Пример #1
0
ssize_t rtlx_write(int index, const void __user *buffer, size_t count)
{
	struct rtlx_channel *rt;
	unsigned long failed;
	size_t rt_read;
	size_t fl;

	if (rtlx == NULL)
		return(-ENOSYS);

	rt = &rtlx->channel[index];

	mutex_lock(&channel_wqs[index].mutex);
	smp_rmb();
	rt_read = rt->rt_read;

	/* total number of bytes to copy */
	count = min(count, (size_t)write_spacefree(rt_read, rt->rt_write,
							rt->buffer_size));

	/* first bit from write pointer to the end of the buffer, or count */
	fl = min(count, (size_t) rt->buffer_size - rt->rt_write);

	failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl);
	if (failed)
		goto out;

	/* if there's any left copy to the beginning of the buffer */
	if (count - fl) {
		failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
	}

out:
	count -= failed;

	smp_wmb();
	rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
	smp_wmb();
	mutex_unlock(&channel_wqs[index].mutex);

	return count;
}
Пример #2
0
unsigned int rtlx_write_poll(int index)
{
	struct rtlx_channel *chan = &rtlx->channel[index];
	return write_spacefree(chan->rt_read, chan->rt_write, chan->buffer_size);
}