Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 24 Feb 2022 10:53:46 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     Kalle Valo <kvalo@kernel.org>
Cc:     Francesco Magliocca <franciman12@gmail.com>,
        Jeff Johnson <quic_jjohnson@quicinc.com>,
        ath10k@lists.infradead.org, rmanohar@qti.qualcomm.com,
        linux-wireless@vger.kernel.org
Subject: Re: [PATCH v2] ath10k: fix pointer arithmetic error in trace call
Message-ID: <20220224075346.GL3943@kadam>
References: <20220221122638.7971-1-franciman12@gmail.com>
 <e32de43c-e00a-5766-e988-fe192d36d719@quicinc.com>
 <CAH4F6utmtAM3CzX2_Fbn94Sb-X8m0patPh8yWwbuBB0t1VYH=g@mail.gmail.com>
 <87o82wvhtk.fsf@kernel.org>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <87o82wvhtk.fsf@kernel.org>
User-Agent: Mutt/1.9.4 (2018-02-28)
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?JN/5zbgQHkc2Rpewnvuh11CZEH4jPlSuuwM5GjkabkpNFqE21/m0tpzYVjQr?=
 =?us-ascii?Q?R+pdTh7xdO2yJBOV9Jy2d8ADUY4S12ffYXQhnR4gqEmnUe3CtgoC7AxjRXsT?=
 =?us-ascii?Q?kac4WcLgLrDL2JiQsycdf+aICcKLmHcT7JKa4chajowkWv0/57Xfmi8ogzRy?=
 =?us-ascii?Q?AGmlgHoLizhEePJHUUhrZL+Cb/je79kZbCmSYUo5LNJk4RNNTrNw0IbClwpd?=
 =?us-ascii?Q?2lWZJlCZSycSy9nW50gRQ8lQlBNGgh3gMcUvxV+/hL28V24B9qdOtxjbnbt+?=
 =?us-ascii?Q?tcP6VkYOaSPyEGbI7to6EiwUU/391BpmagX1Auv9caax/3i7wQf3YuICEDpE?=
 =?us-ascii?Q?YG5jc67TAwMbBiQwoQkTyJM4zvQ2iq4NJlrFWYwzQF/7nPhZQdVYpiH7TWD+?=
 =?us-ascii?Q?102cE9t41FxCWRCPNNKsgxTsGSZWerj7ioGWIlDM6QfupVL7rtLKe1yV8fXE?=
 =?us-ascii?Q?bUBJkXdJEGU0eeuvReJzDVYWe+x8NkwXpyYMk80lgfxCzaHVRorqXdeFIfQ4?=
 =?us-ascii?Q?R5olh6XfMaLRJ9vCyS9CitflTdAaoh0Arj6SD+Mamxfaj0qeirdnABx/IE6m?=
 =?us-ascii?Q?Jkap2OHppzSAAHnRxFUGLOUgv6KfL8Qm6ce0ygDfnONrEGb0e4aJaZzu+ilR?=
 =?us-ascii?Q?fcqyyjoBPL0Ew22jX5Gzx8mJ0zLC3widUWHHyGky9vzD3tdng/V4N92XWxg8?=
 =?us-ascii?Q?v+mBmcCjfch4Vm8sJpGJHB48SQ76HkO2++BsJ3pDDo7ELdS5G0TR3d3QYFwc?=
 =?us-ascii?Q?ea2bLd8wx7A4vu3uPWyIS2sKJ8E3k2/f9776c8gjPhFEmQMDoX659VHBk5Aw?=
 =?us-ascii?Q?cOIK5qSAWGwHcRIpMrBmvmHQ/up85NS1u0IABdBejITAXK6pbWYkRcwb7PqJ?=
 =?us-ascii?Q?gn+YqU/bYrO3qy/QyCjRS+n/jQ+sqL8zM5IMLCCkjLYtA3C+YqLTdyaIBF5m?=
 =?us-ascii?Q?x84AngpeGWfaWxQYrxEz1c1XV6jslnohmdHRJoaYzTB4jCKvcUXfXFxCMYSp?=
 =?us-ascii?Q?AbmnsfyrhcfPuM1L7aHYtR+3Gzd+m2rqcHdSgWyKflwuAy+XI3qA2w93syzT?=
 =?us-ascii?Q?WVxNlZq9sCNRzLk5AqgUiWQoLFYA9ERHbruUrCfRnLHl5YgSVkeZLeCdeZUA?=
 =?us-ascii?Q?y2NJK0xOeEjvLY1ETxP0tefhOiRrr/LyC3nMtIRD9zOCIsrGK7Fgjqjyy6Iv?=
 =?us-ascii?Q?I9W2jjckEvM/FdJXcuoSh2LTdqatCN+mYVke6n+LsOt2HtoAy/A16K8IPiXP?=
 =?us-ascii?Q?GAvEWs4Tdfwf+vMXmj5qhPIkNPTwdiAx/9XkpZCaHMOqRJutSM1+MyfsT2LF?=
 =?us-ascii?Q?orHpR5zyEaEvZ8ff69aQLYmPp5aC0SsgyEsvOzqwyO6FR4ey2YFestdZ1ZYU?=
 =?us-ascii?Q?k6JdnguZae+Pcbh/fLjKuphAzxG+svDevQvjs8JwPORHGn+51rp6vSynC7qR?=
 =?us-ascii?Q?SQnN91gXZKCiVUygHzW2uLjcopHGJmg45T4MJ2JMsEJcnuyqSbZSAS4Na52D?=
 =?us-ascii?Q?ESkCpLBKHTdsxGQ4DutOICG/Nn5vST13cw+4B7oJVxpW3zeiXQ4QmtU38NeM?=
 =?us-ascii?Q?+ye2svzRG9+b65msrweBtHk6QcjK1HxHqtYpq/eYC8h5O3qBuTL04TSpj6LX?=
 =?us-ascii?Q?wwrXNyWEYXnsDOOXFjcpuOozAltwg2yyhYFSY+zvFDkLi81b8DyVi9UFBNch?=
 =?us-ascii?Q?h54Aig=3D=3D?=
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 11983101-d96a-4cd4-09f2-08d9f76ad2c4
X-MS-Exchange-CrossTenant-AuthSource: MWHPR1001MB2365.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Feb 2022 07:54:02.5698
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: P9E19NA5Wic0L0EmS3GlUOpCZwDDY/xxkT5ByW5H/CfmE4Wg4m9wQiBKQAmMFyttvZ9ZXsZdvy1TdL0rOc8HBngkUoYIdhvigD8aqhf1Vl0=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR10MB4348
X-Proofpoint-Virus-Version: vendor=nai engine=6300 definitions=10267 signatures=681306
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=0 adultscore=0
 malwarescore=0 phishscore=0 mlxlogscore=999 mlxscore=0 bulkscore=0
 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000
 definitions=main-2202240046
X-Proofpoint-GUID: mEmj7nS_IZ4Q11yVDyOyVEl89SJzHeZr
X-Proofpoint-ORIG-GUID: mEmj7nS_IZ4Q11yVDyOyVEl89SJzHeZr
X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW,
        RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,
        T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-wireless.vger.kernel.org>
X-Mailing-List: linux-wireless@vger.kernel.org

On Thu, Feb 24, 2022 at 09:34:31AM +0200, Kalle Valo wrote:
> Francesco Magliocca <franciman12@gmail.com> writes:
> 
> > Hi, I picked (void*) to be conformant with the other examples in htt_rx.c
> > For example at line 1431:
> >>    rxd = HTT_RX_BUF_TO_RX_DESC(hw,
> >>                    (void *)msdu->data - hw->rx_desc_ops->rx_desc_size);
> >
> > But for me it is ok. Maybe we should fix all the occurrences of this kind.
> 
> Yeah, it would be good to fix the void pointer arithmetic in a separate
> patch. I have planning to enable -Wpointer-arith in my ath10k-check and
> ath11k-check scripts, so patches are very welcome.

Void * casts simplify a lot of code.  Less noise.  More readable.
They're more accurate in a sense because it's not a u8 at all.  The
kernel can't compile with other compilers besides GCC and Clang so why
care about that the C standard hasn't caught up?

What does -Wpointer-arith buy us?

regards,
dan carpenter