unlock(parent);
+ put_device(dev);
+ put_device(parent);
+ }
}
/*
diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h
index a039ab809753..e261819601e9 100644
--- a/include/linux/device/bus.h
+++ b/include/linux/device/bus.h
@@ -49,6 +49,14 @@ struct fwnode_handle;
* will never get called until they do.
* @remove: Called when a device removed from this bus.
* @shutdown: Called at shut-down time to quiesce the device.
+ * @shutdown_pre: Called at the shutdown-time to start the shutdown
+ * process on the device. This entry point will be called
+ * only when the bus driver has indicated it would like
+ * to participate in asynchronous shutdown completion.
+ * @shutdown_post: Called at shutdown-time to complete the shutdown
+ * process of the device. This entry point will be called
+ * only when the bus drive has indicated it would like to
+ * participate in the asynchronous shutdown completion.
*
* @online: Called to put the device back online (after offlining it).
* @offline: Called to put the device offline for hot-removal. May fail.
@@ -93,6 +101,8 @@ struct bus_type {
void (*sync_state)(struct device *dev);
void (*remove)(struct device *dev);
void (*shutdown)(struct device *dev);
+ void (*shutdown_pre)(struct device *dev);
+ void (*shutdown_post)(struct device *dev);
int (*online)(struct device *dev);
int (*offline)(struct device *dev);
--
2.35.1.1021.g381101b075-goog
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