[PATCH v3 2/3] Use kacpi_hotplug_wq to handle container hotplug event.
From: Tang Chen <hidden>
Date: 2012-10-31 07:29:20
Also in:
linux-pci, lkml
Subsystem:
acpi, the rest · Maintainers:
"Rafael J. Wysocki", Linus Torvalds
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 <redacted>
---
drivers/acpi/container.c | 34 ++++++++++++++++++++++++++++++----
1 files changed, 30 insertions(+), 4 deletions(-)
diff --git a/drivers/acpi/container.c b/drivers/acpi/container.c
index 69e2d6b..a10eee6 100644
--- a/drivers/acpi/container.c
+++ b/drivers/acpi/container.c@@ -35,6 +35,7 @@ #include <acpi/acpi_bus.h> #include <acpi/acpi_drivers.h> #include <acpi/container.h> +#include <acpi/acpiosxf.h> #define PREFIX "ACPI: "
@@ -165,14 +166,22 @@ 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) +/* This function is of type acpi_osd_exec_callback */ +static void _container_notify_cb(void *context) { struct acpi_device *device = NULL; int result; int present; acpi_status status; + struct acpi_hp_cb_data *cb_data; + acpi_handle handle; + u32 type; u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */ + cb_data = (struct acpi_hp_cb_data *)context; + handle = cb_data->handle; + type = cb_data->type; + switch (type) { case ACPI_NOTIFY_BUS_CHECK: /* Fall through */
@@ -188,7 +197,7 @@ static void container_notify_cb(acpi_handle handle, u32 type, void *context) /* device exist and this is a remove request */ device->flags.eject_pending = 1; kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE); - return; + goto out; } break; }
@@ -210,20 +219,37 @@ static void container_notify_cb(acpi_handle handle, u32 type, void *context) if (!acpi_bus_get_device(handle, &device) && device) { device->flags.eject_pending = 1; kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE); - return; + goto out; } break; default: /* non-hotplug event; possibly handled by other handler */ - return; + goto out; } /* Inform firmware that the hotplug operation has completed */ (void) acpi_evaluate_hotplug_ost(handle, type, ost_code, NULL); + +out: + kfree(context); /* allocated in container_notify_cb */ return; } +static void container_notify_cb(acpi_handle handle, u32 type, + void *context) +{ + /* + * Currently the code adds all hotplug events to the kacpid_wq + * queue when it should add hotplug events to the kacpi_hotplug_wq. + * The proper way to fix this is to reorganize the code so that + * drivers (dock, etc.) do not call acpi_os_execute(), etc. + * For now just re-add this work to the kacpi_hotplug_wq so we + * don't deadlock on hotplug actions. + */ + acpi_hp_cb_execute(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