Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2
3//! This is a Rust implementation of the C null block driver.
4//!
5//! Supported features:
6//!
7//! - blk-mq interface
8//! - direct completion
9//! - block size 4k
10//!
11//! The driver is not configurable.
12
13use kernel::{
14 alloc::flags,
15 block::mq::{
16 self,
17 gen_disk::{self, GenDisk},
18 Operations, TagSet,
19 },
20 error::Result,
21 new_mutex, pr_info,
22 prelude::*,
23 sync::{Arc, Mutex},
24 types::ARef,
25};
26
27module! {
28 type: NullBlkModule,
29 name: "rnull_mod",
30 author: "Andreas Hindborg",
31 description: "Rust implementation of the C null block driver",
32 license: "GPL v2",
33}
34
35struct NullBlkModule {
36 _disk: Pin<KBox<Mutex<GenDisk<NullBlkDevice>>>>,
37}
38
39impl kernel::Module for NullBlkModule {
40 fn init(_module: &'static ThisModule) -> Result<Self> {
41 pr_info!("Rust null_blk loaded\n");
42 let tagset = Arc::pin_init(TagSet::new(1, 256, 1), flags::GFP_KERNEL)?;
43
44 let disk = gen_disk::GenDiskBuilder::new()
45 .capacity_sectors(4096 << 11)
46 .logical_block_size(4096)?
47 .physical_block_size(4096)?
48 .rotational(false)
49 .build(format_args!("rnullb{}", 0), tagset)?;
50
51 let disk = KBox::pin_init(new_mutex!(disk, "nullb:disk"), flags::GFP_KERNEL)?;
52
53 Ok(Self { _disk: disk })
54 }
55}
56
57struct NullBlkDevice;
58
59#[vtable]
60impl Operations for NullBlkDevice {
61 #[inline(always)]
62 fn queue_rq(rq: ARef<mq::Request<Self>>, _is_last: bool) -> Result {
63 mq::Request::end_ok(rq)
64 .map_err(|_e| kernel::error::code::EIO)
65 // We take no refcounts on the request, so we expect to be able to
66 // end the request. The request reference must be unique at this
67 // point, and so `end_ok` cannot fail.
68 .expect("Fatal error - expected to be able to end request");
69
70 Ok(())
71 }
72
73 fn commit_rqs() {}
74}