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Revert "FROMLIST: mm: rust: add mmput_async support"

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This reverts commit a259f04a68.

Bug: 429146594
Change-Id: Iee469177018f32b802d6be2029d389ea7ed5b261
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
This commit is contained in:
Alice Ryhl
2025-07-02 12:16:08 +00:00
parent 9248564a81
commit a121b6e72f
1 changed files with 0 additions and 49 deletions
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49
rust/kernel/mm.rs
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@@ -110,48 +110,6 @@ impl Deref for MmWithUser {
}
}
/// A wrapper for the kernel's `struct mm_struct`.
///
/// This type is identical to `MmWithUser` except that it uses `mmput_async` when dropping a
/// refcount. This means that the destructor of `ARef<MmWithUserAsync>` is safe to call in atomic
/// context.
///
/// # Invariants
///
/// Values of this type are always refcounted using `mmget`. The value of `mm_users` is non-zero.
#[repr(transparent)]
pub struct MmWithUserAsync {
mm: MmWithUser,
}
// SAFETY: It is safe to call `mmput_async` on another thread than where `mmget` was called.
unsafe impl Send for MmWithUserAsync {}
// SAFETY: All methods on `MmWithUserAsync` can be called in parallel from several threads.
unsafe impl Sync for MmWithUserAsync {}
// SAFETY: By the type invariants, this type is always refcounted.
unsafe impl AlwaysRefCounted for MmWithUserAsync {
fn inc_ref(&self) {
// SAFETY: The pointer is valid since self is a reference.
unsafe { bindings::mmget(self.as_raw()) };
}
unsafe fn dec_ref(obj: NonNull<Self>) {
// SAFETY: The caller is giving up their refcount.
unsafe { bindings::mmput_async(obj.cast().as_ptr()) };
}
}
// Make all `MmWithUser` methods available on `MmWithUserAsync`.
impl Deref for MmWithUserAsync {
type Target = MmWithUser;
#[inline]
fn deref(&self) -> &MmWithUser {
&self.mm
}
}
// These methods are safe to call even if `mm_users` is zero.
impl Mm {
/// Returns a raw pointer to the inner `mm_struct`.
@@ -203,13 +161,6 @@ impl MmWithUser {
unsafe { &*ptr.cast() }
}
/// Use `mmput_async` when dropping this refcount.
#[inline]
pub fn into_mmput_async(me: ARef<MmWithUser>) -> ARef<MmWithUserAsync> {
// SAFETY: The layouts and invariants are compatible.
unsafe { ARef::from_raw(ARef::into_raw(me).cast()) }
}
/// Attempt to access a vma using the vma read lock.
///
/// This is an optimistic trylock operation, so it may fail if there is contention. In that