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 935e1d90bf6f ("rust: pci:
require Send for Driver trait implementers") from the driver-core tree,
which fixes a missing concurrency requirement, and commit 9901addae63b
("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: Stephen Rothwell <[email protected]>
Closes: https://lore.kernel.org/linux-next/[email protected]/ [1]
Signed-off-by: Danilo Krummrich <[email protected]>
Reviewed-by: Boqun Feng <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Added number to Closes. Fix typo spotted by Boqun. - Miguel ]
Signed-off-by: Miguel Ojeda <[email protected]>

0 files changed, 0 insertions, 0 deletions