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 license: "GPL v2",
32}
33
34struct NullBlkModule {
35 _disk: Pin<Box<Mutex<GenDisk<NullBlkDevice>>>>,
36}
37
38impl kernel::Module for NullBlkModule {
39 fn init(_module: &'static ThisModule) -> Result<Self> {
40 pr_info!("Rust null_blk loaded\n");
41 let tagset = Arc::pin_init(TagSet::new(1, 256, 1), flags::GFP_KERNEL)?;
42
43 let disk = gen_disk::GenDiskBuilder::new()
44 .capacity_sectors(4096 << 11)
45 .logical_block_size(4096)?
46 .physical_block_size(4096)?
47 .rotational(false)
48 .build(format_args!("rnullb{}", 0), tagset)?;
49
50 let disk = Box::pin_init(new_mutex!(disk, "nullb:disk"), flags::GFP_KERNEL)?;
51
52 Ok(Self { _disk: disk })
53 }
54}
55
56struct NullBlkDevice;
57
58#[vtable]
59impl Operations for NullBlkDevice {
60 #[inline(always)]
61 fn queue_rq(rq: ARef<mq::Request<Self>>, _is_last: bool) -> Result {
62 mq::Request::end_ok(rq)
63 .map_err(|_e| kernel::error::code::EIO)
64 // We take no refcounts on the request, so we expect to be able to
65 // end the request. The request reference must be unique at this
66 // point, and so `end_ok` cannot fail.
67 .expect("Fatal error - expected to be able to end request");
68
69 Ok(())
70 }
71
72 fn commit_rqs() {}
73}