linux/rust/helpers/helpers.c
Danilo Krummrich 05aa6fb1c2 rust: scatterlist: Add abstraction for sg_table
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 <aliceryhl@google.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Tested-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Co-developed-by: Abdiel Janulgue <abdiel.janulgue@gmail.com>
Signed-off-by: Abdiel Janulgue <abdiel.janulgue@gmail.com>
Link: https://lore.kernel.org/r/20250828133323.53311-4-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-09-04 23:33:50 +02:00

54 lines
1.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Non-trivial C macros cannot be used in Rust. Similarly, inlined C functions
* cannot be called either. This file explicitly creates functions ("helpers")
* that wrap those so that they can be called from Rust.
*
* Sorted alphabetically.
*/
#include "auxiliary.c"
#include "blk.c"
#include "bug.c"
#include "build_assert.c"
#include "build_bug.c"
#include "clk.c"
#include "completion.c"
#include "cpu.c"
#include "cpufreq.c"
#include "cpumask.c"
#include "cred.c"
#include "device.c"
#include "dma.c"
#include "drm.c"
#include "err.c"
#include "fs.c"
#include "io.c"
#include "jump_label.c"
#include "kunit.c"
#include "mm.c"
#include "mutex.c"
#include "of.c"
#include "page.c"
#include "pci.c"
#include "pid_namespace.c"
#include "platform.c"
#include "poll.c"
#include "property.c"
#include "rbtree.c"
#include "rcu.c"
#include "refcount.c"
#include "regulator.c"
#include "scatterlist.c"
#include "security.c"
#include "signal.c"
#include "slab.c"
#include "spinlock.c"
#include "sync.c"
#include "task.c"
#include "time.c"
#include "uaccess.c"
#include "vmalloc.c"
#include "wait.c"
#include "workqueue.c"
#include "xarray.c"