From 5bb9ed6cdfeb75883652fd0ed3e3885083a92b4b Mon Sep 17 00:00:00 2001 From: Alice Ryhl Date: Tue, 8 Apr 2025 09:22:38 +0000 Subject: mm: rust: add abstraction for struct mm_struct MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Patch series "Rust support for mm_struct, vm_area_struct, and mmap", v16. This updates the vm_area_struct support to use the approach we discussed at LPC where there are several different Rust wrappers for vm_area_struct depending on the kind of access you have to the vma. Each case allows a different set of operations on the vma. This includes an MM MAINTAINERS entry as proposed by Lorenzo: https://lore.kernel.org/all/33e64b12-aa07-4e78-933a-b07c37ff1d84@lucifer.local/ This patch (of 9): These abstractions allow you to reference a `struct mm_struct` using both mmgrab and mmget refcounts. This is done using two Rust types: * Mm - represents an mm_struct where you don't know anything about the value of mm_users. * MmWithUser - represents an mm_struct where you know at compile time that mm_users is non-zero. This allows us to encode in the type system whether a method requires that mm_users is non-zero or not. For instance, you can always call `mmget_not_zero` but you can only call `mmap_read_lock` when mm_users is non-zero. The struct is called Mm to keep consistency with the C side. The ability to obtain `current->mm` is added later in this series. The mm module is defined to only exist when CONFIG_MMU is set. This avoids various errors due to missing types and functions when CONFIG_MMU is disabled. More fine-grained cfgs can be considered in the future. See the thread at [1] for more info. Link: https://lkml.kernel.org/r/20250408-vma-v16-9-d8b446e885d9@google.com Link: https://lkml.kernel.org/r/20250408-vma-v16-1-d8b446e885d9@google.com Link: https://lore.kernel.org/all/202503091916.QousmtcY-lkp@intel.com/ Signed-off-by: Alice Ryhl Acked-by: Lorenzo Stoakes Acked-by: Liam R. Howlett Acked-by: Balbir Singh Reviewed-by: Andreas Hindborg Reviewed-by: Gary Guo Cc: Alex Gaynor Cc: Arnd Bergmann Cc: Benno Lossin Cc: Björn Roy Baron Cc: Boqun Feng Cc: Greg Kroah-Hartman Cc: Jann Horn Cc: John Hubbard Cc: Matthew Wilcox (Oracle) Cc: Miguel Ojeda Cc: Suren Baghdasaryan Cc: Trevor Gross Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- rust/helpers/helpers.c | 1 + 1 file changed, 1 insertion(+) (limited to 'rust/helpers/helpers.c') diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 1e7c84df7252..0aea103c16be 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -20,6 +20,7 @@ #include "io.c" #include "jump_label.c" #include "kunit.c" +#include "mm.c" #include "mutex.c" #include "page.c" #include "platform.c" -- cgit