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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri, 7 Jun 2019 11:05:13 -0700
Message-ID: <CAHk-=wjTWSra20otC3tEGrpHJL3xhUFFe0+-7bZjUpibjwKjzg@mail.gmail.com>
Subject: Re: [PATCH 1/2] select: change do_poll() to return -ERESTARTNOHAND
 rather than -EINTR
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>, Eric Wong <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 Thu, Jun 6, 2019 at 7:09 AM Oleg Nesterov <oleg@redhat.com> wrote:
>
> do_poll() returns -EINTR if interrupted and after that all its callers
> have to translate it into -ERESTARTNOHAND. Change do_poll() to return
> -ERESTARTNOHAND and update (simplify) the callers.

Ack.

The *right* return value will actually be then chosen by
poll_select_copy_remaining(), which will turn ERESTARTNOHAND to EINTR
when it can't update the timeout.

Except for the cases that use restart_block and do that instead and
don't have the whole timeout restart issue as a result.

              Linus