On Thu, Aug 1, 2024 at 4:02 PM Danilo Krummrich <dakr@xxxxxxxxxx> wrote: > > 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 Ah, thanks. Good catch. > > + > > + /// 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`. I've been using this naming convention since this discussion: https://lore.kernel.org/all/20240401-marge-gepaukt-9a1972c848d9@brauner/ > > 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. Sure. Alice
