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Wed, 12 Nov 2025 13:53:09 +0000 Message-ID: <52d862d2-fd26-4770-91ab-9a2ea8073282@amd.com> Date: Wed, 12 Nov 2025 14:53:05 +0100 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 07/20] dma-buf: use inline lock for the dma-fence-array To: phasta@kernel.org, alexdeucher@gmail.com, simona.vetter@ffwll.ch, tursulin@ursulin.net, airlied@gmail.com, felix.kuehling@amd.com, matthew.brost@intel.com Cc: dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org References: <20251031134442.113648-1-christian.koenig@amd.com> <20251031134442.113648-8-christian.koenig@amd.com> <54bdf125bec4dd612d45fc96bb81f03e5a432b02.camel@mailbox.org> Content-Language: en-US From: =?UTF-8?Q?Christian_K=C3=B6nig?= In-Reply-To: <54bdf125bec4dd612d45fc96bb81f03e5a432b02.camel@mailbox.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: FR4P281CA0118.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:bb::9) To PH7PR12MB5685.namprd12.prod.outlook.com (2603:10b6:510:13c::22) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH7PR12MB5685:EE_|PH7PR12MB6490:EE_ X-MS-Office365-Filtering-Correlation-Id: 1a256a46-1b7a-4eaa-2604-08de21f2d009 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|376014; 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To me as a non-expert in dma-buf it's not clear at all > whether this patch here is actually necessary, i.e., solves a problem.  Proof of concept in the sense "I use this patch to test the concept with with the kernel unit tests and robots". > I also don't see how replacing one lock position with another is a > "cleanup". Sharing spinlocks is perfectly legal and will remain so, no? Well that's the more interesting question. On the one hand I'm now pretty sure that allowing those shared fences was a really bad idea, there is simply no valid use case for them. On the other hand changing all the existing implementations would be tons of work with limited gain. I already tried that before and without some intermediate solution like this here it would be an enormous patch set touching all current implementations at the same time. Regards, Christian. > > P. > >