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 <20190529161157.GA27659@redhat.com> <20190604134117.GA29963@redhat.com> <20190605155801.GA25165@redhat.com>
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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Wed, 5 Jun 2019 10:24:47 -0700
Message-ID: <CAHk-=wjkNx8u4Mcm5dfSQKYQmLQAv1Z1yGLDZvty7BVSj4eqBA@mail.gmail.com>
Subject: Re: [PATCH -mm 0/1] signal: simplify set_user_sigmask/restore_user_sigmask
To:     Oleg Nesterov <oleg@redhat.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Deepa Dinamani <deepa.kernel@gmail.com>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Davidlohr Bueso <dbueso@suse.de>, Jens Axboe <axboe@kernel.dk>,
        Davidlohr Bueso <dave@stgolabs.net>, e@80x24.org,
        Jason Baron <jbaron@akamai.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        linux-aio@kvack.org, omar.kilani@gmail.com,
        Thomas Gleixner <tglx@linutronix.de>,
        stable <stable@vger.kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        David Laight <David.Laight@aculab.com>
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On Wed, Jun 5, 2019 at 8:58 AM Oleg Nesterov <oleg@redhat.com> wrote:
>
> To simplify the review, please see the code with this patch applied.
> I am using epoll_pwait() as an example because it looks very simple.

I like it.

However.

I think I'd like it even more if we just said "we don't need
restore_saved_sigmask AT ALL".

Which would be fairly easy to do with something like the attached...

(Yes, this only does x86, which is a problem, but I'm bringing this up
as a RFC..)

Is it worth another TIF flag? This sure would simplify things, and it
really fits the concept too: this really is a do_signal() issue, and
fundamentally goes together with TIF_SIGPENDING.

                Linus

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