fix a deadlock issue when poking "eject" file
"/sys/devices/LNXSYSTM:00/.../eject" is used to evaluate _EJx method
and eject a device in user space.
But system hangs when poking the "eject" file because that
the device hot-removal code invoke the driver .remove method which will
try to remove the "eject" file as a result.
Queues the hot-removal function for deferred execution in this patch.
http://bugzilla.kernel.org/show_bug.cgi?id=9772
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 6d85289..9a84ed2 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -6,6 +6,7 @@
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/acpi.h>
+#include <asm/signal.h>
#include <acpi/acpi_drivers.h>
#include <acpi/acinterp.h> /* for acpi_ex_eisa_id_to_string() */
@@ -92,17 +93,37 @@
}
static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);
-static int acpi_eject_operation(acpi_handle handle, int lockable)
+static int acpi_bus_hot_remove_device(void *context)
{
+ struct acpi_device *device;
+ acpi_handle handle = context;
struct acpi_object_list arg_list;
union acpi_object arg;
acpi_status status = AE_OK;
- /*
- * TBD: evaluate _PS3?
- */
+ if (acpi_bus_get_device(handle, &device))
+ return 0;
- if (lockable) {
+ if (!device)
+ return 0;
+
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+ "Hot-removing device %s...\n", device->dev.bus_id));
+
+
+ if (acpi_bus_trim(device, 1)) {
+ ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
+ "Removing device failed\n"));
+ return -1;
+ }
+
+ /* power off device */
+ status = acpi_evaluate_object(handle, "_PS3", NULL, NULL);
+ if (ACPI_FAILURE(status) && status != AE_NOT_FOUND)
+ ACPI_DEBUG_PRINT((ACPI_DB_WARN,
+ "Power-off device failed\n"));
+
+ if (device->flags.lockable) {
arg_list.count = 1;
arg_list.pointer = &arg;
arg.type = ACPI_TYPE_INTEGER;
@@ -118,24 +139,19 @@
/*
* TBD: _EJD support.
*/
-
status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
- if (ACPI_FAILURE(status)) {
- return (-ENODEV);
- }
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
- return (0);
+ return 0;
}
static ssize_t
acpi_eject_store(struct device *d, struct device_attribute *attr,
const char *buf, size_t count)
{
- int result;
int ret = count;
- int islockable;
acpi_status status;
- acpi_handle handle;
acpi_object_type type = 0;
struct acpi_device *acpi_device = to_acpi_device(d);
@@ -154,17 +170,9 @@
goto err;
}
- islockable = acpi_device->flags.lockable;
- handle = acpi_device->handle;
-
- result = acpi_bus_trim(acpi_device, 1);
-
- if (!result)
- result = acpi_eject_operation(handle, islockable);
-
- if (result) {
- ret = -EBUSY;
- }
+ /* remove the device in another thread to fix the deadlock issue */
+ ret = kernel_thread(acpi_bus_hot_remove_device,
+ acpi_device->handle, SIGCHLD);
err:
return ret;
}