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There > is no way to express a backend, or a view, that can only be read or only > be written. > > Thus, replace `IoCapable` with an `IoReadable` trait holding > `io_read` and an `IoWritable` trait holding `io_write`, and implement > both for all existing backends. The non-copy `Io` methods that read a > value now require `IoReadable` and those that write one require > `IoWritable`. `update` and `try_update` read and then write, so they > require both. > > The copy methods use `IoCopyable` and are not changed here. > > No functional change intended. This prepares for read-only and write-only > views, added in a following patch. I think by Rust convention these should be named `IoRead`/`IoWrite`, but we= 've aleady named this `IoCapable` and I further made the mistake of adding `IoCopyable`... So I guess I'm not in a good position to ask for name change, but we should consider it. Apart from the name: Reviewed-by: Gary Guo Best, Gary > > Signed-off-by: Daniel Almeida > --- > rust/kernel/dma.rs | 12 ++++-- > rust/kernel/io.rs | 101 +++++++++++++++++++++++++++++---------------= ------ > rust/kernel/pci/io.rs | 10 +++-- > 3 files changed, 75 insertions(+), 48 deletions(-)