From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Dmitry Safonov <dima@arista.com>
Cc: linux-kernel@vger.kernel.org,
"Dmitry Safonov" <0x7f454c46@gmail.com>,
"Daniel Axtens" <dja@axtens.net>,
"Dmitry Vyukov" <dvyukov@google.com>,
"Michael Neuling" <mikey@neuling.org>,
"Mikulas Patocka" <mpatocka@redhat.com>,
"Nathan March" <nathan@gt.net>, "Pasi Kärkkäinen" <pasik@iki.fi>,
"Peter Hurley" <peter@hurleysoftware.com>,
"Rong, Chen" <rong.a.chen@intel.com>,
"Tan Xiaojun" <tanxiaojun@huawei.com>,
"Tetsuo Handa" <penguin-kernel@I-love.SAKURA.ne.jp>,
stable@vger.kernel.org,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Jiri Slaby" <jslaby@suse.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
"Sergey Senozhatsky" <sergey.senozhatsky.work@gmail.com>
Subject: Re: [PATCHv3 2/6] tty/ldsem: Update waiter->task before waking up reader
Date: Tue, 11 Sep 2018 14:41:29 +0900 [thread overview]
Message-ID: <20180911054129.GC4065@jagdpanzerIV> (raw)
In-Reply-To: <20180911050449.GB4065@jagdpanzerIV>
On (09/11/18 14:04), Sergey Senozhatsky wrote:
> > for (;;) {
> > set_current_state(TASK_UNINTERRUPTIBLE);
>
> I think that set_current_state() also executes memory barrier. Just
> because it accesses task state.
>
> > - if (!waiter.task)
> > + if (!READ_ONCE(waiter.task))
> > break;
> > if (!timeout)
> > break;
This READ_ONCE(waiter.task) looks interesting. Maybe could be moved
to a loop condition
while (!READ_ONCE(waiter.task)) {
...
}
-ss
next prev parent reply other threads:[~2018-09-11 5:41 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-11 1:48 [PATCHv3 0/6] tty: Hold write ldisc sem in tty_reopen() Dmitry Safonov
2018-09-11 1:48 ` [PATCHv3 1/6] tty: Drop tty->count on tty_reopen() failure Dmitry Safonov
2018-09-11 1:48 ` [PATCHv3 2/6] tty/ldsem: Update waiter->task before waking up reader Dmitry Safonov
2018-09-11 5:04 ` Sergey Senozhatsky
2018-09-11 5:41 ` Sergey Senozhatsky [this message]
2018-09-11 11:04 ` Kirill Tkhai
2018-09-11 11:44 ` Peter Zijlstra
2018-09-11 11:43 ` Peter Zijlstra
2018-09-11 11:40 ` Peter Zijlstra
2018-09-11 12:48 ` Dmitry Safonov
2018-09-11 1:48 ` [PATCHv3 3/6] tty: Hold tty_ldisc_lock() during tty_reopen() Dmitry Safonov
2018-09-11 1:48 ` [PATCHv3 4/6] tty/lockdep: Add ldisc_sem asserts Dmitry Safonov
2018-09-11 11:59 ` Peter Zijlstra
2018-09-11 12:01 ` Peter Zijlstra
2018-09-11 12:53 ` Dmitry Safonov
2018-09-11 1:48 ` [PATCHv3 5/6] tty: Simplify tty->count math in tty_reopen() Dmitry Safonov
2018-09-11 1:48 ` [PATCHv3 6/6] tty/ldsem: Decrement wait_readers on timeouted down_read() Dmitry Safonov
2018-09-11 12:02 ` Peter Zijlstra
2018-09-11 13:01 ` Dmitry Safonov
2018-09-11 13:33 ` Dmitry Safonov
2018-09-11 13:50 ` Peter Zijlstra
2018-09-11 15:04 ` Dmitry Safonov
2018-09-11 12:16 ` [PATCHv3 0/6] tty: Hold write ldisc sem in tty_reopen() Mark Rutland
2018-09-11 12:42 ` Dmitry Safonov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180911054129.GC4065@jagdpanzerIV \
--to=sergey.senozhatsky.work@gmail.com \
--cc=0x7f454c46@gmail.com \
--cc=dima@arista.com \
--cc=dja@axtens.net \
--cc=dvyukov@google.com \
--cc=gregkh@linuxfoundation.org \
--cc=jslaby@suse.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mikey@neuling.org \
--cc=mpatocka@redhat.com \
--cc=nathan@gt.net \
--cc=pasik@iki.fi \
--cc=paulmck@linux.vnet.ibm.com \
--cc=penguin-kernel@I-love.SAKURA.ne.jp \
--cc=peter@hurleysoftware.com \
--cc=peterz@infradead.org \
--cc=rong.a.chen@intel.com \
--cc=stable@vger.kernel.org \
--cc=tanxiaojun@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).