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Tue, 25 Aug 2020 14:32:08 +0000 Received: from DM6PR12MB3834.namprd12.prod.outlook.com ([fe80::2d79:7f96:6406:6c76]) by DM6PR12MB3834.namprd12.prod.outlook.com ([fe80::2d79:7f96:6406:6c76%3]) with mapi id 15.20.3305.026; Tue, 25 Aug 2020 14:32:08 +0000 Date: Tue, 25 Aug 2020 11:32:06 -0300 From: Jason Gunthorpe To: Gal Pressman CC: Leon Romanovsky , Doug Ledford , Leon Romanovsky , Adit Ranadive , Ariel Elior , Bernard Metzler , Christian Benvenuti , Dennis Dalessandro , Devesh Sharma , Faisal Latif , Lijun Ou , , Michal Kalderon , "Mike Marciniszyn" , Naresh Kumar PBS , Nelson Escobar , "Parvi Kaustubhi" , Potnuri Bharat Teja , Selvin Xavier , Shiraz Saleem , Somnath Kotur , Sriharsha Basavapatna , VMware PV-Drivers , Weihang Li , "Wei Hu(Xavier)" , Yishai Hadas , Zhu Yanjun Subject: Re: [PATCH rdma-next 01/10] RDMA: Restore ability to fail on PD deallocate Message-ID: <20200825143206.GT1152540@nvidia.com> References: <20200824103247.1088464-1-leon@kernel.org> <20200824103247.1088464-2-leon@kernel.org> <10111f1b-ea06-dce5-a8be-d18e70962547@amazon.com> <20200825115246.GP1152540@nvidia.com> <110cc351-f8f1-8f88-3912-c4dae711b393@amazon.com> <20200825130736.GQ1152540@nvidia.com> <74f893e8-694a-17f0-dc49-05061a214558@amazon.com> <20200825134428.GR1152540@nvidia.com> <5f4f67b1-ca3c-fd11-a835-db7906cad148@amazon.com> Content-Type: text/plain; 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a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1598365830; bh=7A+y8l2gyLnAWM23L/J2w6I/1AKUWc7ubOBnlkuD28I=; h=X-PGP-Universal:ARC-Seal:ARC-Message-Signature: ARC-Authentication-Results:Authentication-Results:Date:From:To:CC: Subject:Message-ID:References:Content-Type:Content-Disposition: In-Reply-To:X-ClientProxiedBy:MIME-Version: X-MS-Exchange-MessageSentRepresentingType:X-Originating-IP: X-MS-PublicTrafficType:X-MS-Office365-Filtering-Correlation-Id: X-MS-TrafficTypeDiagnostic:X-MS-Exchange-Transport-Forked: X-Microsoft-Antispam-PRVS:X-MS-Oob-TLC-OOBClassifiers: X-MS-Exchange-SenderADCheck:X-Microsoft-Antispam: X-Microsoft-Antispam-Message-Info:X-Forefront-Antispam-Report: X-MS-Exchange-AntiSpam-MessageData: X-MS-Exchange-CrossTenant-Network-Message-Id: X-MS-Exchange-CrossTenant-AuthSource: X-MS-Exchange-CrossTenant-AuthAs: X-MS-Exchange-CrossTenant-OriginalArrivalTime: X-MS-Exchange-CrossTenant-FromEntityHeader: X-MS-Exchange-CrossTenant-Id:X-MS-Exchange-CrossTenant-MailboxType: X-MS-Exchange-CrossTenant-UserPrincipalName: X-MS-Exchange-Transport-CrossTenantHeadersStamped:X-OriginatorOrg; b=AXi/x/3WOnf70slJOPGhWFIJ5j5rwWufHxTZOlv8eJ/be84GckXKolP1/MpaBftw6 pC6Nudl7529MJSXdFXgIHU/pwQCWqAbhJLEIZnF2/EARc8YZ9HwbEHtXn7v4orLeHp EWUYgMd/uXUSodGQBWFdULEqZ7ceA3Pabe3XKvq5OE6GUAZw1FzRRQ2i+rcOPBAHKU sdxwpxIJEM2xoNGvU5G8CafZ5Uz0kgMdRDg5M42mbDwPWqT2t0zQMRDAllXFh+d34d zVedIpLeINhBWyg4kY1EwPNU9K5r8IC8YnIQAKuCEcwsau7Ht6F0R4sw1MKjRAc+nB Q4vu5gfpnOz/Q== Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Tue, Aug 25, 2020 at 05:04:14PM +0300, Gal Pressman wrote: > Right, as always, the error code would probably not contain much information, > but there's a big difference between returning error code X/Y vs returning > success instead of an error. To me that just feels wrong, at least in cases > where we can prevent that. >From user perspective it is a success. The purpose of the destroy kernel command is to allow userspace to release the memory underlying the object. The only valid reason to return a failure from destroy to userspace is if userspace has a programming error - eg destroying a PD while QPs exist does fail today for all drivers. Userspace should treat destroy failure as a serious error and crash - there is no possible recovery from it beyond leaking memory. Userspace should NOT be exposed to device failure via destroy. Failed devices trigger an ASYNC EVENT and destroy MUST succeed after the device fatal event. Jason