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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?vSbmDpeTxfoiMAeGUnBYNKExTgikhpLes5sbuGe7yXy5c6W773E2zo++X3D4?= =?us-ascii?Q?uKLVqMwqPxNUE2TX0GYZ6940VPn5JKeTHJG1Ydth19Nv5BwsUySCm5MyNu6D?= =?us-ascii?Q?QGxhL2ZhCeI09iOlejEBwLvUKkwLrL2QnN5z/qGOHG4yQnI4iRFlX1X8PcaL?= =?us-ascii?Q?bNxkDR2QVq8YbFqMZThILcDoTh3lOWn4x6TFqZXmEZuFuircKxViWOZ7wEDb?= =?us-ascii?Q?ahmbjQhCrwrVdenn/3U+kB5XTO9OW/bb77RpRs8wo++n/rmyIoDK0zN8VR/f?= =?us-ascii?Q?r7JsgFS6Y6QeNWv8MBfwf3w74TeWMuRy90E3tWW5+O8yNHZQAYGKBB8icK7G?= =?us-ascii?Q?HCUuv/gbNbF4GJvxM0N9jRXrQ22yYpmKOrM6rDlWAXaspPxpSuhhW+7gs1No?= =?us-ascii?Q?6l/dnLutNNkNVzzpgXo3lEqcpTcmYDl9q1PI0kovMBCkZ3UHEjDKUhrh4f9K?= =?us-ascii?Q?hbziX93twd+1lx6rgVZqM74NMZ8n2mb2nWkdlwsSr0DPMdNkv8/uYCHCsVC8?= =?us-ascii?Q?vtyZ3mxI17K3tcr270KyuSHzM6ZFZ0GLkXcKqkjdFJQJp0FdD5hkBDL+cXlv?= =?us-ascii?Q?QWfILRS8WtqpdKr8dDzyAFcTfWhkanFlBzfsNh/xLz75jDVyNdylYWUAsoEz?= =?us-ascii?Q?nH+VgvYmk6/8d0XqUNPLtYEA0aJqVgRi6EQYQaWrG0s3Ia54tpVx8s7R9OXS?= =?us-ascii?Q?vaVDElSvnLEyKF2VBfTiYia8u5YukI7qjQ/nMqz37GJ4zgYTP/6D8HPgBPvM?= =?us-ascii?Q?iXLChx9CNXJ9MupIgaTkU8vjGxrQN1YIRxSUhUyzk0T7KfMBrVxDTLovgtaq?= =?us-ascii?Q?w8tw4iWzT+I70JZDmedd/1n3s0tlUnZGnra80uy0MUh7FBoK8K0B8OQYp2lG?= =?us-ascii?Q?jEqM7GhwGAbOIeEOP28V5EacGS7NS14zL8b/ethadP/Z9deBopSUnA/u7mer?= =?us-ascii?Q?pgwWoAJXVLtuuuu8FDR+xtBI/80v7Rx38GW5RmC9RVM52Q3zhZ3sQylpC0oU?= =?us-ascii?Q?d2KAw5LF5bcE7LnS6m8Cay494Lb+DjjwsbN499V71c+xpCyxBNUCR08Tvj7Z?= =?us-ascii?Q?Own5NRgq/s22QjmQzkb9DzdLuE4jAEvPNlll4ZWZgGMCiDxhW+erRrhnh5oI?= =?us-ascii?Q?bWyHpaHrRq9X3pZIHwK4Cy37fJVTf6td6rGHyHK9M3WgE9m7AdI0s7BWpPF9?= =?us-ascii?Q?ZMAQKhnVQunTdfSA8D+XbPkR/BvaCnWtxEF7tCPI4/luYqo3x9gtUTZ6OswX?= =?us-ascii?Q?I5UZNj/+H+E59Bz5oUUhhCmg0U2A8nx5hHtNClWipY9fGVLqeuIKurM5i1dc?= =?us-ascii?Q?sNODfbwWjXVSS8z7RO/84zZtL9OBJXqUplL1o4EY4aXFsgkqud6T6oXnrgvB?= =?us-ascii?Q?q23e7SNwMbKX4iUGCLmQqN2YEFSYQR9OZINvNkQBm8Qal1DX3Dukj7Q4+8M9?= =?us-ascii?Q?3HdvPjOmQz25W1Mc+a5CtYPrklHHSHuYyJsP1uXDiPzJpEmXUuqev6d0hj0q?= =?us-ascii?Q?FH3xjgqQESXiZvtN7zPr+aAHcYQWfLKsuJnFKU+ErdsmHk6EtmjyYuiL1XET?= =?us-ascii?Q?y0DhxaIoK2qsKqPLbRoLm2X7M3GN2JIF8/y8KJsb?= X-OriginatorOrg: garyguo.net X-MS-Exchange-CrossTenant-Network-Message-Id: 939066d6-101c-4a3d-cce0-08de39162689 X-MS-Exchange-CrossTenant-AuthSource: LO2P265MB5183.GBRP265.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Dec 2025 00:34:03.3070 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: bbc898ad-b10f-4e10-8552-d9377b823d45 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Yd5tKS1CC8/zB6cDLJBEZI8fad1xhLGw5em2iCZnJkF8GQjVGzXU8r2Gwxd+QGT6vo/BsZ3TZODG+f6VZDUf8A== X-MS-Exchange-Transport-CrossTenantHeadersStamped: LO0P265MB6037 On Fri, 12 Dec 2025 08:09:18 +0900 FUJITA Tomonori wrote: > Implement Send and Sync for SetOnce to allow it to be used across > thread boundaries. > > Send: SetOnce can be transferred across threads when T: Send, as > the contained value is also transferred and will be dropped on the > destination thread. > > Sync: SetOnce can be shared across threads when T: Sync, as > as_ref() provides shared references &T and atomic operations ensure > proper synchronization. > > Signed-off-by: FUJITA Tomonori > --- > rust/kernel/sync/set_once.rs | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/rust/kernel/sync/set_once.rs b/rust/kernel/sync/set_once.rs > index 889d37dfd17f..5894d0dda14e 100644 > --- a/rust/kernel/sync/set_once.rs > +++ b/rust/kernel/sync/set_once.rs > @@ -127,3 +127,10 @@ fn drop(&mut self) { > } > } > } > + > +// SAFETY: `SetOnce` can be transferred across thread boundaries iff the data it contains can. > +unsafe impl Send for SetOnce {} > + > +// SAFETY: `SetOnce` synchronises access to the inner value via atomic operations, so it is `Sync` > +// as long as the data it contains is `Sync`. > +unsafe impl Sync for SetOnce {} This needs to be `T: Send + Sync` as `T` can be destroyed on a different thread that creates it. Best, Gary