From nobody Sat Feb 7 21:08:13 2026 Received: from DM1PR04CU001.outbound.protection.outlook.com (mail-centralusazon11010022.outbound.protection.outlook.com [52.101.61.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 15D3A331234; Fri, 30 Jan 2026 08:35:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.61.22 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769762156; cv=fail; b=tDH5KMOfXg439i8oUkOv+E8woj1bNGfFR1fnla7TTwJWUffqTU3328mFwbvh2vLiLd4WH7NiJD4WT3pnpeLi/3AMqwZHwNUvRU0Tg2dJ8w3EIl67Qa5tN3DYE2EsvbHNk9imRvhaW3mhqkDdXpiCC+z47nHpVGZnsAFMgzDDKJY= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769762156; c=relaxed/simple; bh=wrgcqL5b1n4zB/KfkM70Ds+rhnEiYU/bfqdsihNEZKg=; h=From:Date:Subject:Content-Type:Message-Id:References:In-Reply-To: To:Cc:MIME-Version; b=Kda/2tNBr4r9cUXf3Jze5TfOulyYp6a47Ltq8DXuNDAIWw/T+xKUfwClOKOwXBnMncn/01bp009Rcd2HnFyNAV9k8c5B9rd6AMR3WsX4MRqJRShaGWufH7ty/C98QB4Z9QWq14yFMiu4if/8XRx4YvRjEFbYXvnAFqZjOR+IEeY= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=q2+cUFzo; arc=fail smtp.client-ip=52.101.61.22 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="q2+cUFzo" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=fTZglbJgh9+M8SR9iHkNKt9dvxh8LBCgf4i17Ouf5I6Z+M8N8w5mWKLMZmHJotKzDQe9cBGBJIH5YaBwsCEgkyuYEhS/UmEq6Yg3IfiIqI6yaOIrSmp1+UEVeEaIi3UOfcrgSqyAGO1IFAIBYLJ6Hx2LkiAjKJlGLdRBUOvPUb7W2lklCbN9lKbotVPEZ/mlGQzLYDgWqWZvT9xqo8r8Lgw3xqWa1FHu6BFfEo3ym1Lh7gE4lMChML6cijleZmUS5RvmT1PqyZJ8Xxz/z7XqbYJlnk1mqahKC2Zv/bl32ZCDAbPCrtaS3zc7OtlPoTtbQTG/mNw44GP3dOTQEDnJyw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=wm7gE6s35eb7zMseO055nM8/YUBt4jNGijgXAN+Np/8=; b=vNChFcDttWi2+ponhvg+A6VrU0NnPxLCeI6Ln4b39t5luKKUDLfHiyF2L+1Mh0Tnpi0D5jfkm4USRChFcMbuf9fR0nP56Ip0WL3h0Q8c9fMtXSDfor2DMeE+Jfzw20ffrkoPei6GWvte6Nv7m5YP1xXpZUKVifYcwX9LLiuqMuADTAcGbMxwvl8P89u78xZE4ZiMt61vAIzWxqecWwiIpWOVH2/I/WUGZFswHqeOuevl62L2/Qe5UNkQSsb66KDSTLj9qVBo6lhGK3tcY6nE5HCyGSpRR1XU+lnO8rtoqL9dtqYUoyZziq4fRSULIf8kKOCLZdbi2KPUDiw/QkCmfA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=wm7gE6s35eb7zMseO055nM8/YUBt4jNGijgXAN+Np/8=; b=q2+cUFzoeu0VYQDSJTNjrYa1dNVTg3OvK0x9KhFQxwFKRGpzsYf1uJlsql4fqECTIVW4pPniJClOku0KTVvL1zMGsgxJN9zeU3Fwao2iJyLZoMTBPUT9996sam0tZbpRbPN1f6mu5OBKYpKzWv7rlnzvBc00K7+nzPba/QsbM3QT5Fiw7UBoZLqA6GRqS1NFuVT+LKdO9yGci63kyUr04+0sBv9dynlm0yT0CcYE7txli36uhnlzOh9KyKCMme6gbWHmQunELe/ef2D3cQXULHF3mjxXbca+708FwTifiCun2XWO2+GYEL9zXBBWyw+EWFwrCCdNqZYfwzkNojnO8w== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from BL0PR12MB2353.namprd12.prod.outlook.com (2603:10b6:207:4c::31) by PH7PR12MB5757.namprd12.prod.outlook.com (2603:10b6:510:1d0::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9564.7; Fri, 30 Jan 2026 08:35:51 +0000 Received: from BL0PR12MB2353.namprd12.prod.outlook.com ([fe80::99b:dcff:8d6d:78e0]) by BL0PR12MB2353.namprd12.prod.outlook.com ([fe80::99b:dcff:8d6d:78e0%6]) with mapi id 15.20.9542.010; Fri, 30 Jan 2026 08:35:51 +0000 From: Eliot Courtney Date: Fri, 30 Jan 2026 17:34:10 +0900 Subject: [PATCH 7/9] rust: dma: implement decay from CoherentArray to CoherentSlice Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260130-coherent-array-v1-7-bcd672dacc70@nvidia.com> References: <20260130-coherent-array-v1-0-bcd672dacc70@nvidia.com> In-Reply-To: <20260130-coherent-array-v1-0-bcd672dacc70@nvidia.com> To: Danilo Krummrich , Alexandre Courbot , Alice Ryhl , David Airlie , Simona Vetter , Abdiel Janulgue , Daniel Almeida , Robin Murphy , Andreas Hindborg , Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Trevor Gross Cc: nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, driver-core@lists.linux.dev, rust-for-linux@vger.kernel.org, Eliot Courtney X-Mailer: b4 0.14.3 X-ClientProxiedBy: TYWP286CA0025.JPNP286.PROD.OUTLOOK.COM (2603:1096:400:262::13) To BL0PR12MB2353.namprd12.prod.outlook.com (2603:10b6:207:4c::31) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL0PR12MB2353:EE_|PH7PR12MB5757:EE_ X-MS-Office365-Filtering-Correlation-Id: a4fa958c-ff2a-4f3b-76c1-08de5fda937d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|366016|10070799003|921020; X-Microsoft-Antispam-Message-Info: =?utf-8?B?ZCs2YkZ1ODhEZlpEV1ZOTnJIbTJLUFN4ZVp4Zi9yQ1BYT0l5TVV0cUFEbmFU?= =?utf-8?B?WjBuYmZYWkQ2ZVNhSFdVRERlMjhUNVZFcnJtWTJLWEE3YmduV2ZGNUZyK2pS?= =?utf-8?B?a3Q2VUdmWTBNWVI2ZFJsSkM2M0dFRUVBQnV0c29DVnBQKzdMNHlMTmpZNlJz?= =?utf-8?B?Z0E0ZHBZRTFGUmdyS1laMlhzY1k2NVRML2M3Y3hjeGJPbS93WEZRK2ZUcHNE?= =?utf-8?B?NnBOTTd2THB2WHk5Z2VmTFJIVExOejgyd0Uxa05uWUttMStWS1FhT2xETkp6?= =?utf-8?B?K1pKYWxHL0x2c0Y0cnpmaTRIbzZqQ0xwWW54bFF0WDcwcVYrcXpoWDBjN0Fh?= =?utf-8?B?ZUJDMGpPa0xKU3ZrUHhISjFyVE9zYW9ncCtLTUp1bHpNNllmQWVzTjFWUWhV?= =?utf-8?B?eUtLRDZMcjR1eHpubzhRTkVrSUhWUGkrSGt1cWIyNlFkazhMZThzQVRsRVBU?= =?utf-8?B?TGwwcVFKdTVNeGRORlpNcW5QOFN4S1BqTHR2L1lZbmNJWDdlMlRzSFp0M2VL?= =?utf-8?B?SXB0QllyTlNrUEh2QW01dUpyQ0I0bmZ4WmI2SHhXNzBteWRQb0V2b1Jtdy95?= =?utf-8?B?UVZTSjlBUGt5Z3oxREZkcVpKQ1JwTWVKUjB0ajA1a1ZUUGMvaUNmeDFnMytO?= =?utf-8?B?QlAwdENKWWZZMnpSS21ZWXVlUlY3MnRNbDM0SEk0QWNSSXZOaUdwZk9uWjd2?= =?utf-8?B?SXpRZ0FFdjVVeXF4YTQ2dW1YTU9CU0dRRVo3LzZ6QnMzczM5NEdKQkp2ck90?= =?utf-8?B?QlNTUnhTYW1mdENpUC9CdVM1Y2V3dlJzTWlEY08xQlhmb0JPaUppUDdqN2Qv?= =?utf-8?B?cmE1NG9TY2tIOVZIalpOUUM0SjJvQXNqSDBuV0gzbVltYnVBYk03R1JHOUhV?= =?utf-8?B?bmptUHQreTZ5QlhJcjRWR3FlWVVianFTVkpjUGZ3SUJlbDNVUFV0V2VzMFVM?= =?utf-8?B?aUYvV0hYaUM4MXJXRnV0dWtaRVJDMmJnU0twOG0xU1NGNDE3eXlXYzdTSU5n?= =?utf-8?B?d3JJQjJweURGTmRiemZxcmt3S09LUXFFNUFuNjBYRjFkU0tvU3BqTW9halJP?= =?utf-8?B?RXJsUmlKZEdoR01OUGJZU1ZwL1BlMS9LdVFlTmc5YlpLTXdFMnNNMVk1SG04?= =?utf-8?B?cEViYjU4NDZhY2VoRTFibVlYcXVnS2oxOFRhSVFQRG14K3NyZmx1U2o2MUF3?= =?utf-8?B?allLQTVTL3FPaCtJOHZrVFhSWnVxcnFtcmxzelFva1FIdUZJODRXd1Z2V2lj?= =?utf-8?B?YzdkaXNSWTRUVTdRZ3NRSHBUakdFRFhmMnZ5L01tdnNhZVEycnllNTVGbFJy?= =?utf-8?B?T2F1d3RqKzZuaXh0amRhVXFURk1HOHpGcGVLcnZQcE1XQnZrdi9DRVNkUVlu?= =?utf-8?B?VytrZzJ2QlBFR2RZNEZDb2o4Z3RsOG1hTHRLOUphYnpKVXlsZzAzbVVDckNl?= =?utf-8?B?MW5nYU12QWVFTDFEUk1PWEwwOUNJQmtxVmhSdjcvMFo2VjV6Q3pKVFBTYVpV?= =?utf-8?B?VDlpMHhKT2RGZGM2NVIyNnd3L1JhQ1ZzckJnQXlab3NteXhTM2g3cUx0TlhY?= =?utf-8?B?S2h3VDZ0UkRQeUgyWTN3L2M1RFJWZ0dDVk5NcXVSZ3JhM3UwRjRwUDZwa05p?= =?utf-8?B?ekFwK3JNY3FSUUIzVDE3Z1k5Y2w5TE55OGEvS0taTXFSQmViV2NONlhrdjZZ?= =?utf-8?B?WDdLQnk5S2xwT1BWYk1Ya3dqUVI3U0I2b21ndDMyQXJXS1JOOXc5cDdkeHI1?= =?utf-8?B?cGVVY0MvY3R0b254WGtJMFZ3bmxQelgvcmVna0dyNUVFN0tuZFlILzVYV2xk?= =?utf-8?B?ZXRSVk5sZGxkRmVQMDNzeEt6dWZNRmsxQVJ2Ky9rWUNCN0lyaWx5ZEFlSUIw?= =?utf-8?B?bm5DQk5UYi9ZQTN4bjE0eU9LbWd4RGFGSTFsbHNTTFVDVjl0M3paWkZzL2Yw?= =?utf-8?B?ODIya2pzNE9rcVh2enQ2bHpmaXFOdDFwOGluYi9DdFZDQ2xCOHVMR3ljcitT?= =?utf-8?B?aDZsamdRbW43UVRKbUkzckFwYi8zelZuOWJSenJnQWJVenhOTDBCdlpJamhh?= =?utf-8?B?dW1Cc050QlRsWjE5THRrVk0zYnhmS051eWtwek5Ka3diTFhzSjdXK3JEcDJn?= =?utf-8?B?WmZBYlZNM1hDc3NQYWVnL2gzZDltSnlabWExSWR6N3RNdFE1UUZtcktNTUFv?= =?utf-8?B?REE9PQ==?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BL0PR12MB2353.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(7416014)(376014)(366016)(10070799003)(921020);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 2 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?WEZiaDFYUHJZaFp2cC9hVGgrQVBqMEplT0xDMzFBZlFGU3pnM0pQV2dab09Y?= =?utf-8?B?S2FwUXhLVWNDMmJMRjdCQ1lpUWJkalYyc21CYXh2QkFFQW9hVjlTVkxvdjFW?= =?utf-8?B?SkcvTE9GOWlzcmtJeTNFdXR0Y2FzNXgxUHhKZVk5MUhwQzNtS29ta0gvWVd2?= =?utf-8?B?bWE4MVkrZEM0c1ZIRk4xSHRDVnpIeTlFc2JONlBGWGkzOGJIdGFlOHFrUnZ4?= =?utf-8?B?RVNiRFFpRG5XaVVoSjUzREthTDhndmJFMHVsbU0rREZXbzVYUjRKNjk2cTl4?= =?utf-8?B?WXNib2FpZElJanBXRGJxWnh5WVJIS2ZJU3JDQ0tOSnFhbzFZUlFEUU8yY0o0?= =?utf-8?B?aWE2a1FQT1RqTHRuRERwcjV3dU5EYmlVMDBac3lkTHUrWklwQkhxUkdpRk5r?= =?utf-8?B?QW5zRitzZWxCS2NCeUt6MEFQMlIzQ0tHUitEN2IzaUNuRjhZMThhNDhaTXZ0?= =?utf-8?B?eU41Y3BSSytvT0M2VEl0WkZwSjlZL2c1K0tMRVJWcnFSdmhGRnZKbyt2aFd6?= =?utf-8?B?Q05pbk91TnZqdUk0cW5OekVGekFsZ3ljWjJwUnlqcFpMTFFQK0JsWkVJZWNu?= =?utf-8?B?QTR1bUs2UXBWVlJKcjl5S1BKcXBnU1lqUnRFR294WlhFN0xpTUEyV2U5V3Z1?= =?utf-8?B?N1hySm1GSzF3Qk1ZdVB2dkVteGdPc1Urb0FrSzB4dzVhZWw5d09MdXgxcDhl?= =?utf-8?B?NHFIUnpQaVNQZXRRMDcxY0JzN1RreEF0YXhaZzZ6bVdneENjUTBmS3lQRnVO?= =?utf-8?B?TGw1RXVGZHN2b0JBRktnVkRWcktCNFZ2NlF5YWJaYTlCaDcyaWs5aCtLVVMr?= =?utf-8?B?T0diNlBsdXBqUDF2VlVJcnREVlhoZnpsVDNwTE1XcDRuN1RKbHU2blo1Snpj?= =?utf-8?B?MDFHczJBcnlOaHkwVVpLQjJQSGVLZEZIc2NNSjdJNHc5SnE2Y05wVy9QMGZo?= =?utf-8?B?bXBpMDFMWFpWUXZscTFuMWUyb2NtZUIwdFRtTHd0SXFzbWo5ZHl3bUhDejEv?= =?utf-8?B?anlnazhNZWd6cWl0clF4VmFoN1JyS090b1pnTlVvM1hIZ3BvLytlSkZNdWtX?= =?utf-8?B?SnM5YmthbnR5TG10OTdzblRxQVc1ejV2UWQ3YmhPZlUrOGR3YTZ6RU9JUFIy?= =?utf-8?B?TjRYbEJUdkwrOVBabnE5SXNIQzZ0ekdPbGFwMGJQeHIxWWJCQ0wxYWZJLzM5?= =?utf-8?B?dVNPUUc5WmgwbTBITnBkN0wxak9sLzNyeFpUU2E5SVdHSzQwbWFZSjRJNWpB?= =?utf-8?B?bWR6cG9rSGFZNzhqeDV4RTNHVkM5WXh0Wk1YY1cxSHNvNEt0RE45eUo4ZE40?= =?utf-8?B?ZEYvcURqN0hKUUFZNEFzSmlQb1d0K0hFZkhoWHlaWmJSN0pSRXFSN2NsS0h2?= =?utf-8?B?R3pNNVROcVpiUGZId3E2OHBmNHJVZWxsQUswUHozQklHa0c1ZkZKbWtnemVS?= =?utf-8?B?S0l3ZUVqSGxpNzA4TldjV2FNcVdIdVNjdVBCM1U2Q2dkdExrcHMvZzBmYzF3?= =?utf-8?B?amgrancrMXJMRlgyOU1WNys5Q2wyd1hhcEdiZndBSi95ZE84RGJ6cnpQUVg3?= =?utf-8?B?T1FQOEEvMDk0QVBVempucEJDL2hLaVlqT00yTWdHUmYxbWgvY05Ld3F0KzZV?= =?utf-8?B?THRZT2lNK1BVYXdiRHZEN3hBYmlIT3dmd3hVZkZ1YTc3N3JaZnhsc0NCbWl3?= =?utf-8?B?NGVHdmRQUjViMzVrWUUxcC9JbDFKcWFaTmZhaE1nZFBXajZIM3U0YlNUckZC?= =?utf-8?B?OFZReWg5RWxObGZ6c0FjRWp1S25kS25qUkx4YTgvZU1zN1V1ZmxIeUFMUXJj?= =?utf-8?B?a2V1cExZS2k2TG8weGJYbFZDeVk3d2Q5a0VKcVFVTStyN0FmMURaQm9sSmN3?= =?utf-8?B?SU03UHBHZVhRdUNtTGpNTUUzd0o2b3ZUcTNWSzRYVzhHVDJYZ3hkNU1VT3Ax?= =?utf-8?B?bWtLNS9XbDBIQ0tyMFBzQ3JDblpFdU50a011Q2k2VWlFTTFsK3J2YitDa1ho?= =?utf-8?B?cTg0czdmNHhIRWRwL2hGczY2MnV3aFJ1WDdTcWVGY1czd2hGSWJ5OWk4cUtv?= =?utf-8?B?UDRZL0NjemNTRE1qUFArTDVRTHZHYkpjT0NLSXFGUmp6aXdBWDQzd1MxMkFh?= =?utf-8?B?alFVaTA4Wi9kOTRKNmRqOTB1WnJia2xSaEQ4N0V6SXp5TjZvMmlqVXRjUjhX?= =?utf-8?B?NzFybXhMVTJ1NC9MM3ViUlJGQ01CMnVxRlVOcCtpQjlOTDNtU1VydkxYZ2Vj?= =?utf-8?B?T0xiOWcrY01kU3hoMm9iUG9Ba3FFaDJ4VHM1ZzgzTmxRMnpWelVmTk9WTmRa?= =?utf-8?B?WkV4c1VweDZDaEk5enlhSXRMbWdmRWxjcG4weW5zQ2t5WUJmS0JvSDJiSnlX?= =?utf-8?Q?CAwnKqoX8SOjT0AmfAB+DYSWVWgRw7sCdmKA/BHmYG4K9?= X-MS-Exchange-AntiSpam-MessageData-1: ExEOlUFlNde2pw== X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: a4fa958c-ff2a-4f3b-76c1-08de5fda937d X-MS-Exchange-CrossTenant-AuthSource: BL0PR12MB2353.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Jan 2026 08:35:51.7381 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: yXksveCiodlzXoBj2RGJpdh4rxFGg8r1QM6QI+hL6IgqKr+d0o7Ir11REaowXd1sDTKcEeRHCq1ClkIEh2Z0Ew== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB5757 Implement Deref, DerefMut, AsRef, AsMut, From for various methods of decaying CoherentArray to CoherentSlice. This is so statically sized CoherentArrays can be used as if they were CoherentSlices by code that doesn't care about knowing the compile time size. This also helps avoid having to annotate static sizes on types all the time. Signed-off-by: Eliot Courtney --- rust/kernel/dma.rs | 48 ++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 46 insertions(+), 2 deletions(-) diff --git a/rust/kernel/dma.rs b/rust/kernel/dma.rs index f3920f74583a..25da678c863b 100644 --- a/rust/kernel/dma.rs +++ b/rust/kernel/dma.rs @@ -12,7 +12,11 @@ sync::aref::ARef, transmute::{AsBytes, FromBytes}, }; -use core::{marker::PhantomData, ptr::NonNull}; +use core::{ + marker::PhantomData, + ops::{Deref, DerefMut}, + ptr::NonNull, // +}; =20 /// DMA address type. /// @@ -389,7 +393,8 @@ impl AllocationSize for StaticSize {} /// # Allocation size /// /// [`CoherentAllocation`] is generic over an [`AllocationSize`], which le= ts it record a compile -/// time known size (in number of elements of `T`). +/// time known size (in number of elements of `T`). A statically sized [`C= oherentAllocation`] can +/// decay to a runtime sized one via deref coercion. // TODO // // DMA allocations potentially carry device resources (e.g.IOMMU mappings)= , hence for soundness @@ -402,6 +407,7 @@ impl AllocationSize for StaticSize {} // // Hence, find a way to revoke the device resources of a `CoherentAllocati= on`, but not the // entire `CoherentAllocation` including the allocated memory itself. +#[repr(C)] pub struct CoherentAllocation { dev: ARef, dma_handle: DmaAddress, @@ -857,6 +863,44 @@ unsafe impl Send { } =20 +impl Deref for CoherentArray= { + type Target =3D CoherentSlice; + + fn deref(&self) -> &Self::Target { + // SAFETY: `CoherentArray` and `CoherentSlice` are both `= CoherentAllocation` + // with different `S: AllocationSize` marker types. Since `Allocat= ionSize` is only stored as + // `PhantomData` (a ZST) and CoherentAllocation is `repr(= C)`, both types have + // identical memory layouts. + unsafe { &*core::ptr::from_ref(self).cast::>() } + } +} + +impl DerefMut for CoherentArray { + fn deref_mut(&mut self) -> &mut Self::Target { + // SAFETY: Same as `Deref::deref`. + unsafe { &mut *core::ptr::from_mut(self).cast::>(= ) } + } +} + +impl AsRef> for C= oherentArray { + fn as_ref(&self) -> &CoherentSlice { + self + } +} + +impl AsMut> for C= oherentArray { + fn as_mut(&mut self) -> &mut CoherentSlice { + self + } +} + +impl From> for= CoherentSlice { + fn from(array: CoherentArray) -> Self { + // SAFETY: Same as `Deref::deref`. + unsafe { core::mem::transmute(array) } + } +} + /// Reads a field of an item from an allocated region of structs. /// /// # Examples --=20 2.52.0