Received-SPF: pass (google.com: domain of linux-kernel+bounces-152342-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Precedence: bulk
MIME-Version: 1.0
References: <e696e720-0cd3-4505-8469-a94815b39467@I-love.SAKURA.ne.jp>
 <CAHk-=wjEZvnn51dhhLqBKUd=cuFhbYA47_OyfUOPB-0zKToL7Q@mail.gmail.com> <CAHk-=wjzqaqcicTtWfBtXyytJs1nqjJNved2JFsLVsVLYgVkuQ@mail.gmail.com>
In-Reply-To: <CAHk-=wjzqaqcicTtWfBtXyytJs1nqjJNved2JFsLVsVLYgVkuQ@mail.gmail.com>
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sat, 20 Apr 2024 11:05:35 -0700
Message-ID: <CAHk-=wjW3PdOZ7PJ+RHUKRc8SqQhcWXCACOvmwBkKUKABHKqwg@mail.gmail.com>
Subject: Re: [PATCH v2] tty: n_gsm: restrict tty devices to attach
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Jiri Slaby <jirislaby@kernel.org>, 
	Andrew Morton <akpm@linux-foundation.org>, "Starke, Daniel" <daniel.starke@siemens.com>, 
	LKML <linux-kernel@vger.kernel.org>, 
	linux-security-module <linux-security-module@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"

On Sat, 20 Apr 2024 at 11:02, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> Most other normal tty devices just expect ->write() to be called in
> normal process context, so if we do a line discipline flag, it would
                                        ^^^^^^^^^^^^^^^^^^^^
> have to be something like "I'm ok with being called with interrupts
> disabled", and then the n_gsm ->open function would just check that.

Not line discipline - it would be a 'struct tty_operations' flag
saying 'my ->write() function is ok with atomic context".

             Linus