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[209.85.167.182]) by smtp.gmail.com with ESMTPSA id 586e51a60fabf-41d04cf9e03sm4545853fac.14.2026.03.30.05.23.35 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 30 Mar 2026 05:23:36 -0700 (PDT) Received: by mail-oi1-f182.google.com with SMTP id 5614622812f47-467161c4ba7so2560097b6e.0 for ; Mon, 30 Mar 2026 05:23:35 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCWYUwsDZbXbEb5jbIrhwOkulwkMIw82Na/Sy/DQ+RVSN7f6BYJlofLwMuT+zPXBYuGh5phO662J8A==@kvack.org X-Received: by 2002:a05:6102:4498:b0:602:896a:84ba with SMTP id ada2fe7eead31-604e4df3704mr5271926137.17.1774873037674; Mon, 30 Mar 2026 05:17:17 -0700 (PDT) MIME-Version: 1.0 References: <20260322192159.88138-1-ojeda@kernel.org> <20260323000327.111235-1-ojeda@kernel.org> <9cf5a94c-0f37-446c-b63d-ddac5674d220@gmail.com> <641592e3-2354-4238-9eb8-a1f5c2a13126@app.fastmail.com> <93439e91-cf81-477b-b880-a813bb01ad7c@app.fastmail.com> <26d690ab-d68f-401f-ae2d-7aa4de081bce@app.fastmail.com> In-Reply-To: <26d690ab-d68f-401f-ae2d-7aa4de081bce@app.fastmail.com> From: Geert Uytterhoeven Date: Mon, 30 Mar 2026 14:17:06 +0200 X-Gmail-Original-Message-ID: X-Gm-Features: AQROBzD1En3iKQ5LsAPqOXpbj6O32MjUPo3QPwr0lgIQkMqaR2Lx1_ZSwol-K3A Message-ID: Subject: Re: [PATCH v2 0/3] Inline helpers into Rust without full LTO To: Arnd Bergmann Cc: Russell King , Christian Schrefl , Miguel Ojeda , Alice Ryhl , Ard Biesheuvel , Jamie Cunliffe , Will Deacon , Catalin Marinas , Miguel Ojeda , Andreas Hindborg , acourbot@nvidia.com, Andrew Morton , Anton Ivanov , =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= , Boqun Feng , Danilo Krummrich , David Gow , Gary Guo , Johannes Berg , Justin Stitt , linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-um@lists.infradead.org, llvm@lists.linux.dev, Benno Lossin , Mark Rutland , mmaurer@google.com, Bill Wendling , Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Nicolas Schier , Peter Zijlstra , Richard Weinberger , rust-for-linux@vger.kernel.org, Trevor Gross , "Uladzislau Rezki (Sony)" , John Paul Adrian Glaubitz Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 4F55EA0013 X-Stat-Signature: kcexd5yr7oecmmsqgmuoxg7te8knn5aa X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1774873417-335288 X-HE-Meta: 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 TphRra9w 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Arnd, On Mon, 30 Mar 2026 at 14:14, Arnd Bergmann wrote: > On Mon, Mar 30, 2026, at 14:03, Geert Uytterhoeven wrote: > > On Fri, 27 Mar 2026 at 10:02, Arnd Bergmann wrote: > >> > >> echo 'struct { short a : 3; short b :15; short c :14; } x; int y = sizeof(x);' | m68k-linux-gcc -xc - -S -o- > >> > >> this produces '4' on m68k-linux-gcc, but '6' everywhere else. I originally > >> thought this was related to this 2009 change in both compilers > > > > Oh, now I remember. AFAIK (holding wood and a rabbit leg) we don't > > have any bitfield members spanning multiple base type instances in > > the kernel. > > There are certainly very few of those, but two example I found in > UAPI are > > struct dvd_layer { > __u8 book_version : 4; > __u8 book_type : 4; > > __u8 min_rate : 4; > __u8 disc_size : 4; > > __u8 layer_type : 4; > __u8 track_path : 1; > __u8 nlayers : 2; > > __u8 track_density : 4; // crosses u8 boundary > __u8 linear_density : 4; > __u8 bca : 1; > __u32 start_sector; > __u32 end_sector; > __u32 end_sector_l0; > }; > > struct usb_raw_ep_caps { > __u32 type_control : 1; > __u32 type_iso : 1; > __u32 type_bulk : 1; > __u32 type_int : 1; > __u32 dir_in : 1; > __u32 dir_out : 1; > // 2 bit padding on m68k, 26 bits elsewhere > }; So we just need to make padding explicit? Sounds familiar ;-) Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds