Re: [PATCH 13/30] staging: nvec: Rewrite the interrupt handler

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On Fri, Sep 23, 2011 at 06:38:05PM +0200, Julian Andres Klode wrote:
> +struct nvec_msg *nvec_write_sync(struct nvec_chip *nvec,
> +		const unsigned char *data, short size)
> +{
> +	mutex_lock(&nvec->sync_write_mutex);
> +
> +	nvec->sync_write_pending = (data[1] << 8) + data[0];
> +	nvec_write_async(nvec, data, size);
> +
> +	dev_dbg(nvec->dev, "nvec_sync_write: 0x%04x\n",
> +					nvec->sync_write_pending);
> +	if (!(wait_for_completion_timeout(&nvec->sync_write,
> +				msecs_to_jiffies(2000)))) {
> +		dev_warn(nvec->dev, "timeout waiting for sync write to complete\n");
> +		mutex_unlock(&nvec->sync_write_mutex);
> +		return NULL;
> +	}
> +
> +	dev_dbg(nvec->dev, "nvec_sync_write: pong!\n");
> +
> +	mutex_unlock(&nvec->sync_write_mutex);
> +
> +	return nvec->last_sync_msg;

The ->sync_write_mutex protects the ->last_sync_msg member but you're
using it outside the lock here.  (Save a local of msg pointer before
you release the lock).

> +}
> +EXPORT_SYMBOL(nvec_write_sync);

> +
> +/* TX worker */
>  static void nvec_request_master(struct work_struct *work)
>  {
>  	struct nvec_chip *nvec = container_of(work, struct nvec_chip, tx_work);
> +	unsigned long flags;
> +	struct nvec_msg *msg;
>  
> -	if (!list_empty(&nvec->tx_data))
> -		gpio_set_value(nvec->gpio, 0);
> +	spin_lock_irqsave(&nvec->tx_lock, flags);
> +	while (!list_empty(&nvec->tx_data)) {
> +		msg = list_first_entry(&nvec->tx_data, struct nvec_msg, node);
> +		spin_unlock_irqrestore(&nvec->tx_lock, flags);
> +		nvec_gpio_set_value(nvec, 0);
> +		if (!(wait_for_completion_interruptible_timeout(
> +		      &nvec->ec_transfer, msecs_to_jiffies(5000)))) {
> +			dev_warn(nvec->dev, "timeout waiting for ec transfer\n");
> +			nvec_gpio_set_value(nvec, 1);
> +			msg->pos = 0;
> +		} else {
> +			list_del_init(&msg->node);
> +			nvec_msg_free(nvec, msg);

wait_for_completion_interruptible_timeout() returns a negative error
code if it gets interrupted so that case should be handled as well.

regards,
dan carpenter


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