Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <7a689b6c-31b7-61d2-7bf4-6fdf49bb4ae4@vivo.com>
Date:   Fri, 10 Jun 2022 15:52:39 +0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
 Thunderbird/91.7.0
Subject: Re: [PATCH] dma-buf: Don't use typeof in va_arg
Content-Language: en-US
To:     =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org
References: <20220610072019.3075023-1-wanjiabing@vivo.com>
 <c079243c-9084-b565-2320-20453815c79a@amd.com>
From:   Jiabing Wan <wanjiabing@vivo.com>
Organization: vivo
In-Reply-To: <c079243c-9084-b565-2320-20453815c79a@amd.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?V3JITEFlZGg2bG9VL3l6RXFUVDRKQ2VCTmt0T0VpQy9OS1gzai9QQTBKdEIz?=
 =?utf-8?B?bkl4RnZ2aFpYKzczREtzbStOTnUyWnRWemdoK0xtM0dsUzVvN3ptMFRvYzRh?=
 =?utf-8?B?Y1J3djMwb09lNzlUUXZlNDQ5MlRiTDFTZmRzQy8vRC93Y05uemhvdStMcVlz?=
 =?utf-8?B?VjVJU3NNNWc4MXlFNVBlVE1NK0w2OGg3ZnRiZUhxY3ZJTVdoMjZlTEJ1STgr?=
 =?utf-8?B?a3RxeEJVQ0JtVndkNW5lN20wVUFGRmwwVCtkTHBZSmFTM1ZBMTk5d25sb0Ri?=
 =?utf-8?B?RWZ3ekZMK3U2N1lVbEdHWVR5bHo0SkZnUWltM3Y4ZVJuSEt3bnVNMXlxZ3hC?=
 =?utf-8?B?MXl6VDBkL2NobmVyMVMxZFFvbzFhWkVaL0ZPK0VNNEdDMURDU0podit4eFBr?=
 =?utf-8?B?RWxaQUd4dnRKUnEyV3lHU0orVWEyVmhIOWllMjNnekZ4NFpmWTNPc2JHTkdn?=
 =?utf-8?B?UFRLTkIxT3ZhbVYrQXdmWEJxRzR0K0F2T3MzeXIvWHJUKytsWDZWZm41a0NG?=
 =?utf-8?B?NGptOXplQlJZT1cyMUdzU3FjSDduanNabUZmNVdCNlBiTENyYjhIOXc4S3BJ?=
 =?utf-8?B?TTdvRVRnSERDbkorTVc4ZXM1cjVrMXNqOFp5cW1OMjhweXk3R1N0L1hSWDJr?=
 =?utf-8?B?RDlsV0plSjE1enBIZTFhOThEQS80cVNGOGZGWllXbnhjOXI1TEtVSnFTL0Zz?=
 =?utf-8?B?MXdjUVpFd01zejhxcURsUEI5KzZ3MXJaa2IyS0RORURWOCtBUkFlWWpoM0tt?=
 =?utf-8?B?aW03dDhIbGVMMHo5RE5yS0p1UlIxK0xoSkFYOW5ETnZkdE1wWitkeWJSTXZC?=
 =?utf-8?B?d05qOGpIYXpHU0VNRTRKUWpDS0RNK2NFN3ZnUGVveVRJMjg2Ky9BSWZOUG1I?=
 =?utf-8?B?cW9aQmNTT1JGY0szQUNwdGhOZGM1N3ZPalJsUWhzZGtVOTMrS1B0SElLbGNu?=
 =?utf-8?B?MW1Vakg1dXhNTE93R29FNHlGeHpZMGk1TU1haFVZUXJMSWdzdHpwdU9pa1k1?=
 =?utf-8?B?a1FVTEVNUVIwZThyakJTTjZhVFduRkxsUWdFY3pBRlhWK1B3NVJIeWFSalhz?=
 =?utf-8?B?VW9UTDdnNTJBbGkyUzd1d1hGM25jTzd3M3U5ZGV0ODlJWW8rREZZR1VVZlIz?=
 =?utf-8?B?QjFZRWtnV1JtUFZkTzYwNGRYdGdQcE4xK0pQdmFKek9WSGlzeVZQZ3laS21x?=
 =?utf-8?B?bUZRajVGQ0plTWlDclhNb2pDMExnbi9GOXJwaUNVQndlaTFuZGt1R1FVbzZp?=
 =?utf-8?B?T2R3cmxVL01UL3phRngrUlJxL3JteVZ0Y0swdm1kamVqZmk1U1dDNmJ1S0hD?=
 =?utf-8?B?cGt3b2ovVFZrQTMrK3NNWlFkZTRDWHV1NzJHRWVmakpiT1B2TUpMd1JXS0dN?=
 =?utf-8?B?R29lWG01bEN0b1ZwejBCR09ueUlPNHM0Q3lrRnFPTjhYUXlVVW9vaEVUdjNC?=
 =?utf-8?B?TXJNbUhNZE40ZG1kSnlpZmNWaUp5NFRPaStVM3BrV3UwcjZyY1NEd1ZUM2lG?=
 =?utf-8?B?UzFzcjJrNEtpR1YwRXAzWTdZSjYrYk5vd1FjcHhtZW9ZQkdNK0g3cW9xamRB?=
 =?utf-8?B?eDVqd0hPV2tuT0ptWVpsWmlvNVlZN09GK0FJbFROQjNGY3FGUG5KOFcyMk0w?=
 =?utf-8?B?UW1CMkNXNituVjN2cmFxdndhUzlwOFZpZVB1WDN0R2VIRm1hVjZiSmZkdWp0?=
 =?utf-8?B?TmZtU3pYWGtiazdtV3BSYTBxa2hENWFXV1pBekVNaHVxNXY0VFZSVmlFSU1X?=
 =?utf-8?B?WGtaRXJjaGlhejUzN09uSldXdnZ4SVhkN29FRzRQVTBPZXA1Nkt1T1A4ajlt?=
 =?utf-8?B?Q0NtaHluRTVRRHoxSjQ3ck5hV0R5MWM5cFlTZkxsSDUvK3BMNERuR05KT1dw?=
 =?utf-8?B?cjFjZ0x5ZVoyVHBwWW0xRXpPRy94ekgveVRLWi9MSzRLM1RGeFBTa3hjak5p?=
 =?utf-8?B?cHlleWltZ09sU2huYW1JYkIvcXEvSnFadElJMkp0YVIzMVhnSTdZM3hFVzBv?=
 =?utf-8?B?OHNVcWE0WFZjZGJIMkdJeWFXQXNGUFlrVE1JbTE5OGhUWHZiWDdNOEVWWXE3?=
 =?utf-8?B?TVpGTWJ3MTNpOHdyVGpvNU55d3pUeUdDQnlaZnBrM0lCQjNKNTNVVi82N2VD?=
 =?utf-8?B?M0FvVjVmVlVncmZqTnl0bVhwNitTN2MrVEFnNElEQUlSS2hZSmZZdWg5WlBV?=
 =?utf-8?B?U2JqVU54RmVCV3VNVEx3YThsL3kxZmRGYm4xM1Noa2YxK0ZDV0lxUWJBUWlS?=
 =?utf-8?B?VHRKVXZUL1JRUmpvbWxvdjVSVHY1SXBkdVBvVzY5NXQ4V3g0ZWRQRHF1ejJi?=
 =?utf-8?B?bEw3VUpSeFFFeHpOVFM3Rll1R3ZaVGZ4WGIxS1FoSEY2NG1XWmthUT09?=
X-OriginatorOrg: vivo.com
X-MS-Exchange-CrossTenant-Network-Message-Id: f30d2bf0-464e-4186-6fcf-08da4ab63635
X-MS-Exchange-CrossTenant-AuthSource: SG2PR06MB3367.apcprd06.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Jun 2022 07:52:48.2665
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 923e42dc-48d5-4cbe-b582-1a797a6412ed
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: uN1Mhff/SJ13m9dHkLnDnoCiuIJv8dCTCycrihbWROPmr1F752SQrILwssUEQ+uRUfv0NYVG1uM8y9ba1Ccy+Q==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PS1PR0601MB3689
X-Spam-Status: No, score=-3.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,NICE_REPLY_A,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,
        SPF_HELO_PASS,SPF_PASS,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-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


On 2022/6/10 15:24, Christian König wrote:
> Am 10.06.22 um 09:20 schrieb Wan Jiabing:
>> Fix following coccicheck warning:
>> ./drivers/dma-buf/st-dma-fence-unwrap.c:75:39-45: ERROR: reference 
>> preceded by free on line 70
>>
>> Use 'struct dma_fence *' instead of 'typeof(*fences)' to avoid this
>> warning and also fix other 'typeof(*fences)' to make them consistent.
>
> Well that doesn't looks correct to me.
>
> *fence should be valid at this point, why does coccicheck things it is 
> freed?

*fence is valid. Coccicheck reports this because fence is freed.
But use 'struct dma_fence *' can avoid this wrong report.

I also grep all code and find it's unusual to use 'typeof' in va_arg, 
only two files.

grep -R "va_arg("  . | grep 'typeof'
./drivers/dma-buf/st-dma-fence-unwrap.c:                fences[i] = 
va_arg(valist, typeof(*fences));
./drivers/dma-buf/st-dma-fence-unwrap.c: dma_fence_put(va_arg(valist, 
typeof(*fences)));
./lib/test_scanf.c:             typeof(*expect) got = *va_arg(ap, 
typeof(expect));              \

And other files all use declaration name directly.
So I send this patch makes code clearer and fix the wrong warning by the 
way.

Thanks,
Wan Jiabing

>
> Regards,
> Christian.
>
>>
>> Fixes: 0c5064fa8d5a ("dma-buf: cleanup dma_fence_unwrap selftest v2")
>> Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
>> ---
>>   drivers/dma-buf/st-dma-fence-unwrap.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/dma-buf/st-dma-fence-unwrap.c 
>> b/drivers/dma-buf/st-dma-fence-unwrap.c
>> index 4105d5ea8dde..1137a6d90b32 100644
>> --- a/drivers/dma-buf/st-dma-fence-unwrap.c
>> +++ b/drivers/dma-buf/st-dma-fence-unwrap.c
>> @@ -56,7 +56,7 @@ static struct dma_fence *mock_array(unsigned int 
>> num_fences, ...)
>>         va_start(valist, num_fences);
>>       for (i = 0; i < num_fences; ++i)
>> -        fences[i] = va_arg(valist, typeof(*fences));
>> +        fences[i] = va_arg(valist, struct dma_fence *);
>>       va_end(valist);
>>         array = dma_fence_array_create(num_fences, fences,
>> @@ -72,7 +72,7 @@ static struct dma_fence *mock_array(unsigned int 
>> num_fences, ...)
>>   error_put:
>>       va_start(valist, num_fences);
>>       for (i = 0; i < num_fences; ++i)
>> -        dma_fence_put(va_arg(valist, typeof(*fences)));
>> +        dma_fence_put(va_arg(valist, struct dma_fence *));
>>       va_end(valist);
>>       return NULL;
>>   }
>