From: Steven Rostedt <rostedt@goodmis.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kees Cook <kees@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
linux-hardening@vger.kernel.org,
Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>
Subject: Re: [PATCH] overflow: Introduce struct_offset() to get offset of member
Date: Fri, 28 Nov 2025 12:19:19 -0500 [thread overview]
Message-ID: <20251128121919.521ec9bf@robin> (raw)
In-Reply-To: <CAHk-=wiF9-vf3zW8vXoFGk+bo0=dSoJMm_nmVzsTDCerZzhGaw@mail.gmail.com>
On Thu, 27 Nov 2025 21:35:35 -0800
Linus Torvalds <torvalds@linux-foundation.org> wrote:
> So that 'xyz_t()' version then gets used for things where you
> explicitly state the type, and it all looks fairly obvious, eg:
>
> len = struct_size_t(struct pid, numbers, level + 1);
>
> doesn't get that "WHAA?!??!" kind of reaction.
>
> [ And so I actually think it's good that it only takes an explicit
> type - if you really have an instance, I think it's better to use just
> "struct_size(&instance, ...)" even if we _could_ easily make syntax
> like "struct_size_t(instance, ...)" work. ]
I was thinking about adding a struct_offset_t() but then I noticed that
struct_size_t() requires adding the type as it is for just getting the
size of the struct without using a variable. Whereas, I would have
preferred the struct_offset_t() to use a variable that's not a pointer
where typeof() is used.
But for my use cases, I can just add a '&' to struct_offset(), as if
struct_offset_t() were to take a type, it is no different than
offsetof().
-- Steve
prev parent reply other threads:[~2025-11-28 17:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-26 19:52 [PATCH] overflow: Introduce struct_offset() to get offset of member Steven Rostedt
2025-11-26 20:08 ` Steven Rostedt
2025-11-27 7:58 ` Kees Cook
2025-11-28 1:43 ` Steven Rostedt
2025-11-28 2:00 ` Kees Cook
2025-11-28 3:27 ` Steven Rostedt
2025-11-28 5:35 ` Linus Torvalds
2025-11-28 17:19 ` Steven Rostedt [this message]
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