Hi Ilan,
On Tue, Aug 16, 2011 at 2:35 PM, Elias, Ilan <ilane@xxxxxx> wrote:
> +/**
> + * nfc_dev_down - turn off the NFC device
> + *
> + * @dev: The nfc device to be turned off
> + */
> +int nfc_dev_down(struct nfc_dev *dev)
> +{
> + int rc = 0;
> +
> + nfc_dbg("dev_name=%s", dev_name(&dev->dev));
> +
> + device_lock(&dev->dev);
> +
> + if (!device_is_registered(&dev->dev)) {
> + rc = -ENODEV;
> + goto error;
> + }
> +
> + if (!dev->dev_up) {
> + rc = -EINVAL;
> + goto error;
> + }
I think -EALREADY would fit better.
> +
> + if (dev->ops->dev_down)
> + dev->ops->dev_down(dev);
> +
> + dev->dev_up = false;
What happens if the driver is polling for targets or even with a
remote target activated? The nfc_dev structure has some control to
track the driver state (e.g. dev->polling) that must have their values
updated. Otherwise, the next start_poll() call would fail with EBUSY.
> +static int nfc_genl_dev_up(struct sk_buff *skb, struct genl_info *info)
> +{
> + struct nfc_dev *dev;
> + int rc;
> + u32 idx;
> +
> + nfc_dbg("entry");
> +
> + if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
> + return -EINVAL;
> +
> + idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
> +
> + dev = nfc_get_device(idx);
> + if (!dev)
> + return -ENODEV;
> +
> + mutex_lock(&dev->genl_data.genl_data_mutex);
> +
> + rc = nfc_dev_up(dev);
> +
> + mutex_unlock(&dev->genl_data.genl_data_mutex);
This mutex is used to protect the variable dev->genl_data.poll_req_pid
in cases when the netlink socket is closed in parallel with start_poll
or stop_poll calls. As you are not accessing poll_req_pid, you don't
need to care about this mutex.
> +static int nfc_genl_dev_down(struct sk_buff *skb, struct genl_info *info)
> +{
> + struct nfc_dev *dev;
> + int rc;
> + u32 idx;
> +
> + nfc_dbg("entry");
> +
> + if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
> + return -EINVAL;
> +
> + idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
> +
> + dev = nfc_get_device(idx);
> + if (!dev)
> + return -ENODEV;
> +
> + mutex_lock(&dev->genl_data.genl_data_mutex);
> +
> + rc = nfc_dev_down(dev);
> +
> + mutex_unlock(&dev->genl_data.genl_data_mutex);
The same as above.
Regards,
Aloisio
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