The `Send` implementation for `GenDisk` was conditioned on `T: Send`. This constrains the wrong type. `T` is the `Operations` implementation, which is typically a zero-sized marker type that carries no data, so `T: Send` says nothing about whether the data a `GenDisk` actually owns can be moved to another thread. A `GenDisk` owns the queue data `T::QueueData` (stored as the `gendisk`'s `queuedata` and dropped when the `GenDisk` is dropped) and an `Arc>`. These are the values transferred when a `GenDisk` is sent across a thread boundary, so the `Send` bound must constrain exactly them. Bound `T::QueueData: Send` and `Arc>: Send` instead. Fixes: 3253aba3408a ("rust: block: introduce `kernel::block::mq` module") Suggested-by: Yuan Tan Signed-off-by: Andreas Hindborg --- Please take patch from Yuan instead of this one, if they send a fixed version [1]. [1] https://lore.kernel.org/r/8839ddc5ff54bf454d508cde91d27d00fc3e2dd8.1780633578.git.ytan089@ucr.edu --- rust/kernel/block/mq/gen_disk.rs | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs index 912cb805caf5..b36d24382cc3 100644 --- a/rust/kernel/block/mq/gen_disk.rs +++ b/rust/kernel/block/mq/gen_disk.rs @@ -199,8 +199,14 @@ pub struct GenDisk { } // SAFETY: `GenDisk` is an owned pointer to a `struct gendisk` and an `Arc` to a -// `TagSet` It is safe to send this to other threads as long as T is Send. -unsafe impl Send for GenDisk {} +// `TagSet`. It is safe to send this to other threads as long as these two are `Send`. +unsafe impl Send for GenDisk +where + T: Operations, + T::QueueData: Send, + Arc>: Send, +{ +} impl Drop for GenDisk { fn drop(&mut self) { -- 2.51.2