Commit bc5b533b authored by Andreas Hindborg's avatar Andreas Hindborg Committed by Jens Axboe
Browse files

rust: block: add rnull, Rust null_blk implementation 



This patch adds an initial version of the Rust null block driver.

Signed-off-by: default avatarAndreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: default avatarBenno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240611114551.228679-3-nmi@metaspace.dk


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3253aba3

drivers/block/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -354,6 +354,15 @@ config VIRTIO_BLK 
	  This is the virtual block driver for virtio.  It can be used with

          QEMU based VMMs (like KVM or Xen).  Say Y or M.



config BLK_DEV_RUST_NULL

	tristate "Rust null block driver (Experimental)"

	depends on RUST

	help

	  This is the Rust implementation of the null block driver. For now it

	  is only a minimal stub.



	  If unsure, say N.



config BLK_DEV_RBD

	tristate "Rados block device (RBD)"

	depends on INET && BLOCK

drivers/block/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -9,6 +9,9 @@ 
# needed for trace events

ccflags-y				+= -I$(src)



obj-$(CONFIG_BLK_DEV_RUST_NULL) += rnull_mod.o

rnull_mod-y := rnull.o



obj-$(CONFIG_MAC_FLOPPY)	+= swim3.o

obj-$(CONFIG_BLK_DEV_SWIM)	+= swim_mod.o

obj-$(CONFIG_BLK_DEV_FD)	+= floppy.o

drivers/block/rnull.rs

0 → 100644
+73 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



//! This is a Rust implementation of the C null block driver.

//!

//! Supported features:

//!

//! - blk-mq interface

//! - direct completion

//! - block size 4k

//!

//! The driver is not configurable.



use kernel::{

    alloc::flags,

    block::mq::{

        self,

        gen_disk::{self, GenDisk},

        Operations, TagSet,

    },

    error::Result,

    new_mutex, pr_info,

    prelude::*,

    sync::{Arc, Mutex},

    types::ARef,

};



module! {

    type: NullBlkModule,

    name: "rnull_mod",

    author: "Andreas Hindborg",

    license: "GPL v2",

}



struct NullBlkModule {

    _disk: Pin<Box<Mutex<GenDisk<NullBlkDevice>>>>,

}



impl kernel::Module for NullBlkModule {

    fn init(_module: &'static ThisModule) -> Result<Self> {

        pr_info!("Rust null_blk loaded\n");

        let tagset = Arc::pin_init(TagSet::new(1, 256, 1), flags::GFP_KERNEL)?;



        let disk = gen_disk::GenDiskBuilder::new()

            .capacity_sectors(4096 << 11)

            .logical_block_size(4096)?

            .physical_block_size(4096)?

            .rotational(false)

            .build(format_args!("rnullb{}", 0), tagset)?;



        let disk = Box::pin_init(new_mutex!(disk, "nullb:disk"), flags::GFP_KERNEL)?;



        Ok(Self { _disk: disk })

    }

}



struct NullBlkDevice;



#[vtable]

impl Operations for NullBlkDevice {

    #[inline(always)]

    fn queue_rq(rq: ARef<mq::Request<Self>>, _is_last: bool) -> Result {

        mq::Request::end_ok(rq)

            .map_err(|_e| kernel::error::code::EIO)

            // We take no refcounts on the request, so we expect to be able to

            // end the request. The request reference must be unique at this

            // point, and so `end_ok` cannot fail.

            .expect("Fatal error - expected to be able to end request");



        Ok(())

    }



    fn commit_rqs() {}

}