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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
commitf4cdf7ca9a1fdcca413157df19753f388a5a224e (patch)
tree60a31895b2446cd7fa27514e8c2843534a0de0da /rust/pin-init/src/alloc.rs
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Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab: - v4l2-core: added ISP statistics support and per-block validation - v4l2-core: Allow unknown HDR10 white point and luminance - New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor - New codec: Milos: VPU v2.0 codec support - isp driver: gained support for Dreamchip RPPX1 ISP framework - vsp1 driver: gained support for RZ/T2H and RZ/N2H - Novalake driver: gained CVS support for new NVL hardware - dvb-core: fix feed leak on failed DMX_ADD_PID - several driver fixes, cleanups and minor improvements * tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits) media: ipu-bridge: check all DMI entries when overriding sensor rotation media: v4l2-async: avoid deleting unlinked ASC entry on link error media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement media: intel/ipu6: fix async notifier cleanup leak on parse error media: staging/ipu7: fix async notifier UAF on probe error path media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem() media: rcar-isp: Fix VSPX reference leaks media: rcar-isp: Release ISPCORE resources media: i2c: imx415: Release runtime PM reference on VBLANK error media: i2c: imx415: Return test pattern write errors media: renesas: vsp1: Declare index variables in for loop statement media: renesas: vsp1: Make reset control optional to support platforms without a reset line media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs media: nxp: imx8-isi: Add additional 32-bit RGB format support media: nxp: imx8-isi: Add 16-bit raw Bayer format support media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks media: nxp: imx8-isi: Correct color map between V4L2 and ISI ...
Diffstat (limited to 'rust/pin-init/src/alloc.rs')
-rw-r--r--rust/pin-init/src/alloc.rs160
1 files changed, 160 insertions, 0 deletions
diff --git a/rust/pin-init/src/alloc.rs b/rust/pin-init/src/alloc.rs
new file mode 100644
index 000000000..471652e86
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+++ b/rust/pin-init/src/alloc.rs
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+#[cfg(all(feature = "alloc", not(feature = "std")))]
+use alloc::{boxed::Box, sync::Arc};
+#[cfg(feature = "alloc")]
+use core::alloc::AllocError;
+use core::{mem::MaybeUninit, pin::Pin};
+#[cfg(feature = "std")]
+use std::sync::Arc;
+
+#[cfg(not(feature = "alloc"))]
+type AllocError = core::convert::Infallible;
+
+use crate::{
+ init_from_closure, pin_init_from_closure, InPlaceWrite, Init, PinInit, ZeroableOption,
+};
+
+pub extern crate alloc;
+
+// SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee:
+// <https://doc.rust-lang.org/stable/std/option/index.html#representation>).
+unsafe impl<T> ZeroableOption for Box<T> {}
+
+/// Smart pointer that can initialize memory in-place.
+pub trait InPlaceInit<T>: Sized {
+ /// Use the given pin-initializer to pin-initialize a `T` inside of a new smart pointer of this
+ /// type.
+ ///
+ /// If `T: !Unpin` it will not be able to move afterwards.
+ fn try_pin_init<E>(init: impl PinInit<T, E>) -> Result<Pin<Self>, E>
+ where
+ E: From<AllocError>;
+
+ /// Use the given pin-initializer to pin-initialize a `T` inside of a new smart pointer of this
+ /// type.
+ ///
+ /// If `T: !Unpin` it will not be able to move afterwards.
+ #[inline]
+ fn pin_init(init: impl PinInit<T>) -> Result<Pin<Self>, AllocError> {
+ // SAFETY: We delegate to `init` and only change the error type.
+ let init = unsafe {
+ pin_init_from_closure(|slot| match init.__init(slot) {
+ Ok(()) => Ok(()),
+ Err(i) => match i {},
+ })
+ };
+ Self::try_pin_init(init)
+ }
+
+ /// Use the given initializer to in-place initialize a `T`.
+ fn try_init<E>(init: impl Init<T, E>) -> Result<Self, E>
+ where
+ E: From<AllocError>;
+
+ /// Use the given initializer to in-place initialize a `T`.
+ #[inline]
+ fn init(init: impl Init<T>) -> Result<Self, AllocError> {
+ // SAFETY: We delegate to `init` and only change the error type.
+ let init = unsafe {
+ init_from_closure(|slot| match init.__init(slot) {
+ Ok(()) => Ok(()),
+ Err(i) => match i {},
+ })
+ };
+ Self::try_init(init)
+ }
+}
+
+#[cfg(feature = "alloc")]
+macro_rules! try_new_uninit {
+ ($type:ident) => {
+ $type::try_new_uninit()?
+ };
+}
+#[cfg(all(feature = "std", not(feature = "alloc")))]
+macro_rules! try_new_uninit {
+ ($type:ident) => {
+ $type::new_uninit()
+ };
+}
+
+impl<T> InPlaceInit<T> for Box<T> {
+ #[inline]
+ fn try_pin_init<E>(init: impl PinInit<T, E>) -> Result<Pin<Self>, E>
+ where
+ E: From<AllocError>,
+ {
+ try_new_uninit!(Box).write_pin_init(init)
+ }
+
+ #[inline]
+ fn try_init<E>(init: impl Init<T, E>) -> Result<Self, E>
+ where
+ E: From<AllocError>,
+ {
+ try_new_uninit!(Box).write_init(init)
+ }
+}
+
+impl<T> InPlaceInit<T> for Arc<T> {
+ #[inline]
+ fn try_pin_init<E>(init: impl PinInit<T, E>) -> Result<Pin<Self>, E>
+ where
+ E: From<AllocError>,
+ {
+ let mut this = try_new_uninit!(Arc);
+ let Some(slot) = Arc::get_mut(&mut this) else {
+ // SAFETY: the Arc has just been created and has no external references
+ unsafe { core::hint::unreachable_unchecked() }
+ };
+ let slot = slot.as_mut_ptr();
+ // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
+ // slot is valid and will not be moved, because we pin it later.
+ unsafe { init.__init(slot)? };
+ // SAFETY: All fields have been initialized and this is the only `Arc` to that data.
+ Ok(unsafe { Pin::new_unchecked(this.assume_init()) })
+ }
+
+ #[inline]
+ fn try_init<E>(init: impl Init<T, E>) -> Result<Self, E>
+ where
+ E: From<AllocError>,
+ {
+ let mut this = try_new_uninit!(Arc);
+ let Some(slot) = Arc::get_mut(&mut this) else {
+ // SAFETY: the Arc has just been created and has no external references
+ unsafe { core::hint::unreachable_unchecked() }
+ };
+ let slot = slot.as_mut_ptr();
+ // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
+ // slot is valid.
+ unsafe { init.__init(slot)? };
+ // SAFETY: All fields have been initialized.
+ Ok(unsafe { this.assume_init() })
+ }
+}
+
+impl<T> InPlaceWrite<T> for Box<MaybeUninit<T>> {
+ type Initialized = Box<T>;
+
+ #[inline]
+ fn write_init<E>(mut self, init: impl Init<T, E>) -> Result<Self::Initialized, E> {
+ let slot = self.as_mut_ptr();
+ // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
+ // slot is valid.
+ unsafe { init.__init(slot)? };
+ // SAFETY: All fields have been initialized.
+ Ok(unsafe { self.assume_init() })
+ }
+
+ #[inline]
+ fn write_pin_init<E>(mut self, init: impl PinInit<T, E>) -> Result<Pin<Self::Initialized>, E> {
+ let slot = self.as_mut_ptr();
+ // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
+ // slot is valid and will not be moved, because we pin it later.
+ unsafe { init.__init(slot)? };
+ // SAFETY: All fields have been initialized.
+ Ok(unsafe { self.assume_init() }.into())
+ }
+}