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Howlett" , "Andrew Morton" , "Greg Kroah-Hartman" , "Arnd Bergmann" , "Jann Horn" , "Suren Baghdasaryan" , "Alex Gaynor" , "Boqun Feng" , "Gary Guo" , =?utf-8?Q?Bj?= =?utf-8?Q?=C3=B6rn?= Roy Baron , "Benno Lossin" , "Trevor Gross" , , , Subject: Re: [PATCH v12 1/8] mm: rust: add abstraction for struct mm_struct In-Reply-To: <20250115-vma-v12-1-375099ae017a@google.com> (Alice Ryhl's message of "Wed, 15 Jan 2025 13:35:04 +0000") References: <20250115-vma-v12-0-375099ae017a@google.com> <20250115-vma-v12-1-375099ae017a@google.com> User-Agent: mu4e 1.12.7; emacs 29.4 Date: Mon, 20 Jan 2025 13:33:13 +0100 Message-ID: <87bjw1ekc6.fsf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 2885B2000B X-Stat-Signature: mywn68hx4xm4gi4ud7nst514osrdhhrw X-Rspam-User: X-HE-Tag: 1737381535-54795 X-HE-Meta: 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 Eg27HYH1 sG/DNkkL3oBiJBB190C0X1qg5IEOd2Fc7qcjR12S6TYAYS56CNZL253EMtVqSDKSNEnBkvRgiw+DYCdUH6U/tG2391o2ikpccLEuVLklRD9MU0+9BvP4R9W+au6/cYD1t82JvgL5xCUFTJP4CGsWwA45izWpstjHB56v/lLVR7N+2bzc/8yBL2MKBNcJlRZ6gTNlpJQSdglwKG4zudvxvqjGvHj1NUfKHrnwphP7N76FcRwTOT7pZW1IqjrCsARXgVETVsTqrSkEHsmbf/kCtPN/1AeT8TmdbKsTIK8xqqj+uwEVxz64OTDACrXduhENcC6c5exTvXvnlKbYGTKCEmmz8wgzgpjteonA7mWtPES3P/m0= X-Bogosity: Unsure, tests=bogofilter, spamicity=0.488248, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: "Alice Ryhl" writes: > 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. > > Acked-by: Lorenzo Stoakes (for mm bits) > Signed-off-by: Alice Ryhl Reviewed-by: Andreas Hindborg Best regards, Andreas Hindborg