Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Thu, 8 Oct 2020 16:45:40 +0200
From:   Oleg Nesterov <oleg@redhat.com>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     linux-kernel@vger.kernel.org, io-uring@vger.kernel.org,
        peterz@infradead.org, tglx@linutronix.de
Subject: Re: [PATCH 3/6] kernel: split syscall restart from signal handling
Message-ID: <20201008144539.GJ9995@redhat.com>
References: <20201005150438.6628-1-axboe@kernel.dk>
 <20201005150438.6628-4-axboe@kernel.dk>
 <20201008142135.GH9995@redhat.com>
 <de00f13d-9ff0-6955-5d37-557f044ce2aa@kernel.dk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <de00f13d-9ff0-6955-5d37-557f044ce2aa@kernel.dk>
User-Agent: Mutt/1.5.24 (2015-08-30)
Precedence: bulk

On 10/08, Jens Axboe wrote:
>
> On 10/8/20 8:21 AM, Oleg Nesterov wrote:
> > 
> > Can't we avoid this patch and the and simplify the change in
> > exit_to_user_mode_loop() from the next patch? Can't the much more simple
> > patch below work?
> > 
> > Then later we can even change arch_do_signal() to accept the additional
> > argument, ti_work, so that it can use ti_work & TIF_NOTIFY_SIGNAL/SIGPENDING
> > instead of test_thread_flag/task_sigpending.
> 
> Yeah I guess that would be a bit simpler, maybe I'm too focused on
> decoupling the two. But if we go this route, and avoid sighand->lock for
> just having TIF_NOTIFY_SIGNAL set, then that should be functionally
> equivalent as far as I'm concerned.

Not sure I understand... I think that the change I propose is functionally
equivalent or I missed something.

> I'll make the reduction, I'd prefer to keep this as small/simple as
> possible initially.

Great, thanks.

Oleg.