Commit 28bb48c4 authored by Danilo Krummrich's avatar Danilo Krummrich Committed by Miguel Ojeda
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rust: dma: add `Send` implementation for `CoherentAllocation` 



Stephen found a future build failure in linux-next [1]:

    error[E0277]: `*mut MyStruct` cannot be sent between threads safely
      --> samples/rust/rust_dma.rs:47:22
       |
    47 | impl pci::Driver for DmaSampleDriver {
       |                      ^^^^^^^^^^^^^^^ `*mut MyStruct` cannot be sent between threads safely

It is caused by the interaction between commit 935e1d90 ("rust: pci:
require Send for Driver trait implementers") from the driver-core tree,
which fixes a missing concurrency requirement, and commit 9901adda
("samples: rust: add Rust dma test sample driver") which adds a sample
that does not satisfy that requirement.

Add a `Send` implementation to `CoherentAllocation`, which allows the
sample (and other future users) to satisfy it.

Reported-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/linux-next/20250324215702.1515ba92@canb.auug.org.au/

 [1]
Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
Reviewed-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20250324174048.1075597-1-ojeda@kernel.org


[ Added number to Closes. Fix typo spotted by Boqun. - Miguel ]
Signed-off-by: default avatarMiguel Ojeda <ojeda@kernel.org>
parent a0b539ad

rust/kernel/dma.rs

+4 −0
Original line number Diff line number Diff line
@@ -301,6 +301,10 @@ fn drop(&mut self) { 
    }

}



// SAFETY: It is safe to send a `CoherentAllocation` to another thread if `T`

// can be sent to another thread.

unsafe impl<T: AsBytes + FromBytes + Send> Send for CoherentAllocation<T> {}



/// Reads a field of an item from an allocated region of structs.

///

/// # Examples