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De Francesco" , Terry Bowman , Robert Richter Subject: [PATCH v4 10/14] cxl/region: Add function to find a port's switch decoder by range Date: Thu, 6 Mar 2025 17:44:44 +0100 Message-ID: <20250306164448.3354845-11-rrichter@amd.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250306164448.3354845-1-rrichter@amd.com> References: <20250306164448.3354845-1-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: SATLEXMB04.amd.com (10.181.40.145) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ1PEPF00001CE8:EE_|DM4PR12MB7551:EE_ X-MS-Office365-Filtering-Correlation-Id: f5c1bb75-67b7-43bb-2efb-08dd5cce5853 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|1800799024|82310400026|7416014|376014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?6NqVdR7yj1D09KxKGGtqSScYJm8fUxI8kspuyybdgIvRLu44bCoRORKhMXSP?= =?us-ascii?Q?i0RMbe1v7Bdq04+9GWjfNczPz8bGTUE/FEOF0xKDUJ+WgjTuX/SX05llnPEN?= =?us-ascii?Q?ot6nX2rWKkAh51xOJQ0aafo0UtjhKFN3VU8/pW/1g/Pg9ou9KX79x1PJTu3I?= =?us-ascii?Q?JW4ChU+h8ldjRKcsX+B1PvA+CvDh1j4ROVlomU48v4n5iZzMXHQUnJxbtLc9?= =?us-ascii?Q?9GlksT1lmpmUXgp/1Elqt8uL+5OUUIfESfyHQyAY+02rUMu87wsbTC5UC5vu?= =?us-ascii?Q?cqFzie3kxL+0uKzJ0hirqFVrrZdqG6ZSH742CaZR6CIUASzH0EMLrJVgIaIr?= =?us-ascii?Q?vYBr4u3p/C/ruD1ZpAlK8zkNOgnpJ82qhBaBG3hCGfsLJshnaHERBmn1+LcT?= =?us-ascii?Q?t7dCUQ0vct3pM0RtRTlaVoMxbE3qpxHsKfkCx0MoYE1j/tg4rZW2RHJQbteP?= =?us-ascii?Q?3ADFAtXJOFyisJNFsoUWRvDY0RjMdp/iE+IKd7q5oXcO1E/2eNc+6Xn8FRVk?= =?us-ascii?Q?4uGVTvbSMGwRapiebyf2Wqw7oxEJagr4NtXf+ik3rGyLqjHjwxSSVvIa8bs8?= =?us-ascii?Q?RYVwdeI1pgpA2nurXB+PmD9PWB4edj+8CXSSjWk6XPhKbGBKtQ8WQaLiywxv?= =?us-ascii?Q?OVxQSY26xqqQZZjpX2mW8uNnS6DAPPVwtmIs7iBwSp8aBQqeoBWkt6CwGLdN?= =?us-ascii?Q?0rOtb/OxWl1e3ypNRgEUCYj1V8Mb/Trscbo9oexSZyX8mVNf1bkknjO7h9Tl?= =?us-ascii?Q?zbDcseZSiuio97bQo/TT98a48LsPhmX04aiHw7GzZ+zA97dn0GTOP/L3e0JU?= =?us-ascii?Q?kCe7Z40o7DuqwCaTw48zJAjSyadjRBS3xze3f+a67zYDZBrecK27iV1iZHSY?= =?us-ascii?Q?i+eQr2OV2YQsRY5rmdPt2Wn91Oo89HGgxvj3+auuuCO8AesJQqVwTiq/Hvww?= =?us-ascii?Q?Dwt1q/4pFGPG9Y25sodRVO7BE0SCklDQGOuRn35ypb4/oIoSX4mTy6iiUewh?= =?us-ascii?Q?xRsgS/PeYhuzwMovne9iH3ykJnL6CBdCfGE1NKtNnHR0p5/rNYw/1nCySEaH?= =?us-ascii?Q?4Z0vmwOiR9N1EAxQWg5cRGxCndlASEhq3Oftj5R68tmodbRrcRGpIbCjvqWF?= =?us-ascii?Q?NnRp1PyPzOsE30psFsrKaXLvnW1KoB7yAgy2C/uhET7AIFWDpHNaCfwi82AK?= =?us-ascii?Q?SHK1Yk35NkMYbLR0fK5fmhsCA9ijJxy/7vxnp2j8rZekveoIzyMolg4sigyU?= =?us-ascii?Q?oL/YGSFcJcnAsFKZICE0FTIFg5NKXo0oSIikBC92y1b4mOeoLTD/PCCtCYtt?= =?us-ascii?Q?gqW45rm0oKYx5kiqURBDSTqdJvUJiTzv0Ok6FbN/Khot9EBvLuBpd6oqcymY?= =?us-ascii?Q?tkkd6TlMmFYlROW3XxM2cU9E0BtWlr7sp6oxAnuE1e4zxJPQdqjquk9x5Xle?= =?us-ascii?Q?FWViZIcx0EX/WDj7Qjl7O/ejM/ksY9C3iwYkjxWTSwg1MF2KC8eLFp/z1/JT?= =?us-ascii?Q?d/o+LFVt4I8Agos=3D?= 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)(36860700013)(1800799024)(82310400026)(7416014)(376014);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Mar 2025 16:45:46.9624 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: f5c1bb75-67b7-43bb-2efb-08dd5cce5853 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: SJ1PEPF00001CE8.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB7551 Content-Type: text/plain; charset="utf-8" Factor out code to find the switch decoder of a port for a specific address range. Reuse the code to search a root decoder, create the function cxl_port_find_switch_decoder() and rework match_root_decoder_by_range() to be usable for switch decoders too. Signed-off-by: Robert Richter Reviewed-by: Gregory Price Reviewed-by: Jonathan Cameron Reviewed-by: Dave Jiang Tested-by: Gregory Price --- drivers/cxl/core/region.c | 48 +++++++++++++++++++++++---------------- 1 file changed, 28 insertions(+), 20 deletions(-) diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 70ff4c94fb7a..cf58ee284696 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -3198,33 +3198,48 @@ static int devm_cxl_add_dax_region(struct cxl_regio= n *cxlr) return rc; } =20 -static int match_root_decoder_by_range(struct device *dev, - const void *data) +static int match_decoder_by_range(struct device *dev, const void *data) { const struct range *r1, *r2 =3D data; - struct cxl_root_decoder *cxlrd; + struct cxl_decoder *cxld; =20 - if (!is_root_decoder(dev)) + if (!is_switch_decoder(dev)) return 0; =20 - cxlrd =3D to_cxl_root_decoder(dev); - r1 =3D &cxlrd->cxlsd.cxld.hpa_range; + cxld =3D to_cxl_decoder(dev); + r1 =3D &cxld->hpa_range; return range_contains(r1, r2); } =20 +static struct cxl_decoder * +cxl_port_find_switch_decoder(struct cxl_port *port, struct range *hpa) +{ + /* + * device_find_child() increments the reference count of the + * the switch decoder's parent port to protect the reference + * to its child. The port is already a parent of the endpoint + * decoder's port, at least indirectly in the port hierarchy. + * Thus, the endpoint already holds a reference for the parent + * port of the switch decoder. Free the unnecessary reference + * here. + */ + struct device *cxld_dev __free(put_device) =3D + device_find_child(&port->dev, hpa, match_decoder_by_range); + + return cxld_dev ? to_cxl_decoder(cxld_dev) : NULL; +} + static struct cxl_root_decoder * cxl_find_root_decoder(struct cxl_endpoint_decoder *cxled) { struct cxl_memdev *cxlmd =3D cxled_to_memdev(cxled); struct cxl_port *port =3D cxled_to_port(cxled); struct cxl_root *cxl_root __free(put_cxl_root) =3D find_cxl_root(port); - struct cxl_decoder *cxld =3D &cxled->cxld; + struct cxl_decoder *root, *cxld =3D &cxled->cxld; struct range *hpa =3D &cxld->hpa_range; - struct device *cxlrd_dev; =20 - cxlrd_dev =3D device_find_child(&cxl_root->port.dev, hpa, - match_root_decoder_by_range); - if (!cxlrd_dev) { + root =3D cxl_port_find_switch_decoder(&cxl_root->port, hpa); + if (!root) { dev_err(cxlmd->dev.parent, "%s:%s no CXL window for range %#llx:%#llx\n", dev_name(&cxlmd->dev), dev_name(&cxld->dev), @@ -3232,16 +3247,9 @@ cxl_find_root_decoder(struct cxl_endpoint_decoder *c= xled) return NULL; } =20 - /* - * device_find_child() created a reference to the root - * decoder. Since the root decoder exists as long as the root - * port exists and the endpoint already holds a reference to - * the root port, this additional reference is not needed. - * Free it here. - */ - put_device(cxlrd_dev); =20 - return to_cxl_root_decoder(cxlrd_dev); + + return to_cxl_root_decoder(&root->dev); } =20 static int match_region_by_range(struct device *dev, const void *data) --=20 2.39.5