regmap: Fix cache lifecycle locking and teardown

Michael Reeves <michael.reeves077@gmail.com> says:

Fix an "Invalid wait context" lockdep warning during Apple GPIO probe and
correct debugfs ordering during cache teardown.

Tested on Apple M3 MacBook Air (T8122):

- All 4 GPIO controllers probe successfully with lockdep enabled.
- The "Invalid wait context" warning no longer occurs.
- The regmap KUnit suite passes and lockdep remains enabled.

Link: https://patch.msgid.link/20261006-regcache-lifecycle-submit-v3-0-37bdd82fd47c@gmail.com

4 files changed, 38 insertions, 22 deletions

diff --git a/rust/kernel/net/netlink.rs b/rust/kernel/net/netlink.rs
index 22ef3dde36fa..2f8733a694a9 100644
--- a/rust/kernel/net/netlink.rs
+++ b/rust/kernel/net/netlink.rs
@@ -11,6 +11,7 @@
 use kernel::{
     alloc::{self, AllocError},
     error::to_result,
+    num::casts::u16_as_usize,
     prelude::*,
     transmute::AsBytes,
     types::Opaque,
@@ -86,9 +87,17 @@ impl GenlMsg {
     where
         T: ?Sized + AsBytes,
     {
+        // `nla_len` is a 16-bit field that encodes the total attribute length
+        // (header + payload). Subtracting the header size from `u16::MAX` gives
+        // the largest payload that still fits within that field.
+        const MAX_PAYLOAD_LEN: usize = u16_as_usize(u16::MAX) - size_of::<bindings::nlattr>();
+
         let skb = self.skb.skb.as_ptr();
         let len = size_of_val(value);
         let ptr = core::ptr::from_ref(value).cast::<c_void>();
+        if len > MAX_PAYLOAD_LEN {
+            return Err(EMSGSIZE);
+        }
         // SAFETY: `skb` is valid by `NetlinkSkBuff` type invariants, and the provided value is
         // readable and initialized for its `size_of` bytes.
         to_result(unsafe { bindings::nla_put(skb, attrtype, len as c_int, ptr) })
diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
index 956cda573ddb..c4e7b1d6c6f4 100644
--- a/rust/kernel/net/phy.rs
+++ b/rust/kernel/net/phy.rs
@@ -123,39 +123,37 @@ impl Device {
     /// Gets the current link state.
     ///
     /// It returns true if the link is up.
+    #[inline]
     pub fn is_link_up(&self) -> bool {
-        const LINK_IS_UP: u64 = 1;
-        // TODO: the code to access to the bit field will be replaced with automatically
-        // generated code by bindgen when it becomes possible.
-        // SAFETY: The struct invariant ensures that we may access
-        // this field without additional synchronization.
-        let bit_field = unsafe { &(*self.0.get())._bitfield_1 };
-        bit_field.get(14, 1) == LINK_IS_UP
+        let phydev = self.0.get().cast_const();
+        // SAFETY: By the type invariant of `Device`, `phydev` points to a valid
+        // `struct phy_device`, and there is no concurrent write to this field.
+        let link = unsafe { bindings::phy_device::link_raw(phydev) };
+        link == 1
     }
 
     /// Gets the current auto-negotiation configuration.
     ///
     /// It returns true if auto-negotiation is enabled.
+    #[inline]
     pub fn is_autoneg_enabled(&self) -> bool {
-        // TODO: the code to access to the bit field will be replaced with automatically
-        // generated code by bindgen when it becomes possible.
-        // SAFETY: The struct invariant ensures that we may access
-        // this field without additional synchronization.
-        let bit_field = unsafe { &(*self.0.get())._bitfield_1 };
-        bit_field.get(13, 1) == u64::from(bindings::AUTONEG_ENABLE)
+        let phydev = self.0.get().cast_const();
+        // SAFETY: By the type invariant of `Device`, `phydev` points to a valid
+        // `struct phy_device`, and there is no concurrent write to this field.
+        let autoneg = unsafe { bindings::phy_device::autoneg_raw(phydev) };
+        autoneg == bindings::AUTONEG_ENABLE
     }
 
     /// Gets the current auto-negotiation state.
     ///
     /// It returns true if auto-negotiation is completed.
+    #[inline]
     pub fn is_autoneg_completed(&self) -> bool {
-        const AUTONEG_COMPLETED: u64 = 1;
-        // TODO: the code to access to the bit field will be replaced with automatically
-        // generated code by bindgen when it becomes possible.
-        // SAFETY: The struct invariant ensures that we may access
-        // this field without additional synchronization.
-        let bit_field = unsafe { &(*self.0.get())._bitfield_1 };
-        bit_field.get(15, 1) == AUTONEG_COMPLETED
+        let phydev = self.0.get().cast_const();
+        // SAFETY: By the type invariant of `Device`, `phydev` points to a valid
+        // `struct phy_device`, and there is no concurrent write to this field.
+        let completed = unsafe { bindings::phy_device::autoneg_complete_raw(phydev) };
+        completed == 1
     }
 
     /// Sets the speed of the PHY.
diff --git a/rust/kernel/num.rs b/rust/kernel/num.rs
index dbe848e30efe..de589792a77a 100644
--- a/rust/kernel/num.rs
+++ b/rust/kernel/num.rs
@@ -15,9 +15,14 @@ pub enum Unsigned {}
 /// Designates signed primitive types.
 pub enum Signed {}
 
+mod private {
+    pub trait Sealed {}
+}
+
 /// Describes core properties of integer types.
 pub trait Integer:
-    Sized
+    private::Sealed
+    + Sized
     + Copy
     + Clone
     + PartialEq
@@ -56,6 +61,8 @@ pub trait Integer:
 macro_rules! impl_integer {
     ($($type:ty: $signedness:ty), *) => {
         $(
+        impl private::Sealed for $type {}
+
         impl Integer for $type {
             type Signedness = $signedness;
 
diff --git a/rust/kernel/pci/irq.rs b/rust/kernel/pci/irq.rs
index 6741046ec1c0..22e2cdf82a21 100644
--- a/rust/kernel/pci/irq.rs
+++ b/rust/kernel/pci/irq.rs
@@ -151,8 +151,10 @@ impl<'a> IrqVectorRegistration<'a> {
     /// [`Self::len()`].
     #[inline]
     pub fn index(&self, index: usize) -> Result<IrqVector<'_>> {
+        let index = u32::try_from(index)?;
+
         // SAFETY: `self.dev.as_raw()` is a valid pointer to a `struct pci_dev`.
-        let irq = unsafe { bindings::pci_irq_vector(self.dev.as_raw(), index as u32) };
+        let irq = unsafe { bindings::pci_irq_vector(self.dev.as_raw(), index) };
         if irq < 0 {
             return Err(Error::from_errno(irq));
         }