Re: [patch 14/17] usb: add usb_dev_reset_delayed

ext [email protected] wrote:

> +
> +/*
> + * We need to lock the device before resetting, but we may already have the
> + * lock. So we try to lock the device, if it fails (returns < 0) then we
> + * cannot proceed. If it returned 1 then we acquired the lock here and need
> + * to release the lock. If it returned 0 then we already have the lock and
> + * we leave it to the piece that acquired the lock to release it.
> + */
> +static
> +void usb_dev_reset_delayed_task(struct work_struct *ws)
> +{
> +	struct usb_dev_reset_ctx *reset_ctx =
> +		container_of(ws, struct usb_dev_reset_ctx, ws);
> +	struct usb_device *usb_dev = reset_ctx->usb_dev;
> +	struct device *dev = &usb_dev->dev;
> +	int had_to_lock;
> +	int result = 0;
> +
> +	if (usb_dev == NULL) {
> +		WARN_ON(1);
> +		goto release;
> +	}
> +	had_to_lock = usb_lock_device_for_reset(usb_dev, NULL);
> +	if (had_to_lock < 0) {
> +		if (had_to_lock != -ENODEV)	// ignore dissapearance
Comment with "//" above ...
> +			dev_err(dev, "Cannot lock device for reset: %d\n",
> +				had_to_lock);
> +	} else {
> +		result = usb_reset_device(usb_dev);
> +		if (result < 0 && result != -ENODEV)
> +			dev_err(dev, "Unable to reset device: %d\n", result);
> +		if (had_to_lock)
> +			usb_unlock_device(usb_dev);
> +	}
> +	usb_dev->delayed_reset = 0;
> +	usb_put_dev(usb_dev);
> +release:
> +	kfree(reset_ctx);
> +	module_put(THIS_MODULE);
> +}
> +
> +

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