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From: Andreas Hindborg <a.hindborg@kernel.org>
To: "Boqun Feng" <boqun.feng@gmail.com>,
	"Jens Axboe" <axboe@kernel.dk>, "Miguel Ojeda" <ojeda@kernel.org>,
	"Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <lossin@kernel.org>,
	"Alice Ryhl" <aliceryhl@google.com>,
	"Trevor Gross" <tmgross@umich.edu>,
	"Danilo Krummrich" <dakr@kernel.org>,
	"FUJITA Tomonori" <fujita.tomonori@gmail.com>,
	"Frederic Weisbecker" <frederic@kernel.org>,
	"Lyude Paul" <lyude@redhat.com>,
	"Thomas Gleixner" <tglx@kernel.org>,
	"Anna-Maria Behnsen" <anna-maria@linutronix.de>,
	"John Stultz" <jstultz@google.com>,
	"Stephen Boyd" <sboyd@kernel.org>,
	"Lorenzo Stoakes" <lorenzo.stoakes@oracle.com>,
	"Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: linux-block@vger.kernel.org, rust-for-linux@vger.kernel.org,
	 linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	 Andreas Hindborg <a.hindborg@kernel.org>
Subject: [PATCH 44/79] block: rust: add an abstraction for `bindings::req_op`
Date: Mon, 16 Feb 2026 00:35:31 +0100	[thread overview]
Message-ID: <20260216-rnull-v6-19-rc5-send-v1-44-de9a7af4b469@kernel.org> (raw)
In-Reply-To: <20260216-rnull-v6-19-rc5-send-v1-0-de9a7af4b469@kernel.org>

Add the `Command` enum as a Rust abstraction for block request operation
codes. The enum variants correspond to the C `REQ_OP_*` defines and
include read, write, flush, discard, and zone management operations.

Also add a `command()` method to `Request` to retrieve the operation
code.

Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
 drivers/block/rnull/rnull.rs            |  6 +--
 rust/kernel/block/mq.rs                 |  1 +
 rust/kernel/block/mq/request.rs         | 11 +++++-
 rust/kernel/block/mq/request/command.rs | 65 +++++++++++++++++++++++++++++++++
 4 files changed, 79 insertions(+), 4 deletions(-)

diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 3fb19836ce6ff..9383b82f9a736 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -508,10 +508,10 @@ fn transfer(
                     .len()
                     .min((end_sector - sector) as u32 >> SECTOR_SHIFT);
                 match command {
-                    bindings::req_op_REQ_OP_WRITE => {
+                    mq::Command::Write => {
                         self.write(&mut tree_guard, &mut hw_data_guard, sector, segment)?
                     }
-                    bindings::req_op_REQ_OP_READ => {
+                    mq::Command::Read => {
                         self.read(&mut tree_guard, &mut hw_data_guard, sector, segment)?
                     }
                     _ => (),
@@ -703,7 +703,7 @@ fn queue_rq(
         Self::handle_bad_blocks(this.deref(), &mut rq, &mut sectors)?;
 
         if this.memory_backed {
-            if rq.command() == bindings::req_op_REQ_OP_DISCARD {
+            if rq.command() == mq::Command::Discard {
                 this.discard(&hw_data, rq.sector(), sectors)?;
             } else {
                 this.transfer(&hw_data, &mut rq, sectors)?;
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 02738f52389ba..057a5f366be3a 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -131,6 +131,7 @@
 pub mod tag_set;
 
 pub use operations::Operations;
+pub use request::Command;
 pub use request::IdleRequest;
 pub use request::Request;
 pub use request::RequestTimerHandle;
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index d6f3ffde1c5c4..4e47419776e0f 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -23,6 +23,9 @@
 use crate::block::bio::Bio;
 use crate::block::bio::BioIterator;
 
+mod command;
+pub use command::Command;
+
 /// A [`Request`] that a driver has not yet begun to process.
 ///
 /// A driver can convert an `IdleRequest` to a [`Request`] by calling [`IdleRequest::start`].
@@ -89,11 +92,17 @@ fn deref(&self) -> &Self::Target {
 
 impl<T: Operations> RequestInner<T> {
     /// Get the command identifier for the request
-    pub fn command(&self) -> u32 {
+    fn command_raw(&self) -> u32 {
         // SAFETY: By C API contract and type invariant, `cmd_flags` is valid for read
         unsafe { (*self.0.get()).cmd_flags & ((1 << bindings::REQ_OP_BITS) - 1) }
     }
 
+    /// Get the command of this request.
+    pub fn command(&self) -> Command {
+        // SAFETY: By type invariant of `Self`, `self.0` is valid and live.
+        unsafe { Command::from_raw(self.command_raw()) }
+    }
+
     /// Get the target sector for the request.
     #[inline(always)]
     pub fn sector(&self) -> u64 {
diff --git a/rust/kernel/block/mq/request/command.rs b/rust/kernel/block/mq/request/command.rs
new file mode 100644
index 0000000000000..70a8d67fa35c0
--- /dev/null
+++ b/rust/kernel/block/mq/request/command.rs
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/// Block I/O operation codes.
+///
+/// This is the Rust abstraction for the C [`enum req_op`].
+///
+/// Operations common to the bio and request structures. The kernel uses 8 bits
+/// for encoding the operation, and the remaining 24 bits for flags.
+///
+/// The least significant bit of the operation number indicates the data
+/// transfer direction:
+///
+/// - If the least significant bit is set, transfers are TO the device.
+/// - If the least significant bit is not set, transfers are FROM the device.
+///
+/// If an operation does not transfer data, the least significant bit has no
+/// meaning.
+///
+/// [`enum req_op`]: srctree/include/linux/blk_types.h
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[repr(u32)]
+pub enum Command {
+    /// Read sectors from the device.
+    Read = bindings::req_op_REQ_OP_READ,
+    /// Write sectors to the device.
+    Write = bindings::req_op_REQ_OP_WRITE,
+    /// Flush the volatile write cache.
+    Flush = bindings::req_op_REQ_OP_FLUSH,
+    /// Discard sectors.
+    Discard = bindings::req_op_REQ_OP_DISCARD,
+    /// Securely erase sectors.
+    SecureErase = bindings::req_op_REQ_OP_SECURE_ERASE,
+    /// Write data at the current zone write pointer.
+    ZoneAppend = bindings::req_op_REQ_OP_ZONE_APPEND,
+    /// Write zeroes. This allows to implement zeroing for devices that don't use either discard
+    /// with a predictable zero pattern or WRITE SAME of zeroes.
+    WriteZeroes = bindings::req_op_REQ_OP_WRITE_ZEROES,
+    /// Open a zone.
+    ZoneOpen = bindings::req_op_REQ_OP_ZONE_OPEN,
+    /// Close a zone.
+    ZoneClose = bindings::req_op_REQ_OP_ZONE_CLOSE,
+    /// Transition a zone to full.
+    ZoneFinish = bindings::req_op_REQ_OP_ZONE_FINISH,
+    /// Reset a zone write pointer.
+    ZoneReset = bindings::req_op_REQ_OP_ZONE_RESET,
+    /// Reset all the zones present on the device.
+    ZoneResetAll = bindings::req_op_REQ_OP_ZONE_RESET_ALL,
+    /// Driver private request for data transfer to the driver.
+    DriverIn = bindings::req_op_REQ_OP_DRV_IN,
+    /// Driver private request for data transfer from the driver.
+    DriverOut = bindings::req_op_REQ_OP_DRV_OUT,
+}
+
+impl Command {
+    /// Creates a [`Command`] from a raw `u32` value.
+    ///
+    /// # Safety
+    ///
+    /// The value must be a valid `req_op` operation code.
+    pub unsafe fn from_raw(value: u32) -> Self {
+        // SAFETY: The caller guarantees that the value is a valid operation
+        // code.
+        unsafe { core::mem::transmute(value) }
+    }
+}

-- 
2.51.2




  parent reply	other threads:[~2026-02-16  4:12 UTC|newest]

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
2026-02-15 23:34 ` [PATCH 01/79] block: rnull: adopt new formatting guidelines Andreas Hindborg
2026-02-15 23:34 ` [PATCH 02/79] block: rnull: add module parameters Andreas Hindborg
2026-02-15 23:34 ` [PATCH 03/79] block: rnull: add macros to define configfs attributes Andreas Hindborg
2026-02-15 23:34 ` [PATCH 04/79] block: rust: fix generation of bindings to `BLK_STS_.*` Andreas Hindborg
2026-02-15 23:34 ` [PATCH 05/79] block: rust: change `queue_rq` request type to `Owned` Andreas Hindborg
2026-02-15 23:34 ` [PATCH 06/79] block: rust: add `Request` private data support Andreas Hindborg
2026-02-15 23:34 ` [PATCH 07/79] block: rust: allow `hrtimer::Timer` in `RequestData` Andreas Hindborg
2026-02-15 23:34 ` [PATCH 08/79] block: rnull: add timer completion mode Andreas Hindborg
2026-02-15 23:34 ` [PATCH 09/79] block: rust: introduce `kernel::block::bio` module Andreas Hindborg
2026-02-15 23:34 ` [PATCH 10/79] block: rust: add `command` getter to `Request` Andreas Hindborg
2026-02-15 23:34 ` [PATCH 11/79] block: rust: mq: use GFP_KERNEL from prelude Andreas Hindborg
2026-02-15 23:34 ` [PATCH 12/79] block: rust: add `TagSet` flags Andreas Hindborg
2026-02-15 23:35 ` [PATCH 13/79] block: rnull: add memory backing Andreas Hindborg
2026-02-15 23:35 ` [PATCH 14/79] block: rnull: add submit queue count config option Andreas Hindborg
2026-02-15 23:35 ` [PATCH 15/79] block: rnull: add `use_per_node_hctx` " Andreas Hindborg
2026-02-15 23:35 ` [PATCH 16/79] block: rust: allow specifying home node when constructing `TagSet` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 17/79] block: rnull: allow specifying the home numa node Andreas Hindborg
2026-02-15 23:35 ` [PATCH 18/79] block: rust: add Request::sectors() method Andreas Hindborg
2026-02-15 23:35 ` [PATCH 19/79] block: rust: mq: add max_hw_discard_sectors support to GenDiskBuilder Andreas Hindborg
2026-02-15 23:35 ` [PATCH 20/79] block: rnull: add discard support Andreas Hindborg
2026-02-15 23:35 ` [PATCH 21/79] block: rust: add `NoDefaultScheduler` flag for `TagSet` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 22/79] block: rnull: add no_sched module parameter and configfs attribute Andreas Hindborg
2026-02-15 23:35 ` [PATCH 23/79] block: rust: change sector type from usize to u64 Andreas Hindborg
2026-02-15 23:35 ` [PATCH 24/79] block: rust: add `BadBlocks` for bad block tracking Andreas Hindborg
2026-02-15 23:35 ` [PATCH 25/79] block: rust: mq: add Request::end() method for custom status codes Andreas Hindborg
2026-02-15 23:35 ` [PATCH 26/79] block: rnull: add badblocks support Andreas Hindborg
2026-02-15 23:35 ` [PATCH 27/79] block: rnull: add badblocks_once support Andreas Hindborg
2026-02-15 23:35 ` [PATCH 28/79] block: rnull: add partial I/O support for bad blocks Andreas Hindborg
2026-02-15 23:35 ` [PATCH 29/79] block: rust: add `TagSet` private data support Andreas Hindborg
2026-02-15 23:35 ` [PATCH 30/79] block: rust: add `hctx` " Andreas Hindborg
2026-02-15 23:35 ` [PATCH 31/79] block: rnull: add volatile cache emulation Andreas Hindborg
2026-02-15 23:35 ` [PATCH 32/79] block: rust: implement `Sync` for `GenDisk` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 33/79] block: rust: add a back reference feature to `GenDisk` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 34/79] block: rust: introduce an idle type state for `Request` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 35/79] block: rust: add a request queue abstraction Andreas Hindborg
2026-02-15 23:35 ` [PATCH 36/79] block: rust: add a method to get the request queue for a request Andreas Hindborg
2026-02-15 23:35 ` [PATCH 37/79] block: rust: introduce `kernel::block::error` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 38/79] block: rust: require `queue_rq` to return a `BlkResult` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 39/79] block: rust: add `GenDisk::queue_data` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 40/79] block: rnull: add bandwidth limiting Andreas Hindborg
2026-02-15 23:35 ` [PATCH 41/79] block: rnull: add blocking queue mode Andreas Hindborg
2026-02-15 23:35 ` [PATCH 42/79] block: rnull: add shared tags Andreas Hindborg
2026-02-15 23:35 ` [PATCH 43/79] block: rnull: add queue depth config option Andreas Hindborg
2026-02-15 23:35 ` Andreas Hindborg [this message]
2026-02-15 23:35 ` [PATCH 45/79] block: rust: add a method to set the target sector of a request Andreas Hindborg
2026-02-15 23:35 ` [PATCH 46/79] block: rust: move gendisk vtable construction to separate function Andreas Hindborg
2026-02-15 23:35 ` [PATCH 47/79] block: rust: add zoned block device support Andreas Hindborg
2026-02-15 23:35 ` [PATCH 48/79] block: rnull: add zoned storage support Andreas Hindborg
2026-02-15 23:35 ` [PATCH 49/79] block: rust: add `map_queues` support Andreas Hindborg
2026-02-15 23:35 ` [PATCH 50/79] block: rust: add an abstraction for `struct blk_mq_queue_map` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 51/79] block: rust: add polled completion support Andreas Hindborg
2026-02-15 23:35 ` [PATCH 52/79] block: rust: add accessors to `TagSet` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 53/79] block: rnull: add polled completion support Andreas Hindborg
2026-02-15 23:35 ` [PATCH 54/79] block: rnull: add REQ_OP_FLUSH support Andreas Hindborg
2026-02-15 23:35 ` [PATCH 55/79] block: rust: add request flags abstraction Andreas Hindborg
2026-02-15 23:35 ` [PATCH 56/79] block: rust: add abstraction for block queue feature flags Andreas Hindborg
2026-02-15 23:35 ` [PATCH 57/79] block: rust: allow setting write cache and FUA flags for `GenDisk` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 58/79] block: rust: add `Segment::copy_to_page_limit` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 59/79] block: rnull: add fua support Andreas Hindborg
2026-02-15 23:35 ` [PATCH 60/79] block: fix arg type in `blk_mq_update_nr_hw_queues` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 61/79] block: rust: add `GenDisk::tag_set` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 62/79] block: rust: add `TagSet::update_hw_queue_count` Andreas Hindborg
2026-02-16 23:59   ` Ken Kurematsu
2026-02-17  9:54     ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 63/79] block: rnull: add an option to change the number of hardware queues Andreas Hindborg
2026-02-15 23:35 ` [PATCH 64/79] block: rust: add an abstraction for `struct rq_list` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 65/79] block: rust: add `queue_rqs` vtable hook Andreas Hindborg
2026-02-15 23:35 ` [PATCH 66/79] block: rnull: support queue_rqs Andreas Hindborg
2026-02-15 23:35 ` [PATCH 67/79] block: rust: remove the `is_poll` parameter from `queue_rq` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 68/79] block: rust: add a debug assert for refcounts Andreas Hindborg
2026-02-15 23:35 ` [PATCH 69/79] block: rust: add `TagSet::tag_to_rq` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 70/79] block: rust: add `Request::queue_index` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 71/79] block: rust: add `Request::requeue` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 72/79] block: rust: add `request_timeout` hook Andreas Hindborg
2026-02-15 23:36 ` [PATCH 73/79] block: rnull: add fault injection support Andreas Hindborg
2026-02-15 23:36 ` [PATCH 74/79] block: rust: add max_sectors option to `GenDiskBuilder` Andreas Hindborg
2026-02-15 23:36 ` [PATCH 75/79] block: rnull: allow configuration of the maximum IO size Andreas Hindborg
2026-02-15 23:36 ` [PATCH 76/79] block: rust: add `virt_boundary_mask` option to `GenDiskBuilder` Andreas Hindborg
2026-02-15 23:36 ` [PATCH 77/79] block: rnull: add `virt_boundary` option Andreas Hindborg
2026-02-15 23:36 ` [PATCH 78/79] block: rnull: add `shared_tag_bitmap` config option Andreas Hindborg
2026-02-15 23:36 ` [PATCH 79/79] block: rnull: add zone offline and readonly configfs files Andreas Hindborg

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