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Message-Id: <20230625121657.3631109-9-changxian.cqs@antgroup.com>
Date: Sun, 25 Jun 2023 20:16:57 +0800
From: "Qingsong Chen" <changxian.cqs@...group.com>
To: linux-kernel@...r.kernel.org
Cc: "田洪亮" <tate.thl@...group.com>,
"Qingsong Chen" <changxian.cqs@...group.com>,
"Miguel Ojeda" <ojeda@...nel.org>,
"Alex Gaynor" <alex.gaynor@...il.com>,
"Wedson Almeida Filho" <wedsonaf@...il.com>,
"Boqun Feng" <boqun.feng@...il.com>, "Gary Guo" <gary@...yguo.net>,
"Björn Roy Baron" <bjorn3_gh@...tonmail.com>,
"Benno Lossin" <benno.lossin@...ton.me>,
<rust-for-linux@...r.kernel.org>
Subject: [RFC PATCH 8/8] samples: rust: add a device mapper linear target
Add a device mapper linear target sample, based on the
rust device_mapper abstractions.
Signed-off-by: Qingsong Chen <changxian.cqs@...group.com>
---
samples/rust/Kconfig | 10 ++
samples/rust/Makefile | 1 +
samples/rust/rust_dm_linear.rs | 257 +++++++++++++++++++++++++++++++++
3 files changed, 268 insertions(+)
create mode 100644 samples/rust/rust_dm_linear.rs
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index b0f74a81c8f9..0d532c995f9a 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -30,6 +30,16 @@ config SAMPLE_RUST_PRINT
If unsure, say N.
+config SAMPLE_RUST_DM_LINEAR
+ tristate "Device mapper linear target"
+ help
+ This option builds the Rust device mapper linear sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_dm_linear.
+
+ If unsure, say N.
+
config SAMPLE_RUST_HOSTPROGS
bool "Host programs"
help
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index 03086dabbea4..cf4bf82312d8 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -2,5 +2,6 @@
obj-$(CONFIG_SAMPLE_RUST_MINIMAL) += rust_minimal.o
obj-$(CONFIG_SAMPLE_RUST_PRINT) += rust_print.o
+obj-$(CONFIG_SAMPLE_RUST_DM_LINEAR) += rust_dm_linear.o
subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS) += hostprogs
diff --git a/samples/rust/rust_dm_linear.rs b/samples/rust/rust_dm_linear.rs
new file mode 100644
index 000000000000..1f338e6b227f
--- /dev/null
+++ b/samples/rust/rust_dm_linear.rs
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust device mapper linear target sample.
+//!
+//! C version: drivers/md/dm-linear.c
+
+use core::ops::Range;
+use core::ptr::NonNull;
+use kernel::bindings::PAGE_SECTORS_SHIFT;
+use kernel::device_mapper::*;
+use kernel::prelude::*;
+use kernel::{c_str, fmt, str::CString};
+
+module! {
+ type: RustDmLinear,
+ name: "rust_dm_linear",
+ author: "Rust for Linux Contributors",
+ description: "Rust device mapper linear target sample",
+ license: "GPL",
+}
+
+struct Linear {
+ dev: TargetDevice<Self>,
+ start: usize,
+}
+
+impl Linear {
+ fn new(dev: TargetDevice<Self>, start: usize) -> impl Init<Self> {
+ init!(Self { dev, start })
+ }
+
+ fn map_sector(&self, sector: usize, base: usize) -> usize {
+ sector - base + self.start
+ }
+}
+
+// SAFETY: `Linear` could be used from all threads.
+unsafe impl Sync for Linear {}
+
+#[vtable]
+impl TargetOperations for Linear {
+ type Private = Linear;
+
+ fn ctr(t: &mut Target<Self>, args: Args) -> Result<Box<Linear>> {
+ if args.len() != 2 {
+ t.set_error(c_str!("Invalid argument count"));
+ return Err(EINVAL);
+ }
+
+ let dev = match t.get_device(&args[0]) {
+ Ok(dev) => dev,
+ Err(e) => {
+ t.set_error(c_str!("Device lookup failed"));
+ return Err(e);
+ }
+ };
+
+ let start = &args[1].to_str().map_err(|_| EINVAL)?;
+ let start = usize::from_str_radix(start, 10).map_err(|_| {
+ t.set_error(c_str!("Invalid device sector"));
+ EINVAL
+ })?;
+
+ t.set_num_flush_bios(1);
+ t.set_num_discard_bios(1);
+ t.set_num_secure_erase_bios(1);
+ t.set_num_write_zeroes_bios(1);
+
+ Box::init(Linear::new(dev, start))
+ }
+
+ fn dtr(_: &mut Target<Self>) {}
+
+ fn map(t: &mut Target<Self>, mut bio: Pin<&mut Bio>) -> MapState {
+ let Some(linear) = t.private() else {
+ pr_warn!("Error, found no rust_linear\n");
+ return MapState::Kill;
+ };
+
+ let offset = bio.sector() - linear.dev.target().begin_sector();
+ bio.set_dev(&linear.dev);
+ bio.set_sector(linear.start + offset);
+ MapState::Remapped
+ }
+
+ fn status(t: &mut Target<Self>, type_: StatusType, _: StatusFlags) -> Option<CString> {
+ let Some(linear) = t.private() else {
+ pr_warn!("Error, found no rust_linear\n");
+ return None;
+ };
+
+ match type_ {
+ StatusType::Info => None,
+ StatusType::Table => {
+ CString::try_from_fmt(fmt!("{} {}", linear.dev.device_name(), linear.start)).ok()
+ }
+ StatusType::Ima => {
+ let version = linear.dev.target().version();
+ CString::try_from_fmt(fmt!(
+ "target_name={},target_version={}.{}.{},device_name={},start={};",
+ linear.dev.target().name(),
+ version[0],
+ version[1],
+ version[2],
+ linear.dev.device_name(),
+ linear.start
+ ))
+ .ok()
+ }
+ _ => {
+ pr_warn!("Unsupported dm_status_type\n");
+ None
+ }
+ }
+ }
+
+ fn prepare_ioctl(t: &mut Target<Self>) -> (i32, Option<NonNull<TargetDevice<Self>>>) {
+ let Some(mut linear) = t.private() else {
+ pr_warn!("Error, found no rust_linear\n");
+ return (EINVAL.to_errno(), None);
+ };
+
+ let mut ret = 0;
+ if linear.start > 0 || linear.dev.target().total_sectors() != linear.dev.device_sectors() {
+ ret = 1;
+ }
+ (ret, Some(linear.dev.as_ptr()))
+ }
+
+ fn iterate_devices(t: &mut Target<Self>) -> Result<Box<dyn Iterator<Item = IterDevice<Self>>>> {
+ let Some(mut linear) = t.private() else {
+ pr_warn!("Error, found no rust_linear\n");
+ return Err(EINVAL);
+ };
+
+ Ok(Box::init(IterLinear::new(
+ linear.dev.as_ptr(),
+ linear.start,
+ t.total_sectors(),
+ ))?)
+ }
+
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ fn report_zones(t: &mut Target<Self>, args: &mut [ReportZonesArgs]) -> Result {
+ if args.len() == 0 {
+ pr_warn!("Invalid report_zones_args\n");
+ return Err(EINVAL);
+ }
+
+ let Some(linear) = t.private() else {
+ pr_warn!("Error, found no rust_linear\n");
+ return Err(EINVAL);
+ };
+
+ let sector = linear.map_sector(args[0].next_sector(), linear.dev.target().begin_sector());
+ linear.dev.report_zones(linear.start, sector, args)
+ }
+
+ #[cfg(CONFIG_FS_DAX)]
+ fn direct_access(
+ t: &mut Target<Self>,
+ pgoff: usize,
+ nr_pages: usize,
+ mode: DaxMode,
+ ) -> Result<(usize, Range<usize>)> {
+ let base = t.begin_sector();
+ let Some(mut linear) = t.private() else {
+ pr_warn!("Error, found no rust_linear\n");
+ return Err(EINVAL);
+ };
+
+ let sector = linear.map_sector(pgoff << PAGE_SECTORS_SHIFT, base);
+ let offset = (linear.dev.device_sectors() + sector) >> PAGE_SECTORS_SHIFT;
+ linear.dev.dax_direct_access(offset, nr_pages, mode)
+ }
+
+ #[cfg(CONFIF_FS_DAX)]
+ fn dax_zero_page_range(t: &mut Target<Self>, pgoff: usize, nr_pages: usize) -> Result {
+ let base = t.begin_sector();
+ let Some(mut linear) = t.private() else {
+ pr_warn!("Error, found no rust_linear\n");
+ return Err(EINVAL);
+ };
+
+ let sector = linear.map_sector(pgoff << PAGE_SECTORS_SHIFT, base);
+ let offset = (linear.dev.device_sectors() + sector) >> PAGE_SECTORS_SHIFT;
+ linear.dev.dax_zero_page_range(offset, nr_pages)
+ }
+
+ #[cfg(CONFIF_FS_DAX)]
+ fn dax_recovery_write(
+ t: &mut Target<Self>,
+ iov_iter: Pin<&mut IovIter>,
+ pgoff: usize,
+ region: Range<usize>,
+ ) -> usize {
+ let base = t.begin_sector();
+ let Some(mut linear) = t.private() else {
+ pr_warn!("Error, found no rust_linear\n");
+ return 0;
+ };
+
+ let sector = linear.map_sector(pgoff << PAGE_SECTORS_SHIFT, base);
+ let offset = (linear.dev.device_sectors() + sector) >> PAGE_SECTORS_SHIFT;
+ linear.dev.dax_recovery_write(iov_iter, offset, region)
+ }
+}
+
+struct IterLinear {
+ item: Option<IterDevice<Linear>>,
+}
+
+impl IterLinear {
+ fn new(dev: NonNull<TargetDevice<Linear>>, start: usize, len: usize) -> impl Init<Self> {
+ init!(Self {
+ item: Some((dev, start, len))
+ })
+ }
+}
+
+impl Iterator for IterLinear {
+ type Item = IterDevice<Linear>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.item.take()
+ }
+}
+
+struct RustDmLinear(Pin<Box<TargetType>>);
+
+impl kernel::Module for RustDmLinear {
+ fn init(_module: &'static ThisModule) -> Result<Self> {
+ pr_info!("Rust device mapper linear target sample (init)\n");
+
+ let target = Box::pin_init(TargetType::register::<Linear>(
+ _module,
+ c_str!("rust_linear"),
+ [0, 0, 1],
+ 0,
+ ));
+
+ let target = match target {
+ Ok(target) => target,
+ Err(e) => {
+ pr_warn!("Target register failed, errno: {}\n", e.to_errno());
+ return Err(e);
+ }
+ };
+ Ok(RustDmLinear(target))
+ }
+}
+
+impl Drop for RustDmLinear {
+ fn drop(&mut self) {
+ pr_info!("Rust device mapper linear target sample (exit)\n");
+ }
+}
--
2.40.1
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