cxacru: Create sysfs attributes in atm_start instead of bind

Since usbatm doesn't set the usb_interface driver data until after calling bind and heavy_init, it would be NULL when the sysfs attributes are read. Reading the MAC address from atm_dev before atm_dev exists would have been be possible too.

Calling create_device_file in atm_start will avoid this problem, and the data is useless until the first status poll runs. However, it must be ready before a status poll does a printk on line status change otherwise userspace could react before the files exist.

For completeness I've moved remove_device_file to atm_stop so it's not called in unbind when it's not needed. There's no point starting ADSL if atm_start could still fail either.

---
This bug find is from the "waiting for my toast to toast" category.

Oops.

drivers/usb/atm/cxacru.c | 45 +++++++++++++++++++++++++--------------------

1 files changed, 25 insertions(+), 20 deletions(-)

index 0b12ace..4ecb4c7 100644
@@ -618,10 +618,22 @@ static int cxacru_card_status(struct cxacru_data *instance)

	return 0;
}

+static void cxacru_remove_device_files(struct usbatm_data *usbatm_instance,
+ struct atm_dev *atm_dev)
+{
+ struct usb_interface *intf = usbatm_instance->usb_intf;
+
+ #define CXACRU_DEVICE_REMOVE_FILE(_name) \
+ device_remove_file(&intf->dev, &dev_attr_##_name);
+ CXACRU_ALL_FILES(REMOVE);
+ #undef CXACRU_DEVICE_REMOVE_FILE
+}
+
static int cxacru_atm_start(struct usbatm_data *usbatm_instance,
struct atm_dev *atm_dev)

{
	struct cxacru_data *instance = usbatm_instance->driver_data;
+	struct usb_interface *intf = usbatm_instance->usb_intf;
	/*
	struct atm_dev *atm_dev = usbatm_instance->atm_dev;
	*/
@@ -638,6 +650,13 @@ static int cxacru_atm_start(struct usbatm_data *usbatm_instance,
		return ret;
	}

+ #define CXACRU_DEVICE_CREATE_FILE(_name) \
+ ret = device_create_file(&intf->dev, &dev_attr_##_name); \
+ if (unlikely(ret)) \
+ goto fail_sysfs;
+ CXACRU_ALL_FILES(CREATE);
+ #undef CXACRU_DEVICE_CREATE_FILE
+

	/* start ADSL */
	mutex_lock(&instance->adsl_state_serialize);
	ret = cxacru_cm(instance, CM_REQUEST_CHIP_ADSL_LINE_START, NULL, 0, NULL, 0);
@@ -669,6 +688,11 @@ static int cxacru_atm_start(struct usbatm_data *usbatm_instance,
	if (start_polling)
		cxacru_poll_status(&instance->poll_work.work);
	return 0;

+
+fail_sysfs:
+ usb_err(usbatm_instance, "cxacru_atm_start: device_create_file failed (%d)\n", ret);
+ cxacru_remove_device_files(usbatm_instance, atm_dev);
+ return ret;
}

static void cxacru_poll_status(struct work_struct *work)
@@ -1054,13 +1078,6 @@ static int cxacru_bind(struct usbatm_data *usbatm_instance,

		goto fail;
	}

- #define CXACRU_DEVICE_CREATE_FILE(_name) \
- ret = device_create_file(&intf->dev, &dev_attr_##_name); \
- if (unlikely(ret)) \
- goto fail_sysfs;
- CXACRU_ALL_FILES(CREATE);
- #undef CXACRU_DEVICE_CREATE_FILE
-

	usb_fill_int_urb(instance->rcv_urb,
			usb_dev, usb_rcvintpipe(usb_dev, CXACRU_EP_CMD),
			instance->rcv_buf, PAGE_SIZE,

@@ -1081,14 +1098,6 @@ static int cxacru_bind(struct usbatm_data *usbatm_instance,

	return 0;

- fail_sysfs:
- dbg("cxacru_bind: device_create_file failed (%d)\n", ret);
-
- #define CXACRU_DEVICE_REMOVE_FILE(_name) \
- device_remove_file(&intf->dev, &dev_attr_##_name);
- CXACRU_ALL_FILES(REMOVE);
- #undef CXACRU_DEVICE_REVOVE_FILE
-
fail:

	free_page((unsigned long) instance->snd_buf);
	free_page((unsigned long) instance->rcv_buf);
@@ -1135,11 +1144,6 @@ static void cxacru_unbind(struct usbatm_data *usbatm_instance,
	free_page((unsigned long) instance->snd_buf);
	free_page((unsigned long) instance->rcv_buf);

- #define CXACRU_DEVICE_REMOVE_FILE(_name) \
- device_remove_file(&intf->dev, &dev_attr_##_name);
- CXACRU_ALL_FILES(REMOVE);
- #undef CXACRU_DEVICE_REVOVE_FILE
-

	kfree(instance);

	usbatm_instance->driver_data = NULL;

@@ -1220,6 +1224,7 @@ static struct usbatm_driver cxacru_driver = {
.heavy_init = cxacru_heavy_init,
.unbind = cxacru_unbind,
.atm_start = cxacru_atm_start,
+ .atm_stop = cxacru_remove_device_files,

	.bulk_in	= CXACRU_EP_DATA,
	.bulk_out	= CXACRU_EP_DATA,
	.rx_padding	= 3,

1.5.0.1

-- 
Simon Arlott