Now that ResourceSize has been moved to kernel::io, import it from the
io module instead of the io::resource sub-module. It makes sense in this
case since the dma_len isn't really related to the Resource type even
though both are sizes of allocations in physical ram.
Signed-off-by: Alice Ryhl <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Danilo Krummrich <[email protected]>
Add a safe Rust abstraction for the kernel's scatter-gather list
facilities (`struct scatterlist` and `struct sg_table`).
This commit introduces `SGTable<T>`, a wrapper that uses a generic
parameter to provide compile-time guarantees about ownership and lifetime.
The abstraction provides two primary states:
- `SGTable<Owned<P>>`: Represents a table whose resources are fully
managed by Rust. It takes ownership of a page provider `P`, allocates
the underlying `struct sg_table`, maps it for DMA, and handles all
cleanup automatically upon drop. The DMA mapping's lifetime is tied to
the associated device using `Devres`, ensuring it is correctly unmapped
before the device is unbound.
- `SGTable<Borrowed>` (or just `SGTable`): A zero-cost representation of
an externally managed `struct sg_table`. It is created from a raw
pointer using `SGTable::from_raw()` and provides a lifetime-bound
reference (`&'a SGTable`) for operations like iteration.
The API exposes a safe iterator that yields `&SGEntry` references,
allowing drivers to easily access the DMA address and length of each
segment in the list.
Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Alexandre Courbot <[email protected]>
Tested-by: Alexandre Courbot <[email protected]>
Reviewed-by: Daniel Almeida <[email protected]>
Reviewed-by: Lyude Paul <[email protected]>
Co-developed-by: Abdiel Janulgue <[email protected]>
Signed-off-by: Abdiel Janulgue <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Danilo Krummrich <[email protected]>
Shankari Anand