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De Francesco" , Terry Bowman , Robert Richter Subject: [PATCH v1 08/20] cxl/region: Rework memregion id allocation and move it to register_region() Date: Tue, 15 Jul 2025 21:11:31 +0200 Message-ID: <20250715191143.1023512-9-rrichter@amd.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250715191143.1023512-1-rrichter@amd.com> References: <20250715191143.1023512-1-rrichter@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: SATLEXMB03.amd.com (10.181.40.144) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MN1PEPF0000F0E0:EE_|DS0PR12MB7560:EE_ X-MS-Office365-Filtering-Correlation-Id: bd7c84f5-e80d-4dd9-1bb6-08ddc3d392aa X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|1800799024|36860700013|376014|82310400026; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?O0AeTtRAD/3ldxCkwEXOz+ageMstrKSrIGjlo4B+fJFNFB6G9JH6eROh/DZY?= =?us-ascii?Q?BkyS7i5MLLVXAAiQF0bAALFQasB2hAkO7JX3IvdgoryTZfpDBSrLwnqR6ZAG?= =?us-ascii?Q?Hy+FQXQEyeK7NIcBkA1n6wNCzD+C3uW5MqST7An1x/LCLC29aM+rRYFPccTe?= =?us-ascii?Q?Npbc3YYwl1Bz8c79Kg/em2wxiP+onVhiA5zgC/nv1LBiJhsHCqxZdjQzdd0m?= =?us-ascii?Q?w6FuhGsLHSKBYD2TsCP5ZTDCH31VgTkHr84OhwjXNCncck1NU7iYbN55R1si?= =?us-ascii?Q?7sux1Vh8j0VkLbJTRKiZaH2bNS1VlCErzmCDM2qRSMwhstfBg62KSxICsy7M?= =?us-ascii?Q?Cx73RLTdtOh2E3bSdXdnnrFf/X/WN2ADRv6lfgXyn5JW/eY0yc37AdV5fL0c?= =?us-ascii?Q?0RqurOoig/75W11m5SNUV91tuj/zWTOKoodWvRlhiBkW8ClWeozN+7tomca+?= =?us-ascii?Q?+6Xqxmc9ShtG5gU15Oa4zHfiFOt8rB03N/ae4rZTuTRrKN/4ZewckoFZCaxv?= =?us-ascii?Q?R1QppXYIStkpvdkF8Dz1y0Re8LQmgfnbUCm8lOaA0vwsn1bM0STJPLRW4+UC?= =?us-ascii?Q?SvcXaEWx5Ei7uJ4lN3UoiC+y0RcKOA1cXIz++TlRFTp9BiWNDTOVHhRCI5CK?= =?us-ascii?Q?ggvXcRRk6mXvyiRERYVkZM+KvrMfAes9iTwF3HOJCmqNZAYrbwb6RrX29jcW?= =?us-ascii?Q?u0UcQ2cBxPgQt11rVrw8NPJCz74w61xF1cvtKIxLO7ooNGdEntr5Uq7eWFy1?= =?us-ascii?Q?oMQDurzYMedknoCfX0aPHMNFpbH2bYQnYxXAvzfuX9oaMjscgdQgVu1kbL7E?= =?us-ascii?Q?67RQnuzIm+kC03ggWgepTenE+mL409bd47yf9HlD4bpB9nIIlHLFsRejobuM?= =?us-ascii?Q?K5R7dq1T8BbfG6VsE5AyZeL2FcMVs+4wkg/45YcuEIdhuroZApOK9VgaIbTY?= =?us-ascii?Q?e1gXLGedPGX2f8mV/fQm/rZFP8PKKaE8TstNYnaH2tR7JGOQtiJIq/nU2tWl?= =?us-ascii?Q?aSnVCyz8LS8FtFYKqg6c9UrjZqp+03uWKtnnQNvuFKUSWB4MSS1YEvryf1vj?= =?us-ascii?Q?zcF+lgCgVq1BAP2hadYpQOL4qXRCFa8ZUgZKRhpdw7YQEIv2WI75jlR6OMi2?= =?us-ascii?Q?qjcjE3TwE8ziSyX6iA+KVTuL7IAimDf8pDbD74kb4l7+I53oo7Gz6NLNUgKT?= =?us-ascii?Q?Qd53BWh9kKxdb9AqoiHptQaBA4tUZ8ANhlEOAPr2Rhhr5gsffiRLbCbUQRjL?= =?us-ascii?Q?sTCMlD+WlMVjW00hFRJeOMBY2Zk48eV/a2WSSkaWTexL3dnVxpTF+I1hZD4F?= =?us-ascii?Q?zvUex+Vwjsw4ZTqgurcsqZ6P0sPyCkeJNFOovLr4b2vn4jlTevht9DdPbzw6?= =?us-ascii?Q?rONdCy2KOXgZPDnOFV+QX/wIgt4QQvpXi+q6wuddA540Xng83ab62L6fES1Y?= =?us-ascii?Q?MWaZ8O7Zu5b9GKs6Wbqq5Oi3gUyKvc5wbxdluqXHqPSicXjpyCoR11A+Wanf?= =?us-ascii?Q?qpJ00ajYKohuV8WiXk4GUuLnoxmxpRht8gT9?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(7416014)(1800799024)(36860700013)(376014)(82310400026);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Jul 2025 19:12:42.2135 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: bd7c84f5-e80d-4dd9-1bb6-08ddc3d392aa X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: MN1PEPF0000F0E0.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB7560 Content-Type: text/plain; charset="utf-8" Make the atomic_cmpxchg() loop an inner loop of register_region(). Simplify calling of __create_region() by modifying the @port_id function argument to accept a value of -1 to indicates that an available memregion id should be assigned to the region. Signed-off-by: Robert Richter --- drivers/cxl/core/region.c | 31 ++++++++++++++++++++++--------- 1 file changed, 22 insertions(+), 9 deletions(-) diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 57ee758bdece..34ffd726859e 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -2504,18 +2504,34 @@ static int register_region(struct cxl_region *cxlr,= int id) { struct cxl_root_decoder *cxlrd =3D cxlr->cxlrd; struct device *dev =3D &cxlr->dev; - int rc; + int old, match, rc; =20 rc =3D memregion_alloc(GFP_KERNEL); if (rc < 0) return rc; =20 - if (atomic_cmpxchg(&cxlrd->region_id, id, rc) !=3D id) { + if (id < 0) + match =3D atomic_read(&cxlrd->region_id); + else + match =3D id; + + for (; match >=3D 0;) { + old =3D atomic_cmpxchg(&cxlrd->region_id, match, rc); + if (old =3D=3D match) + break; + if (id >=3D 0) + break; + match =3D old; + } + + if (match < 0 || match !=3D old) { memregion_free(rc); + if (match < 0) + return -ENXIO; return -EBUSY; } =20 - cxlr->id =3D id; + cxlr->id =3D old; =20 rc =3D dev_set_name(dev, "region%d", cxlr->id); if (rc) @@ -2528,7 +2544,8 @@ static int register_region(struct cxl_region *cxlr, i= nt id) * devm_cxl_add_region - Adds a region to the CXL hierarchy. * @cxlr: region to be added * @id: memregion id to create must match current @port_id of the - * region's @cxlrd + * region's @cxlrd. A negative value indicates that an available + * memregion id should be assigned to the region. * * This is the second step of region initialization. Regions exist within = an * address space which is mapped by a @cxlrd. @@ -3412,11 +3429,7 @@ static struct cxl_region *construct_region(struct cx= l_root_decoder *cxlrd, int rc, part =3D READ_ONCE(cxled->part); struct cxl_region *cxlr; =20 - do { - cxlr =3D __create_region(cxlrd, cxlds->part[part].mode, - atomic_read(&cxlrd->region_id)); - } while (IS_ERR(cxlr) && PTR_ERR(cxlr) =3D=3D -EBUSY); - + cxlr =3D __create_region(cxlrd, cxlds->part[part].mode, -1); if (IS_ERR(cxlr)) { dev_err(cxlmd->dev.parent, "%s:%s: %s failed assign region: %ld\n", --=20 2.39.5