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: <bfca2ab7-fbd3-1e7c-3128-c892c519697e@oracle.com>
Date:   Thu, 6 Apr 2023 13:38:30 -0700
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.9.1
Subject: Re: [PATCH] dax: enable dax fault handler to report VM_FAULT_HWPOISON
Content-Language: en-US
To:     Matthew Wilcox <willy@infradead.org>
Cc:     dan.j.williams@intel.com, vishal.l.verma@intel.com,
        dave.jiang@intel.com, ira.weiny@intel.com, viro@zeniv.linux.org.uk,
        brauner@kernel.org, nvdimm@lists.linux.dev,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
References: <20230406175556.452442-1-jane.chu@oracle.com>
 <ZC8eVmF7YdBsDmc4@casper.infradead.org>
From:   Jane Chu <jane.chu@oracle.com>
In-Reply-To: <ZC8eVmF7YdBsDmc4@casper.infradead.org>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?eG41c0s4VE9qR1JMczlLalJIZjQ0YkNtWjJGUVFlR2sxNFY4dHYxdnQ2cGFp?=
 =?utf-8?B?ZnZNQjNKVFkzeXIweDRKTHFhMjNDNWt5ZXVTYTlEa29tVStleVJpWU1HVzdm?=
 =?utf-8?B?eDc1Z1VxYjIxdFZmUHhuL2JudVJ5MTRYUWNHSzIzQVNiWnNCWERPRXRaUTBC?=
 =?utf-8?B?SGhIam9VQzgyWktzUUI4UXhDU0ZUNmg5Z3RwalBwK0hLME43RUdqTmVxM2Ja?=
 =?utf-8?B?dzJ4S3JVbDYvbEwzWktBdXBHM3FNWTFkSWswQTA4RnV5V2lpM0dWUmhpN3Yw?=
 =?utf-8?B?c1Rlb3JhMVowRkY3cTNCTEhZY2lSMFhLcEl5b0hpU3greElIby9JNFAyN3k4?=
 =?utf-8?B?MEl6eTIvVjNwdmg4dlpqaWR0TU1ZZWYvcWxkN0hGOWlIbS8wQ0ozZUM0bEFr?=
 =?utf-8?B?OVJKN1NFbTczeW83Z3dhd0RyNkJ3Qy9mK1Rzc1QvemFDM1NlU1N6RlVrU05u?=
 =?utf-8?B?dGY1QkxXVlkwaUhBM1QyQ09QN214NWJGaHpraWV3a0JCN0xxaEYyWUtwQi9B?=
 =?utf-8?B?SW5wRnpOekJxU2VFUzlldzlJaVcrMk9jOXlwbTd4dnRyTExabldVSzBaTGZD?=
 =?utf-8?B?dk9DdnNQbEhNTjIyb2loQnd2OHhuYVIyNGpQdDJtTk1NU0pDUWhmNmpWRXZY?=
 =?utf-8?B?VG5xVXFUYWdlYkZPam9IWE1HaWdKelA5MlUvOWx6Wmw4dnZ2d2V6cm4vdjFT?=
 =?utf-8?B?MitqNHUybVR4NzZaNVB6MHBwN3B2aUpneG5iVlhqcU9qbHNhdi90M2xKQ2pj?=
 =?utf-8?B?eWc2M0pXTHN1NU1teEtwTCtKVDRFLzFXQnlldU4zRkVIR0hMRXpQbzYzTTFP?=
 =?utf-8?B?V0ZtbGYzY25lZ1FBcFd2SXJXc0d4bXJabC96YjFOaXMwazEwZzZZUDBzdmtR?=
 =?utf-8?B?YjMxakxhaEdxK2dMaDJDeERmZWdReU42QitjcUd6bWtIbXAzWmIvak0vUUdj?=
 =?utf-8?B?RUMwWGw3blh2ZERyRkk2TmgxZmhrL0FpbHpOVlkzU3Y2eTNQNkxBbWY2eVY3?=
 =?utf-8?B?aDhVNTMyNCtLZlp3ekJrTW03WjhUajlYeUdBQmF2MS9yL3RlT2lNN3dKSTdh?=
 =?utf-8?B?SjRTVzRENnU4L1k3Rm9UWHJ0MWNTYTZJL1hzWkJMMytHOUNWMnhoMkN5ZkJm?=
 =?utf-8?B?blFtaVVXZEZkc2FMenB3SVJBMDVkczMzY0piVDREWS9yUFZ2LzlIUUpPVSt0?=
 =?utf-8?B?SFZzbnR4ZDFUU2hEMUxYbUZqR0xhalFKaDgvbko0SjJ0eDN2ZUVnOEhSVUpH?=
 =?utf-8?B?TUVqa2dpSHdxTGY5REVta0lOVDZteG9ndmYyVnZ0elNXZ0pLZ2M4ZUI1b2Jv?=
 =?utf-8?B?UUlnZGM5QmRIUzJKNU5iUUFRNW14cnFwbHc4N25VYk1vVFpNK3NCUkJOYm5k?=
 =?utf-8?B?OXY0TVRhVzdMRUtEZ09pbmt5UnNDWjJNUng5M3dFaUhVOXhjZlJJM1NGdGRS?=
 =?utf-8?B?d1krZU9FWDJjZFAza1I4SlJlY2s2S1VjVE9MbkplQ25wNm9EYUZwVTAxVzFX?=
 =?utf-8?B?RGpia1A0T1l4WnIzdHQwYkpneG81UWs1ZjA2dzh6SnJYc29RZDVGbG9lNDNx?=
 =?utf-8?B?Wm95Z2g2TzFqTWsvNTNBdDF3VGphNURLZ1dYVjFmL2xFdG5jRytpZkpCS1Bv?=
 =?utf-8?B?UVc2aUY3ZjBNVGZDQjBqOWhLdGdxcURONWJ1R1VBUTBzZmlxUWovekpCQ3Zj?=
 =?utf-8?B?TGtGa3BEMGlZWlFWY0lSUmJDYzg4bjk4cEFuemE2TTJPeTlLYmorMCtCUitC?=
 =?utf-8?B?elpTMXhlYkdDbVpBNTNCRjVsVkxqSkVEeUMwVC9pa3B3aFlScCtUNW5MUEc3?=
 =?utf-8?B?M0RsMnhFeEZTd08yVHpmbHlyOFVEWGJDeXBTZlFOaVJIN3A5V05IZGI3TVBH?=
 =?utf-8?B?YVVHeGlkY3JWTlI1Z2VsZVFjVDNDMDdXYXUvUEVPVEFaKzJkcFNreEF3RkNn?=
 =?utf-8?B?Mk9FSU9JcnJvOWpUNjNWbkkwaEIyZDZkdWFQT0ora1d5NWRPUHI1MU9OdE9N?=
 =?utf-8?B?SWJZcTJoN2N4MEdaME5tZFVhZy9MMHJIY21lK1RqbFJCMm1SWEd3YWcrcS9z?=
 =?utf-8?B?VlVyOUxUQkR3TDdiL3BBQlRPQmxiNDExVWRYeVJpVjMxaUpURERyMDREZzN4?=
 =?utf-8?Q?hIUnlrpeirsYcGW8vksshh4cx?=
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: =?utf-8?B?RkVaTko3OWRvVmtKTGp5ZTNVMkdaUlJPUVlMbElpdmZxczd2cWovSlZQVlZX?=
 =?utf-8?B?WHhYSFF1N0RqZGVwKzAwcVNRQmtoNDhjK0tiZ2lIUm1RdWo4YkZpTkdhZndv?=
 =?utf-8?B?YVlCbGxiSDZ3MVEwN2VrV1VKMmNDeGUwZXRTaVZ6VUZUeFZ0dFdObDBBUGE1?=
 =?utf-8?B?WmxtRlVxanhYUlg1ZmErbW1hREFFR1IwbDZDUXhCNVRJMjJiODlmYlFKdi9E?=
 =?utf-8?B?OHViNGM0OW9pNnFUUVdTYVU1aXQ0MXJQSUR2diszT08ra0haeGZydndMNlN0?=
 =?utf-8?B?UDJHMWxHdEtCc09JK3JFZ3BnVVpNQ254eWpTR21NWFkyL2hDNCtVWFBqdDBH?=
 =?utf-8?B?cUZBMndDRkljRWFxYjN2WWhVSHk1WUpDbkxaNjhOQkpkTytUaE0vc05iVWdX?=
 =?utf-8?B?VFdpcjZBVS82aUQyaGVSUFl3U2pUbml6c0h2b252Sk1KaWxvb205QStGb05L?=
 =?utf-8?B?elBXZkdFRi9iM0ovZmx3Y3ZHUHRYejJ0aGwvRHVtUG05bDFPbEw5STR1eDlR?=
 =?utf-8?B?Q09tT252Yzh0SXZjWTJsTHV4YzVXUUgxc01PU096RUZrRUQ3S29GeVFRQkZY?=
 =?utf-8?B?TDY2bFRXa2tFVTVXNm5mT05Cd2FGYm8ySndDckJmVzJBaHlwdnRjUnJ4VGFK?=
 =?utf-8?B?VUQ3MlMvNUVVbzBHSTdHTTZRNU83VHpyWE9tRlNvVUd2ck1QQWx0a2RpN0Ny?=
 =?utf-8?B?UU9iTFRpb0tJdkdUbTZ0UWNaeVV3cEEyR3VPMVd2Q3dSK2Z3bVpSUHBhQmVo?=
 =?utf-8?B?czFvbXM1bUE0dHNMUm1OczFBb1pSM05lSzBBaXkrMDFla2IwK2ZoYk1jUHI3?=
 =?utf-8?B?U2dmai93V1dETk5UZkRsMnlmRE5GOWhTUzJIOVFkbkFwZ2ZIMFF6T2tLZlpU?=
 =?utf-8?B?UlV1djh1SEtLYVVIaXh2RU9jbDNZaUNyMFVLZ3ZZRERudDJCTStsTTdhUWRT?=
 =?utf-8?B?OVc0NHRkeEp6VWRha0Qzem9JcVBFOVpJQUpWenh0ai9XV0pITmJQWmpYRzN5?=
 =?utf-8?B?cDNsZGFNK0NFaDFVNHd3Z2ovNnhJeVNkSTRtd1F4ZEQzWmVmTkJIZ2hZMXFX?=
 =?utf-8?B?SHR4aHkxV2FTbFNkc2lXR0RyaThuL2gxckU5eUJrWFY2UTJIbHJ0SW4zQ0Q3?=
 =?utf-8?B?Mys1SENXbTFUR1QyK0Rvam1ub21iLzI2enZxSGtLL1Q4T2REU3dqcS9ab3l0?=
 =?utf-8?B?NC9aYmw5b1o3S3dlVlR6QmVJWDN1QzlIY09QK2ZPUTVkRmFyUTFqTzNGeU5E?=
 =?utf-8?Q?HNZymQNuAj/Pvvd?=
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 4c3048ac-030a-4ef4-5cad-08db36dee3b1
X-MS-Exchange-CrossTenant-AuthSource: SJ0PR10MB4429.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Apr 2023 20:38:33.6488
 (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: MyNnO/SYBUKM6Jwtzo7vFFYyVQzC2axDR0lBd94jIcaFev2vllpqcW4EDMeHkYrgmWYRuwc3Bwb9UafgGVpsYQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR10MB5776
X-Proofpoint-Virus-Version: vendor=baseguard
 engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22
 definitions=2023-04-06_12,2023-04-06_03,2023-02-09_01
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 suspectscore=0
 mlxlogscore=959 bulkscore=0 malwarescore=0 mlxscore=0 spamscore=0
 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1
 engine=8.12.0-2303200000 definitions=main-2304060183
X-Proofpoint-ORIG-GUID: gWE-c6xDTvR2ksumHpIp8HXxlLzQ0WbG
X-Proofpoint-GUID: gWE-c6xDTvR2ksumHpIp8HXxlLzQ0WbG
X-Spam-Status: No, score=-3.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID,
        DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,RCVD_IN_DNSWL_LOW,
        RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE autolearn=unavailable
        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 4/6/2023 12:32 PM, Matthew Wilcox wrote:
> On Thu, Apr 06, 2023 at 11:55:56AM -0600, Jane Chu wrote:
>>   static vm_fault_t dax_fault_return(int error)
>>   {
>>   	if (error == 0)
>>   		return VM_FAULT_NOPAGE;
>> -	return vmf_error(error);
>> +	else if (error == -ENOMEM)
>> +		return VM_FAULT_OOM;
>> +	else if (error == -EHWPOISON)
>> +		return VM_FAULT_HWPOISON;
>> +	return VM_FAULT_SIGBUS;
>>   }
> 
> Why would we want to handle it here instead of changing vmf_error()?

I think it's related to the comment about the the corrupted range of
a hwpoison caused fault - something no need to worry about now.

I will move the change to vmf_error() in a respin.

Thanks!
-jane