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 <tangc...@cn.fujitsu.com>
---
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
--
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