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From:   "Ahmed S. Darwish" <a.darwish@linutronix.de>
To:     Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Cc:     Felipe Balbi <balbi@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, Peter Chen <peter.chen@nxp.com>,
        Lee Jones <lee.jones@linaro.org>,
        Alan Stern <stern@rowland.harvard.edu>,
        Dejin Zheng <zhengdejin5@gmail.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Michal Nazarewicz <mina86@mina86.com>, stable@vger.kernel.org
Subject: Re: [PATCH v2] usb: udc: core: Use lock when write to soft_connect
Message-ID: <X//nfLN9bW1K/yVm@lx-t490>
References: <311bc6d30b23427420133602c2833308310b7fcb.1610595364.git.Thinh.Nguyen@synopsys.com>
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On Wed, Jan 13, 2021 at 07:38:28PM -0800, Thinh Nguyen wrote:
...
> @@ -1543,10 +1546,12 @@ static ssize_t soft_connect_store(struct device *dev,
>  		usb_gadget_udc_stop(udc);
>  	} else {
>  		dev_err(dev, "unsupported command '%s'\n", buf);
> -		return -EINVAL;
> +		ret = -EINVAL;
>  	}
>
> -	return n;
> +out:
> +	mutex_unlock(&udc_lock);
> +	return ret;
>  }

This is *very* tricky: the return value will be easily broken if someone
adds any code later after the else body and before the "out" label.