On Thu, Aug 01, 2024 at 12:58:45PM +0000, Alice Ryhl wrote: > This is a follow-up to the page abstractions [1] that were recently > merged in 6.11. Rust Binder will need these abstractions to manipulate > the vma in its implementation of the mmap fop on the Binder file. > > This patch is based on Wedson's implementation on the old rust branch, > but has been changed significantly. All mistakes are Alice's. > > Link: https://lore.kernel.org/r/20240528-alice-mm-v7-4-78222c31b8f4@xxxxxxxxxx [1] > Co-developed-by: Wedson Almeida Filho <wedsonaf@xxxxxxxxx> > Signed-off-by: Wedson Almeida Filho <wedsonaf@xxxxxxxxx> > Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx> > --- > Changes in v3: > - Reorder entries in mm.rs. > - Use ARef for mmput_async helper. > - Clarify that VmArea requires you to hold the mmap read or write lock. > - Link to v2: https://lore.kernel.org/r/20240727-vma-v2-1-ab3e5927dc3a@xxxxxxxxxx > > Changes in v2: > - mm.rs is redesigned from scratch making use of AsRef > - Add notes about whether destructors may sleep > - Rename Area to VmArea > - Link to v1: https://lore.kernel.org/r/20240723-vma-v1-1-32ad5a0118ee@xxxxxxxxxx > --- > rust/helpers.c | 61 +++++++++ > rust/kernel/lib.rs | 1 + > rust/kernel/mm.rs | 337 +++++++++++++++++++++++++++++++++++++++++++++++++ > rust/kernel/mm/virt.rs | 204 ++++++++++++++++++++++++++++++ > rust/kernel/types.rs | 9 ++ > 5 files changed, 612 insertions(+) > > diff --git a/rust/kernel/mm.rs b/rust/kernel/mm.rs > new file mode 100644 > index 000000000000..ed2db893fb79 > --- /dev/null > +++ b/rust/kernel/mm.rs > @@ -0,0 +1,337 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +// Copyright (C) 2024 Google LLC. > + > +//! Memory management. > +//! > +//! C header: [`include/linux/mm.h`](../../../../include/linux/mm.h) NIT: srctree > + > + /// Returns a raw pointer to the inner `mm_struct`. > + #[inline] > + pub fn as_raw(&self) -> *mut bindings::mm_struct { > + self.mm.get() > + } > + > + /// Obtain a reference from a raw pointer. > + /// > + /// # Safety > + /// > + /// The caller must ensure that `ptr` points at an `mm_struct`, and that it is not deallocated > + /// during the lifetime 'a. > + #[inline] > + pub unsafe fn from_raw_mm<'a>(ptr: *const bindings::mm_struct) -> &'a Mm { I'd just call this `from_raw`, like you call the counterpart `as_raw` above. Same goes for `MmWithUser` and `VmArea`. > diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs > index bd189d646adb..143a2bf06941 100644 > --- a/rust/kernel/types.rs > +++ b/rust/kernel/types.rs > @@ -366,6 +366,15 @@ pub unsafe fn from_raw(ptr: NonNull<T>) -> Self { > _p: PhantomData, > } > } > + > + /// Pass ownership of the refcount to a raw pointer. > + pub fn into_raw(self) -> NonNull<T> { > + let ptr = self.ptr; > + // Skip the destructor. > + core::mem::forget(self); > + > + ptr > + } I think this should be a separate patch. > } > > impl<T: AlwaysRefCounted> Clone for ARef<T> { > > --- > base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b > change-id: 20240723-vma-f80119f9fb35 > > Best regards, > -- > Alice Ryhl <aliceryhl@xxxxxxxxxx> > >
