diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index 5b9d4aaebb81..ed209f4f2798 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -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 diff --git a/drivers/block/Makefile b/drivers/block/Makefile index 101612cba303..1105a2d4fdcb 100644 --- a/drivers/block/Makefile +++ b/drivers/block/Makefile @@ -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 diff --git a/drivers/block/rnull.rs b/drivers/block/rnull.rs new file mode 100644 index 000000000000..b0227cf9ddd3 --- /dev/null +++ b/drivers/block/rnull.rs @@ -0,0 +1,73 @@ +// 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>>>, +} + +impl kernel::Module for NullBlkModule { + fn init(_module: &'static ThisModule) -> Result { + 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>, _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() {} +}