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From: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
To: Bill Wendling <morbo@google.com>
Cc: linux-kernel@vger.kernel.org, "Kees Cook" <kees@kernel.org>,
	"Qing Zhao" <qing.zhao@oracle.com>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	"Nathan Chancellor" <nathan@kernel.org>,
	"Nick Desaulniers" <nick.desaulniers+lkml@gmail.com>,
	"Justin Stitt" <justinstitt@google.com>,
	"Miguel Ojeda" <ojeda@kernel.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Heiko Carstens" <hca@linux.ibm.com>,
	"Marc Herbert" <Marc.Herbert@linux.intel.com>,
	"Uros Bizjak" <ubizjak@gmail.com>, "Tejun Heo" <tj@kernel.org>,
	"Jeff Xu" <jeffxu@chromium.org>,
	"Michal Koutný" <mkoutny@suse.com>,
	"Shakeel Butt" <shakeel.butt@linux.dev>,
	"Thomas Weißschuh" <thomas.weissschuh@linutronix.de>,
	"John Stultz" <jstultz@google.com>,
	"Christian Brauner" <brauner@kernel.org>,
	"Randy Dunlap" <rdunlap@infradead.org>,
	"Brian Gerst" <brgerst@gmail.com>,
	"Masahiro Yamada" <masahiroy@kernel.org>,
	linux-hardening@vger.kernel.org, llvm@lists.linux.dev,
	"Jan Hendrik Farr" <kernel@jfarr.cc>
Subject: Re: [PATCH v2 1/2] Compiler Attributes: Add __counted_by_ptr macro
Date: Fri, 21 Nov 2025 22:47:45 +0100	[thread overview]
Message-ID: <CANiq72=kqJApbOJ0hmC_mAYe6DO8YqXSFaLJOsbPhkXfxmvJHQ@mail.gmail.com> (raw)
In-Reply-To: <20251121195504.1661783-1-morbo@google.com>

On Fri, Nov 21, 2025 at 8:55 PM Bill Wendling <morbo@google.com> wrote:
>
> +/*
> + * Optional: only supported since clang >= 21
> + *
> + * clang: https://github.com/llvm/llvm-project/pull/137250
> + */
> +#ifdef CONFIG_CC_HAS_COUNTED_BY_FOR_POINTER
> +#define __counted_by_ptr(member)       __attribute__((__counted_by__(member)))
> +#else
> +#define __counted_by_ptr(member)
> +#endif

I guess there is a reason for this name, but it sounds to me a bit
like the thing between parenthesis is a pointer, i.e. that perhaps it
is the pointee that one that counts.

Hmm... what about `__ptr_counted_by`?

In addition, could we please provide a bit of context in the
documentation? i.e. links to the attribute docs in both Clang and GCC.

And perhaps explaining why this cannot use `__has_attribute`, i.e.
what the commit log mentions.

Thanks!

Cheers,
Miguel

  reply	other threads:[~2025-11-21 21:48 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-21 19:39 [PATCH 0/2] Add __counted_by_ptr macro Bill Wendling
2025-11-21 19:39 ` [PATCH 1/2] Compiler Attributes: " Bill Wendling
2025-11-21 19:46   ` Bill Wendling
2025-11-21 19:54   ` [PATCH v2 " Bill Wendling
2025-11-21 21:47     ` Miguel Ojeda [this message]
2025-11-24 20:01       ` Bill Wendling
2025-11-21 19:39 ` [PATCH 2/2] memblock: annotate struct memblock_type with __counted_by_ptr Bill Wendling
2025-11-22  0:30   ` Kees Cook
2025-11-22 22:16     ` Andrew Morton
2025-11-24 19:19       ` Kees Cook
2025-11-24 20:15         ` Bill Wendling
2025-11-21 23:25 ` [PATCH 0/2] Add __counted_by_ptr macro Kees Cook
2025-11-24 20:05   ` Bill Wendling

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