Messages in this thread Patch in this message | | | Date | Thu, 24 Mar 2022 14:34:45 -0700 | Subject | [PATCH 1/3] driver core: Support asynchronous driver shutdown | From | Tanjore Suresh <> |
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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@google.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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