From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9F39430E0E3; Fri, 22 Aug 2025 12:16:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755864986; cv=none; b=MnEDcqdXFjmUgI09p9QsAYhm/TqFB2l27p0q1A51j70uydaEOkO7tGrCJ6hvM4Tvv7V3nbg3jDRD3EoFgff85/Ab/m3CaQGrOdpPmTg7aUdn1TC8mr503AgQJdvZQgoQNXAxdowF2ujM/kFgaN5QDzjydz7WCNCgFCgW9cfe48U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755864986; c=relaxed/simple; bh=iW4yDCdWglsE+9DJN1QwjcjeXTNvaRhTe3qyZwnbuV4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=fBaqpQiGtbk79AOTkIMAxKfDK7HVdzFHVVyzCZX92aHloNKBv6AGWjCPv9KvQTco+/RFAIfQgBdIW6RWnAHDZD3diqrurgAvUQs0Vlv0eIhlJIU5shjEnWRMBxtBla6ybxeTg6udKJAL85FmTeBqzZRVsFpgcEObcDW88/tmdBE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=F5kSOHAj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="F5kSOHAj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 59C9DC4CEED; Fri, 22 Aug 2025 12:16:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755864986; bh=iW4yDCdWglsE+9DJN1QwjcjeXTNvaRhTe3qyZwnbuV4=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=F5kSOHAjTL69SW+2oyROThVneKvWw7if+tPNMyZXHwQ6Z5VD9V+5UaKyBBhjIReTR 9zAp4ytX7gJxRmH5XYMuZ6nvHqZchXw/kVFtRJ9AfSVGESxCnBV7TNMsx4eDH2GKWY PzGjGv0J3fz3LGWfvtE7DvfAD0o3eBVIxArdGxiL0hzpStSztVRo7/+Z5jLy3/Jxh3 ldKDSCN0CXKcBIoWgUzAL1rOqKFrc0Iu15rGUZgrp5ZCkhQfLCIWyDWkssEMn78TGo Ar7c/uMmyGGzFUGbr26ofr6CADJaIxH+COk80f046Np5bwBi/sXAso7dKkaglGdKt4 n1c0MvPiuNAMA== From: Andreas Hindborg Date: Fri, 22 Aug 2025 14:14:50 +0200 Subject: [PATCH v6 14/18] rnull: enable configuration via `configfs` Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20250822-rnull-up-v6-16-v6-14-ec65006e2f07@kernel.org> References: <20250822-rnull-up-v6-16-v6-0-ec65006e2f07@kernel.org> In-Reply-To: <20250822-rnull-up-v6-16-v6-0-ec65006e2f07@kernel.org> To: Boqun Feng , Miguel Ojeda , Alex Gaynor , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Alice Ryhl , Trevor Gross , Danilo Krummrich , Jens Axboe , Breno Leitao Cc: linux-block@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Andreas Hindborg X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=10549; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=iW4yDCdWglsE+9DJN1QwjcjeXTNvaRhTe3qyZwnbuV4=; b=owEBbQKS/ZANAwAIAeG4Gj55KGN3AcsmYgBoqF8+c7BLemjjK/8SdYg0VzN5/42FjSr7yUTRF ZkmkF3eeYmJAjMEAAEIAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCaKhfPgAKCRDhuBo+eShj dzTiD/0bjy0NPt6q3dRTSYNJfq2FpMzH1mamhEZY51Me13GfCRS/zuUaf9C1Y9SQ8FAhkNqAKp9 I/Lw8iG2u0NlfW/om/LXRyrfD5jECPNQlcKV1dYQFAEEM63fAcUvkc9MZoGs19J8nofTQTKFBhV DAkaIgRlfPMqEpW4pvn0Y56zY2t0tt2I3DwbqqPiRhXrwO1WW2XlfZpc1NfH1Tnnq8PXC/bmv/N LR1+Y1/3poZHA7NzKevcwqyRZDYnWUQU9mFwe0dHNLvrwex2cY+gjMm13H9uZxpxUQQs4eCLgAN aNwrW7DKxgfCfxxoJVQ/LClwI4YPc3pu1S1d6mdl4dy1ER4NOQExMzs4s+oFiXvhgs3FiO24hpr 6sJxE8LTznVSd+798V26w3+J2UamOvwi8rvvJVC4GC4OGMG8gv819/L5uW4pwElAJ+J+44XJSQ5 dsO6ckx/ZdyMkZxDKp7okXmtvD6gvZfSeYZregLx+Hzxv1P1/fDEm9TqbX/MUUEGnWlwHEi2p4Z 2nBr6+7+m/ieSS0tKQzPq22YrKCNvP9uszrKGTQogLEaqANG6nW60cjMkUXpHIPEEYAijy36APy LBi/rYhDA04iBsG+om5/DcXe2IAxxhabufPlfPoWu01zulxiOQgp29VXl+HBMrGDdi2sYPQRdJA qhcqYTuABrK8xFQ== X-Developer-Key: i=a.hindborg@kernel.org; a=openpgp; fpr=3108C10F46872E248D1FB221376EB100563EF7A7 Allow rust null block devices to be configured and instantiated via `configfs`. Reviewed-by: Alice Ryhl Signed-off-by: Andreas Hindborg --- drivers/block/rnull/Kconfig | 2 +- drivers/block/rnull/configfs.rs | 207 +++++++++++++++++++++++++++++++++++++++ drivers/block/rnull/rnull.rs | 59 +++++------ rust/kernel/block/mq/gen_disk.rs | 2 +- 4 files changed, 240 insertions(+), 30 deletions(-) diff --git a/drivers/block/rnull/Kconfig b/drivers/block/rnull/Kconfig index 6dc5aff96bf4..7bc5b376c128 100644 --- a/drivers/block/rnull/Kconfig +++ b/drivers/block/rnull/Kconfig @@ -4,7 +4,7 @@ config BLK_DEV_RUST_NULL tristate "Rust null block driver (Experimental)" - depends on RUST + depends on RUST && CONFIGFS_FS help This is the Rust implementation of the null block driver. Like the C version, the driver allows the user to create virutal block diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs new file mode 100644 index 000000000000..46710a1e1af4 --- /dev/null +++ b/drivers/block/rnull/configfs.rs @@ -0,0 +1,207 @@ +// SPDX-License-Identifier: GPL-2.0 + +use super::{NullBlkDevice, THIS_MODULE}; +use core::fmt::Write; +use kernel::{ + block::mq::gen_disk::{GenDisk, GenDiskBuilder}, + c_str, + configfs::{self, AttributeOperations}, + configfs_attrs, new_mutex, + page::PAGE_SIZE, + prelude::*, + str::{kstrtobool_bytes, CString}, + sync::Mutex, +}; +use pin_init::PinInit; + +pub(crate) fn subsystem() -> impl PinInit, Error> { + let item_type = configfs_attrs! { + container: configfs::Subsystem, + data: Config, + child: DeviceConfig, + attributes: [ + features: 0, + ], + }; + + kernel::configfs::Subsystem::new(c_str!("rnull"), item_type, try_pin_init!(Config {})) +} + +#[pin_data] +pub(crate) struct Config {} + +#[vtable] +impl AttributeOperations<0> for Config { + type Data = Config; + + fn show(_this: &Config, page: &mut [u8; PAGE_SIZE]) -> Result { + let mut writer = kernel::str::Formatter::new(page); + writer.write_str("blocksize,size,rotational\n")?; + Ok(writer.bytes_written()) + } +} + +#[vtable] +impl configfs::GroupOperations for Config { + type Child = DeviceConfig; + + fn make_group( + &self, + name: &CStr, + ) -> Result, Error>> { + let item_type = configfs_attrs! { + container: configfs::Group, + data: DeviceConfig, + attributes: [ + // Named for compatibility with C null_blk + power: 0, + blocksize: 1, + rotational: 2, + size: 3, + ], + }; + + Ok(configfs::Group::new( + name.try_into()?, + item_type, + // TODO: cannot coerce new_mutex!() to impl PinInit<_, Error>, so put mutex inside + try_pin_init!( DeviceConfig { + data <- new_mutex!(DeviceConfigInner { + powered: false, + block_size: 4096, + rotational: false, + disk: None, + capacity_mib: 4096, + name: name.try_into()?, + }), + }), + )) + } +} + +#[pin_data] +pub(crate) struct DeviceConfig { + #[pin] + data: Mutex, +} + +#[pin_data] +struct DeviceConfigInner { + powered: bool, + name: CString, + block_size: u32, + rotational: bool, + capacity_mib: u64, + disk: Option>, +} + +#[vtable] +impl configfs::AttributeOperations<0> for DeviceConfig { + type Data = DeviceConfig; + + fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result { + let mut writer = kernel::str::Formatter::new(page); + + if this.data.lock().powered { + writer.write_str("1\n")?; + } else { + writer.write_str("0\n")?; + } + + Ok(writer.bytes_written()) + } + + fn store(this: &DeviceConfig, page: &[u8]) -> Result { + let power_op = kstrtobool_bytes(page)?; + let mut guard = this.data.lock(); + + if !guard.powered && power_op { + guard.disk = Some(NullBlkDevice::new( + &guard.name, + guard.block_size, + guard.rotational, + guard.capacity_mib, + )?); + guard.powered = true; + } else if guard.powered && !power_op { + drop(guard.disk.take()); + guard.powered = false; + } + + Ok(()) + } +} + +#[vtable] +impl configfs::AttributeOperations<1> for DeviceConfig { + type Data = DeviceConfig; + + fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result { + let mut writer = kernel::str::Formatter::new(page); + writer.write_fmt(fmt!("{}\n", this.data.lock().block_size))?; + Ok(writer.bytes_written()) + } + + fn store(this: &DeviceConfig, page: &[u8]) -> Result { + if this.data.lock().powered { + return Err(EBUSY); + } + + let text = core::str::from_utf8(page)?.trim(); + let value = text.parse::().map_err(|_| EINVAL)?; + + GenDiskBuilder::validate_block_size(value)?; + this.data.lock().block_size = value; + Ok(()) + } +} + +#[vtable] +impl configfs::AttributeOperations<2> for DeviceConfig { + type Data = DeviceConfig; + + fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result { + let mut writer = kernel::str::Formatter::new(page); + + if this.data.lock().rotational { + writer.write_str("1\n")?; + } else { + writer.write_str("0\n")?; + } + + Ok(writer.bytes_written()) + } + + fn store(this: &DeviceConfig, page: &[u8]) -> Result { + if this.data.lock().powered { + return Err(EBUSY); + } + + this.data.lock().rotational = kstrtobool_bytes(page)?; + + Ok(()) + } +} + +#[vtable] +impl configfs::AttributeOperations<3> for DeviceConfig { + type Data = DeviceConfig; + + fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result { + let mut writer = kernel::str::Formatter::new(page); + writer.write_fmt(fmt!("{}\n", this.data.lock().capacity_mib))?; + Ok(writer.bytes_written()) + } + + fn store(this: &DeviceConfig, page: &[u8]) -> Result { + if this.data.lock().powered { + return Err(EBUSY); + } + + let text = core::str::from_utf8(page)?.trim(); + let value = text.parse::().map_err(|_| EINVAL)?; + + this.data.lock().capacity_mib = value; + Ok(()) + } +} diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs index d07e76ae2c13..8690ff5f974f 100644 --- a/drivers/block/rnull/rnull.rs +++ b/drivers/block/rnull/rnull.rs @@ -1,28 +1,25 @@ // 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. + +mod configfs; use kernel::{ - alloc::flags, - block::mq::{ + block::{ self, - gen_disk::{self, GenDisk}, - Operations, TagSet, + mq::{ + self, + gen_disk::{self, GenDisk}, + Operations, TagSet, + }, }, error::Result, - new_mutex, pr_info, + pr_info, prelude::*, - sync::{Arc, Mutex}, + sync::Arc, types::ARef, }; +use pin_init::PinInit; module! { type: NullBlkModule, @@ -35,33 +32,39 @@ #[pin_data] struct NullBlkModule { #[pin] - _disk: Mutex>, + configfs_subsystem: kernel::configfs::Subsystem, } impl kernel::InPlaceModule for NullBlkModule { fn init(_module: &'static ThisModule) -> impl PinInit { pr_info!("Rust null_blk loaded\n"); - // Use a immediately-called closure as a stable `try` block - let disk = /* try */ (|| { - let tagset = Arc::pin_init(TagSet::new(1, 256, 1), flags::GFP_KERNEL)?; - - gen_disk::GenDiskBuilder::new() - .capacity_sectors(4096 << 11) - .logical_block_size(4096)? - .physical_block_size(4096)? - .rotational(false) - .build(format_args!("rnullb{}", 0), tagset) - })(); - try_pin_init!(Self { - _disk <- new_mutex!(disk?, "nullb:disk"), + configfs_subsystem <- configfs::subsystem(), }) } } struct NullBlkDevice; +impl NullBlkDevice { + fn new( + name: &CStr, + block_size: u32, + rotational: bool, + capacity_mib: u64, + ) -> Result> { + let tagset = Arc::pin_init(TagSet::new(1, 256, 1), GFP_KERNEL)?; + + gen_disk::GenDiskBuilder::new() + .capacity_sectors(capacity_mib << (20 - block::SECTOR_SHIFT)) + .logical_block_size(block_size)? + .physical_block_size(block_size)? + .rotational(rotational) + .build(fmt!("{}", name.to_str()?), tagset) + } +} + #[vtable] impl Operations for NullBlkDevice { #[inline(always)] diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs index 20f1d46c774d..6b1b846874db 100644 --- a/rust/kernel/block/mq/gen_disk.rs +++ b/rust/kernel/block/mq/gen_disk.rs @@ -51,7 +51,7 @@ pub fn rotational(mut self, rotational: bool) -> Self { /// Validate block size by verifying that it is between 512 and `PAGE_SIZE`, /// and that it is a power of two. - fn validate_block_size(size: u32) -> Result { + pub fn validate_block_size(size: u32) -> Result { if !(512..=bindings::PAGE_SIZE as u32).contains(&size) || !size.is_power_of_two() { Err(error::code::EINVAL) } else { -- 2.47.2