Commit 708d9893 authored by Syed Nayyar Waris's avatar Syed Nayyar Waris Committed by Jonathan Cameron
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counter: 104-quad-8: Add lock guards - differential encoder 



Add lock protection from race conditions to 104-quad-8 counter driver
for differential encoder status code changes. Mutex lock calls used for
protection.

Signed-off-by: default avatarSyed Nayyar Waris <syednwaris@gmail.com>
Fixes: 954ab5cc ("counter: 104-quad-8: Support Differential Encoder Cable Status")
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 25f02d32

drivers/counter/104-quad-8.c

+15 −3
Original line number Diff line number Diff line
@@ -1274,18 +1274,26 @@ static ssize_t quad8_signal_cable_fault_read(struct counter_device *counter, 
					     struct counter_signal *signal,

					     void *private, char *buf)

{

	const struct quad8_iio *const priv = counter->priv;

	struct quad8_iio *const priv = counter->priv;

	const size_t channel_id = signal->id / 2;

	const bool disabled = !(priv->cable_fault_enable & BIT(channel_id));

	bool disabled;

	unsigned int status;

	unsigned int fault;



	if (disabled)

	mutex_lock(&priv->lock);



	disabled = !(priv->cable_fault_enable & BIT(channel_id));



	if (disabled) {

		mutex_unlock(&priv->lock);

		return -EINVAL;

	}



	/* Logic 0 = cable fault */

	status = inb(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);



	mutex_unlock(&priv->lock);



	/* Mask respective channel and invert logic */

	fault = !(status & BIT(channel_id));
@@ -1317,6 +1325,8 @@ static ssize_t quad8_signal_cable_fault_enable_write( 
	if (ret)

		return ret;



	mutex_lock(&priv->lock);



	if (enable)

		priv->cable_fault_enable |= BIT(channel_id);

	else
@@ -1327,6 +1337,8 @@ static ssize_t quad8_signal_cable_fault_enable_write( 


	outb(cable_fault_enable, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);



	mutex_unlock(&priv->lock);



	return len;

}