Hi Lorenzo, On Wed, Oct 30, 2024 at 06:52:34PM +0000, Lorenzo Stoakes wrote: > On Mon, Oct 14, 2024 at 09:29:50AM +0000, Alice Ryhl wrote: > > The first patch introduces mm_struct and vm_area_struct abstractions, > > and the second patch uses them for miscdevice. > > > > This updates the vm_area_struct support to use the approach we discussed > > at LPC where there are three different types depending on the kind of > > access you have to the vma. You either have read access, write access, > > or you are initializing it. Each case allows a larger set of operations > > on the vma. > > > > The first patch in this series depends on vfs.rust.file for > > NotThreadSafe. The second patch in this series depends on char-misc-next > > for the base miscdevice implementation. > > > > Hi Alice, > > Just to be clear - I am very keen in seeing this land, and will take a look > a this from a VMA and locking perspective. > Thanks! > I've been tied up with other work which has delayed me, but am > simultaneously working on documenting VMA locking (with various tricky ins > and outs around 'implicit' rules) which directly feeds into ensuring the > rust abstraction correctly matches expectation on the locking side of > things. > > So I'd ideally like to get this doc update done first before reviewing, to > ensure we have good clarity on locking, but I think perhaps a good way is > for me to try to do both in conjunction with one another (will cc- you on > docs series when I send it!) > Please Cc me as well, thanks! Regards, Boqun > In any case - I will absolutely give this my attention as soon as I am able > to. > > Relatedly - we've encountered issues recently in relation to locking > subtleties so this is _highly_ pertinent and equally _highly_ motivating > for having compiler help on this + a programmatic representation in rust. > > I know Willy is in full support of this effort too, we are all keen to see > things move forward. > > Thank you for doing this! :) > > Best, Lorenzo > > > --- > > Changes in v7: > > - Make the mmap read/write lock guards respect strict owner semantics. > > - Link to v6: https://lore.kernel.org/r/20241010-vma-v6-0-d89039b6f573@xxxxxxxxxx > > > > Changes in v6: > > - Introduce VmArea{Ref,Mut,New} distinction. > > - Add a second patchset for miscdevice. > > - Rebase on char-misc-next (currently on v6.12-rc2). > > - Link to v5: https://lore.kernel.org/r/20240806-vma-v5-1-04018f05de2b@xxxxxxxxxx > > > > Changes in v5: > > - Rename VmArea::from_raw_vma to from_raw. > > - Use Pin for mutable VmArea references. > > - Go through `ARef::from` in `mmgrab_current`. > > - Link to v4: https://lore.kernel.org/r/20240802-vma-v4-1-091a87058a43@xxxxxxxxxx > > > > Changes in v4: > > - Pull out ARef::into_raw into a separate patch. > > - Update invariants and struct documentation. > > - Rename from_raw_mm to from_raw. > > - Link to v3: https://lore.kernel.org/r/20240801-vma-v3-1-db6c1c0afda9@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 > > > > --- > > Alice Ryhl (2): > > rust: mm: add abstractions for mm_struct and vm_area_struct > > rust: miscdevice: add mmap support > > > > rust/helpers/helpers.c | 1 + > > rust/helpers/mm.c | 55 +++++++ > > rust/kernel/lib.rs | 1 + > > rust/kernel/miscdevice.rs | 24 ++++ > > rust/kernel/mm.rs | 357 ++++++++++++++++++++++++++++++++++++++++++++++ > > rust/kernel/mm/virt.rs | 264 ++++++++++++++++++++++++++++++++++ > > 6 files changed, 702 insertions(+) > > --- > > base-commit: 2d424646119f28780f3963811025c05ea848b85f > > change-id: 20240723-vma-f80119f9fb35 > > > > Best regards, > > -- > > Alice Ryhl <aliceryhl@xxxxxxxxxx> > >
