| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20241016035214.2229-8-fujita.tomonori@gmail.com>
Date: Wed, 16 Oct 2024 12:52:12 +0900
From: FUJITA Tomonori <fujita.tomonori@...il.com>
To: netdev@...r.kernel.org
Cc: rust-for-linux@...r.kernel.org,
andrew@...n.ch,
hkallweit1@...il.com,
tmgross@...ch.edu,
ojeda@...nel.org,
alex.gaynor@...il.com,
gary@...yguo.net,
bjorn3_gh@...tonmail.com,
benno.lossin@...ton.me,
a.hindborg@...sung.com,
aliceryhl@...gle.com,
anna-maria@...utronix.de,
frederic@...nel.org,
tglx@...utronix.de,
arnd@...db.de,
jstultz@...gle.com,
sboyd@...nel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH net-next v3 7/8] rust: Add read_poll_timeout functions
Add read_poll_timeout functions which poll periodically until a
condition is met or a timeout is reached.
C's read_poll_timeout (include/linux/iopoll.h) is a complicated macro
and a simple wrapper for Rust doesn't work. So this implements the
same functionality in Rust.
The C version uses usleep_range() while the Rust version uses
fsleep(), which uses the best sleep method so it works with spans that
usleep_range() doesn't work nicely with.
Unlike the C version, __might_sleep() is used instead of might_sleep()
to show proper debug info; the file name and line
number. might_resched() could be added to match what the C version
does but this function works without it.
For the proper debug info, readx_poll_timeout() is implemented as a
macro.
readx_poll_timeout() can only be used in a nonatomic context. This
requirement is not checked by these abstractions, but it is
intended that klint [1] or a similar tool will be used to check it
in the future.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@...il.com>
Link: https://rust-for-linux.com/klint [1]
Signed-off-by: FUJITA Tomonori <fujita.tomonori@...il.com>
---
rust/helpers/helpers.c | 1 +
rust/helpers/kernel.c | 13 +++++++
rust/kernel/error.rs | 1 +
rust/kernel/io.rs | 5 +++
rust/kernel/io/poll.rs | 84 ++++++++++++++++++++++++++++++++++++++++++
rust/kernel/lib.rs | 1 +
6 files changed, 105 insertions(+)
create mode 100644 rust/helpers/kernel.c
create mode 100644 rust/kernel/io.rs
create mode 100644 rust/kernel/io/poll.rs
diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index c274546bcf78..f9569ff1717e 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c
@@ -12,6 +12,7 @@
#include "build_assert.c"
#include "build_bug.c"
#include "err.c"
+#include "kernel.c"
#include "kunit.c"
#include "mutex.c"
#include "page.c"
diff --git a/rust/helpers/kernel.c b/rust/helpers/kernel.c
new file mode 100644
index 000000000000..da847059260b
--- /dev/null
+++ b/rust/helpers/kernel.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/kernel.h>
+
+void rust_helper_cpu_relax(void)
+{
+ cpu_relax();
+}
+
+void rust_helper___might_sleep(const char *file, int line)
+{
+ __might_sleep(file, line);
+}
diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
index 6f1587a2524e..d571b9587ed6 100644
--- a/rust/kernel/error.rs
+++ b/rust/kernel/error.rs
@@ -58,6 +58,7 @@ macro_rules! declare_err {
declare_err!(EPIPE, "Broken pipe.");
declare_err!(EDOM, "Math argument out of domain of func.");
declare_err!(ERANGE, "Math result not representable.");
+ declare_err!(ETIMEDOUT, "Connection timed out.");
declare_err!(ERESTARTSYS, "Restart the system call.");
declare_err!(ERESTARTNOINTR, "System call was interrupted by a signal and will be restarted.");
declare_err!(ERESTARTNOHAND, "Restart if no handler.");
diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs
new file mode 100644
index 000000000000..033f3c4e4adf
--- /dev/null
+++ b/rust/kernel/io.rs
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Input and Output.
+
+pub mod poll;
diff --git a/rust/kernel/io/poll.rs b/rust/kernel/io/poll.rs
new file mode 100644
index 000000000000..d4bb791f665b
--- /dev/null
+++ b/rust/kernel/io/poll.rs
@@ -0,0 +1,84 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! IO polling.
+//!
+//! C header: [`include/linux/iopoll.h`](srctree/include/linux/iopoll.h).
+
+use crate::{
+ bindings,
+ error::{code::*, Result},
+ time::{delay::fsleep, Delta, Ktime},
+};
+
+/// Polls periodically until a condition is met or a timeout is reached.
+///
+/// Public but hidden since it should only be used from public macros.
+#[doc(hidden)]
+pub fn read_poll_timeout<Op, Cond, T: Copy>(
+ mut op: Op,
+ cond: Cond,
+ sleep_delta: Delta,
+ timeout_delta: Delta,
+ sleep_before_read: bool,
+) -> Result<T>
+where
+ Op: FnMut() -> Result<T>,
+ Cond: Fn(T) -> bool,
+{
+ let timeout = Ktime::ktime_get() + timeout_delta;
+ let sleep = !sleep_delta.is_zero();
+
+ if sleep_before_read && sleep {
+ fsleep(sleep_delta);
+ }
+
+ let val = loop {
+ let val = op()?;
+ if cond(val) {
+ break val;
+ }
+ if !timeout_delta.is_zero() && Ktime::ktime_get() > timeout {
+ break op()?;
+ }
+ if sleep {
+ fsleep(sleep_delta);
+ }
+ // SAFETY: FFI call.
+ unsafe { bindings::cpu_relax() }
+ };
+
+ if cond(val) {
+ Ok(val)
+ } else {
+ Err(ETIMEDOUT)
+ }
+}
+
+/// Polls periodically until a condition is met or a timeout is reached.
+///
+/// `op` is called repeatedly until `cond` returns `true` or the timeout is
+/// reached. The return value of `op` is passed to `cond`.
+///
+/// `sleep_delta` is the duration to sleep between calls to `op`.
+/// If `sleep_delta` is less than one microsecond, the function will busy-wait.
+///
+/// `timeout_delta` is the maximum time to wait for `cond` to return `true`.
+///
+/// This macro can only be used in a nonatomic context.
+#[macro_export]
+macro_rules! readx_poll_timeout {
+ ($op:expr, $cond:expr, $sleep_delta:expr, $timeout_delta:expr) => {{
+ #[cfg(CONFIG_DEBUG_ATOMIC_SLEEP)]
+ if !$sleep_delta.is_zero() {
+ // SAFETY: FFI call.
+ unsafe {
+ $crate::bindings::__might_sleep(
+ ::core::file!().as_ptr() as *const i8,
+ ::core::line!() as i32,
+ )
+ }
+ }
+
+ $crate::io::poll::read_poll_timeout($op, $cond, $sleep_delta, $timeout_delta, false)
+ }};
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index b5f4b3ce6b48..d5fd6aeb24ca 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -35,6 +35,7 @@
#[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)]
pub mod firmware;
pub mod init;
+pub mod io;
pub mod ioctl;
#[cfg(CONFIG_KUNIT)]
pub mod kunit;
--
2.43.0
Powered by blists - more mailing lists