linux-kernel - usb: mtu3: Checking initialisation of the variable “mep” in two functions

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Message-ID: <8efdb7aa-1188-e94a-3075-ab1dd30768bb@web.de>
Date:   Sat, 27 Jun 2020 14:28:50 +0200
From:   Markus Elfring <Markus.Elfring@....de>
To:     linux-mediatek@...ts.infradead.org, linux-usb@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Chunfeng Yun <chunfeng.yun@...iatek.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Matthias Brugger <matthias.bgg@...il.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org,
        Colin Ian King <colin.king@...onical.com>
Subject: usb: mtu3: Checking initialisation of the variable “mep” in two functions

Hello,

A source code analysis approach by the means of the semantic patch language
(Coccinelle software) pointed an implementation detail out for further
development considerations.

The functions “mtu3_gadget_ep_set_halt” and “mtu3_gadget_ep_set_wedge” check
at the beginning if the input parameter “ep” is a null pointer.
The error code “-EINVAL” will be returned then.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/mtu3/mtu3_gadget.c?id=1590a2e1c681b0991bd42c992cabfd380e0338f2#n371
https://elixir.bootlin.com/linux/v5.7.2/source/drivers/usb/mtu3/mtu3_gadget.c#L371

Can it be nicer to assign the variable “mep” only after a successful check
instead of an initialisation before?

Regards,
Markus