From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1D88F3FD0 for ; Tue, 14 Sep 2021 14:33:28 +0000 (UTC) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-51-GKhXO-hBN5qLmGUxZGUZaQ-1; Tue, 14 Sep 2021 15:33:26 +0100 X-MC-Unique: GKhXO-hBN5qLmGUxZGUZaQ-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.23; Tue, 14 Sep 2021 15:33:24 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.023; Tue, 14 Sep 2021 15:33:24 +0100 From: David Laight To: "'Fabio M. De Francesco'" , Larry Finger , Phillip Potter , "Greg Kroah-Hartman" , "linux-staging@lists.linux.dev" , "linux-kernel@vger.kernel.org" , Michael Straube CC: Pavel Skripkin Subject: RE: [PATCH v4 16/18] staging: r8188eu: hal: Clean up rtw_read*() and rtw_write*() Thread-Topic: [PATCH v4 16/18] staging: r8188eu: hal: Clean up rtw_read*() and rtw_write*() Thread-Index: AQHXqMsDtDyprOASeUiv/PXb20u/Xaujl9CA Date: Tue, 14 Sep 2021 14:33:24 +0000 Message-ID: References: <20210913181002.16651-1-fmdefrancesco@gmail.com> <20210913181002.16651-17-fmdefrancesco@gmail.com> In-Reply-To: <20210913181002.16651-17-fmdefrancesco@gmail.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable From: Fabio M. De Francesco > Sent: 13 September 2021 19:10 ... > +=09u16 address =3D (u16)(addr & 0xffff); >=20 > -=09usbctrl_vendorreq(pintfhdl, wvalue, &data, 1, REALTEK_USB_VENQT_READ)= ; > +=09usbctrl_vendorreq(intfhdl, address, &data, 1, REALTEK_USB_VENQT_READ)= ; You really don't need the (u16) cast or the '& 0xffff'. The assignment will just truncate. But do you even need to truncate the value at all? It rather depends on what happens inside usbctrl_vendorreq() and whether the parameter to this code is already constrained. I think modern gcc are better, but I have seen code where the '& 0xffff' masked the value, then the (u16) masked the value and finally the low 16 bits were written into a structure. (Oh the other patches are now readable - a lot of junk down the pan.) =09David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)