From 26d46867b7d27f68a446b073dac7817721ae4c8f Mon Sep 17 00:00:00 2001 From: Zhang Rui Date: Tue, 29 Apr 2008 02:35:48 -0400 Subject: [PATCH] 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 Signed-off-by: Len Brown Signed-off-by: Andi Kleen --- drivers/acpi/scan.c | 56 ++++++++++++++++++++++++++------------------- 1 file changed, 32 insertions(+), 24 deletions(-) diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 6d85289f1c12..9a84ed250d9f 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include /* for acpi_ex_eisa_id_to_string() */ @@ -92,17 +93,37 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha } 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 @@ static int acpi_eject_operation(acpi_handle handle, int lockable) /* * 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 @@ acpi_eject_store(struct device *d, struct device_attribute *attr, 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; } -- 2.20.1