On Wed, Sep 23, 2015 at 01:54:59PM -0400, cpaul@xxxxxxxxxx wrote:
> +static int userio_device_write(struct serio *id, unsigned char val)
> +{
> + struct userio_device *userio = id->port_data;
> + unsigned long flags;
> +
> + if (!userio)
> + return -1;
I still have the same question: how can this happen? Where do we reset
port data to NULL? What happens if we set to NULL after checking?
> +
> + spin_lock_irqsave(&userio->buf_lock, flags);
> +
> + userio->buf[userio->head] = val;
> + userio->head = (userio->head + 1) % USERIO_BUFSIZE;
> +
> + if (userio->head == userio->tail)
> + dev_warn(userio_misc.this_device,
> + "Buffer overflowed, userio client isn't keeping up");
> +
> + spin_unlock_irqrestore(&userio->buf_lock, flags);
> +
> + wake_up_interruptible(&userio->waitq);
> +
> + return 0;
> +}
Thanks.
--
Dmitry
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