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charset=utf-8 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3826.300.87.4.3\)) Subject: Re: [PATCH v10 7/8] rust: Add read_poll_timeout functions From: Daniel Almeida In-Reply-To: <20250207132623.168854-8-fujita.tomonori@gmail.com> Date: Fri, 7 Feb 2025 22:50:37 -0300 Cc: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, netdev@vger.kernel.org, andrew@lunn.ch, hkallweit1@gmail.com, tmgross@umich.edu, ojeda@kernel.org, alex.gaynor@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, a.hindborg@samsung.com, aliceryhl@google.com, anna-maria@linutronix.de, frederic@kernel.org, tglx@linutronix.de, arnd@arndb.de, jstultz@google.com, sboyd@kernel.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, tgunders@redhat.com, me@kloenk.dev Content-Transfer-Encoding: quoted-printable Message-Id: <3F610447-C8B9-4F9D-ABDA-31989024D109@collabora.com> References: <20250207132623.168854-1-fujita.tomonori@gmail.com> <20250207132623.168854-8-fujita.tomonori@gmail.com> To: FUJITA Tomonori X-Mailer: Apple Mail (2.3826.300.87.4.3) X-ZohoMailClient: External Hi, > + > +/// Polls periodically until a condition is met or a timeout is = reached. > +/// > +/// ```rust > +/// use kernel::io::poll::read_poll_timeout; > +/// use kernel::time::Delta; > +/// use kernel::sync::{SpinLock, new_spinlock}; > +/// > +/// let lock =3D KBox::pin_init(new_spinlock!(()), = kernel::alloc::flags::GFP_KERNEL)?; > +/// let g =3D lock.lock(); > +/// read_poll_timeout(|| Ok(()), |()| true, Delta::from_micros(42), = Some(Delta::from_micros(42))); > +/// drop(g); > +/// > +/// # Ok::<(), Error>(()) IMHO, the example section here needs to be improved. > +/// ``` > +#[track_caller] > +pub fn read_poll_timeout( > + mut op: Op, > + mut cond: Cond, > + sleep_delta: Delta, > + timeout_delta: Option, > +) -> Result > +where > + Op: FnMut() -> Result, > + Cond: FnMut(&T) -> bool, > +{ > + let start =3D Instant::now(); > + let sleep =3D !sleep_delta.is_zero(); > + > + if sleep { > + might_sleep(Location::caller()); > + } > + > + loop { > + let val =3D op()?; I.e.: it=E2=80=99s not clear that `op` computes `val` until you read = this. > + if cond(&val) { It=E2=80=99s a bit unclear how `cond` works, until you see this line = here. It=E2=80=99s even more important to explain this a tad better, since it = differs slightly from the C API. Also, it doesn=E2=80=99t help that `Op` and `Cond` take and return the = unit type in the only example provided. =E2=80=94 Daniel