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Commit 794d1756 authored by David Herrmann's avatar David Herrmann Committed by Gustavo Padovan
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Bluetooth: hidp: Stop I/O on shutdown 



Current hidp driver purges the in/out queue on HID shutdown, but does
not prevent further I/O. If a driver uses hidp_output_raw_report or
hidp_get_raw_report during shutdown, the driver hangs for 5 or 10
seconds per call until it gets a timeout.
That is, if the output queue of an HID driver has 10 messages pending,
it will take 50s until hid_destroy_device() will return. The
hidp_session_sem semaphore is held during shutdown so no other HID
device may be added/removed during this time.

This patch makes hidp_output_raw_report and hidp_get_raw_report fail if
session->terminate is true. Also hidp_session will wakeup all current
calls to these functions to cancel the current operations.

We already purge the current I/O queues on hidp_stop(), so this data loss
does not change the behaviour of the HID drivers.

Signed-off-by: default avatarDavid Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: default avatarGustavo F. Padovan <padovan@profusion.mobi>
parent a5fd6f30

net/bluetooth/hidp/core.c

+20 −14
Original line number Diff line number Diff line
@@ -255,6 +255,9 @@ static int __hidp_send_ctrl_message(struct hidp_session *session, 


	BT_DBG("session %p data %p size %d", session, data, size);



	if (atomic_read(&session->terminate))

		return -EIO;



	skb = alloc_skb(size + 1, GFP_ATOMIC);

	if (!skb) {

		BT_ERR("Can't allocate memory for new frame");
@@ -329,6 +332,7 @@ static int hidp_get_raw_report(struct hid_device *hid, 
	struct sk_buff *skb;

	size_t len;

	int numbered_reports = hid->report_enum[report_type].numbered;

	int ret;



	switch (report_type) {

	case HID_FEATURE_REPORT:
@@ -352,8 +356,9 @@ static int hidp_get_raw_report(struct hid_device *hid, 
	session->waiting_report_number = numbered_reports ? report_number : -1;

	set_bit(HIDP_WAITING_FOR_RETURN, &session->flags);

	data[0] = report_number;

	if (hidp_send_ctrl_message(hid->driver_data, report_type, data, 1))

		goto err_eio;

	ret = hidp_send_ctrl_message(hid->driver_data, report_type, data, 1);

	if (ret)

		goto err;



	/* Wait for the return of the report. The returned report

	   gets put in session->report_return.  */
@@ -365,11 +370,13 @@ static int hidp_get_raw_report(struct hid_device *hid, 
			5*HZ);

		if (res == 0) {

			/* timeout */

			goto err_eio;

			ret = -EIO;

			goto err;

		}

		if (res < 0) {

			/* signal */

			goto err_restartsys;

			ret = -ERESTARTSYS;

			goto err;

		}

	}
@@ -390,14 +397,10 @@ static int hidp_get_raw_report(struct hid_device *hid, 


	return len;



err_restartsys:

	clear_bit(HIDP_WAITING_FOR_RETURN, &session->flags);

	mutex_unlock(&session->report_mutex);

	return -ERESTARTSYS;

err_eio:

err:

	clear_bit(HIDP_WAITING_FOR_RETURN, &session->flags);

	mutex_unlock(&session->report_mutex);

	return -EIO;

	return ret;

}



static int hidp_output_raw_report(struct hid_device *hid, unsigned char *data, size_t count,
@@ -422,11 +425,10 @@ static int hidp_output_raw_report(struct hid_device *hid, unsigned char *data, s 


	/* Set up our wait, and send the report request to the device. */

	set_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags);

	if (hidp_send_ctrl_message(hid->driver_data, report_type,

			data, count)) {

		ret = -ENOMEM;

	ret = hidp_send_ctrl_message(hid->driver_data, report_type, data,

									count);

	if (ret)

		goto err;

	}



	/* Wait for the ACK from the device. */

	while (test_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags)) {
@@ -739,6 +741,10 @@ static int hidp_session(void *arg) 
	remove_wait_queue(sk_sleep(intr_sk), &intr_wait);

	remove_wait_queue(sk_sleep(ctrl_sk), &ctrl_wait);



	clear_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags);

	clear_bit(HIDP_WAITING_FOR_RETURN, &session->flags);

	wake_up_interruptible(&session->report_queue);



	down_write(&hidp_session_sem);



	hidp_del_timer(session);