Merge tag 'char-misc-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc/IIO/etc driver updates from Greg KH:
 "Here is the big set of char, misc, iio, counter, fpga, and other small
  driver subsystems for 7.3-rc1.

  Overall, due to some driver removals we only added a bit more code
  than removed, which was a nice change. Highlights in this merge
  request are:

   - Loads of IIO driver updates and additions

   - binder driver updates (more on that below...)

   - Removal of the SGI XP and GRU drivers as they are not used anymore
     and turn out to be pretty insecure overall

   - Removal of the obsolete ibmasm driver as it's not being used
     anymore

   - Coresight driver updates and additions

   - Mei driver udpates

   - Counter driver updates

   - FPGA driver updates

   - ICC driver updates

   - lots and lots of other tiny driver updates to resolve reported
     issues

  All of these have been in linux-next for a while"

* tag 'char-misc-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (513 commits)
  iio: chemical: atlas-sensor: use iio_trigger_poll_nested() to fix remove UAF
  iio: adc: pac1921: fix wrong channel used in trigger handler read
  iio: light: gp2ap002: re-enable irq if runtime suspend fails
  iio: light: gp2ap002: Fix unbalanced runtime PM on repeated event writes
  iio: light: apds9306: fix PM reference leak in apds9306_read_data()
  iio: gyro: mpu3050: fix sign of raw angular velocity readings
  iio: srf04: fix pm_runtime handling on probe error path
  iio: adc: ad4080: configure backend data size
  iio: adc: adi-axi-adc: add data size support for AD408X backend
  iio: chemical: atlas-sensor: fix PM reference leak in buffer postenable
  iio: dac: ad5446: fix OF module device table
  iio: light: opt4001: Fix reversed GENMASK() arguments in fault count mask
  iio: light: opt4001: Reject integration times with a non-zero seconds part
  iio: light: opt4001: Fix incompatible pointer type passed to div_u64_rem()
  iio: light: opt4001: Fix power down clearing bits of the wrong register
  iio: light: opt4060: Fix incorrect register name in threshold read error message
  iio: light: opt4060: Fix pointer type passed to div_u64_rem()
  iio: light: opt4060: Reject integration times with a non-zero seconds part
  iio: light: ltrf216a: fix runtime PM reference leak in error path
  iio: pressure: dps310: fix NULL pointer dereference on ACPI probe
  ...

1 files changed, 72 insertions, 1 deletions

diff --git a/rust/kernel/sync/poll.rs b/rust/kernel/sync/poll.rs
index 5aa0ce9ba01b..dc40bfaa57e6 100644
--- a/rust/kernel/sync/poll.rs
+++ b/rust/kernel/sync/poll.rs
@@ -5,6 +5,7 @@
 //! Utilities for working with `struct poll_table`.
 
 use crate::{
+    alloc::AllocError,
     bindings,
     fs::File,
     prelude::*,
@@ -13,8 +14,13 @@ use crate::{
         CondVar,
         LockClassKey, //
     }, //
+    types::Opaque, //
+};
+use core::{
+    marker::PhantomData,
+    mem::ManuallyDrop,
+    ops::Deref, //
 };
-use core::{marker::PhantomData, ops::Deref};
 
 /// Creates a [`PollCondVar`] initialiser with the given name and a newly-created lock class.
 #[macro_export]
@@ -70,6 +76,7 @@ impl<'a> PollTable<'a> {
 ///
 /// [`CondVar`]: crate::sync::CondVar
 #[pin_data(PinnedDrop)]
+#[repr(transparent)]
 pub struct PollCondVar {
     #[pin]
     inner: CondVar,
@@ -106,3 +113,67 @@ impl PinnedDrop for PollCondVar {
         synchronize_rcu();
     }
 }
+
+/// A [`KBox<PollCondVar>`] that uses `kfree_rcu`.
+///
+/// [`KBox<PollCondVar>`]: PollCondVar
+pub struct PollCondVarBox {
+    inner: ManuallyDrop<Pin<KBox<PollCondVarBoxInner>>>,
+}
+
+#[pin_data]
+#[repr(C)]
+struct PollCondVarBoxInner {
+    #[pin]
+    inner: PollCondVar,
+    rcu: Opaque<bindings::kvfree_rcu_head>,
+}
+
+// SAFETY: PollCondVar is Send
+unsafe impl Send for PollCondVarBoxInner {}
+// SAFETY: PollCondVar is Sync
+unsafe impl Sync for PollCondVarBoxInner {}
+
+impl PollCondVarBox {
+    /// Constructs a new boxed [`PollCondVar`].
+    pub fn new(name: &'static CStr, key: Pin<&'static LockClassKey>) -> Result<Self, AllocError> {
+        let b = KBox::pin_init(
+            pin_init!(PollCondVarBoxInner {
+                inner <- PollCondVar::new(name, key),
+                rcu: Opaque::uninit(),
+            }),
+            GFP_KERNEL,
+        )
+        .map_err(|_| AllocError)?;
+
+        Ok(PollCondVarBox {
+            inner: ManuallyDrop::new(b),
+        })
+    }
+}
+
+impl Deref for PollCondVarBox {
+    type Target = PollCondVar;
+    fn deref(&self) -> &PollCondVar {
+        &self.inner.inner
+    }
+}
+
+impl Drop for PollCondVarBox {
+    #[inline]
+    fn drop(&mut self) {
+        // SAFETY: ManuallyDrop::take ok because not already taken.
+        let boxed = unsafe { ManuallyDrop::take(&mut self.inner) };
+
+        // SAFETY: The code below frees the box without calling the actual destructor of the type,
+        // but it's okay because it re-implements the destructor using `kfree_rcu()` in place of
+        // `synchronize_rcu()`.
+        let ptr = KBox::into_raw(unsafe { Pin::into_inner_unchecked(boxed) });
+
+        // SAFETY: The pointer points at a valid `wait_queue_head`.
+        unsafe { bindings::__wake_up_pollfree((*ptr).inner.inner.wait_queue_head.get()) };
+
+        // SAFETY: This was allocated using `KBox::pin_init`, so it can be freed with `kvfree`.
+        unsafe { bindings::kvfree_call_rcu((*ptr).rcu.get(), ptr.cast::<ffi::c_void>()) };
+    }
+}