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From: tip-bot for Anna-Maria Gleixner <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, anna-maria@linutronix.de,
	bigeasy@linutronix.de, mingo@kernel.org, hpa@zytor.com,
	peterz@infradead.org, tglx@linutronix.de
Subject: [tip:timers/core] timerfd: Prepare for PREEMPT_RT
Date: Thu, 1 Aug 2019 09:04:53 -0700	[thread overview]
Message-ID: <tip-4da1306fb920a267b5ea21ee15cd771c7bc09cc6@git.kernel.org> (raw)
In-Reply-To: <20190730223828.600085866@linutronix.de>

Commit-ID:  4da1306fb920a267b5ea21ee15cd771c7bc09cc6
Gitweb:     https://git.kernel.org/tip/4da1306fb920a267b5ea21ee15cd771c7bc09cc6
Author:     Anna-Maria Gleixner <anna-maria@linutronix.de>
AuthorDate: Wed, 31 Jul 2019 00:33:50 +0200
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 1 Aug 2019 17:46:41 +0200

timerfd: Prepare for PREEMPT_RT

Use the hrtimer_cancel_wait_running() synchronization mechanism to prevent
priority inversion and live locks on PREEMPT_RT.

[ tglx: Split out of combo patch ]

Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190730223828.600085866@linutronix.de

---
 fs/timerfd.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/timerfd.c b/fs/timerfd.c
index 6a6fc8aa1de7..48305ba41e3c 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -471,7 +471,11 @@ static int do_timerfd_settime(int ufd, int flags,
 				break;
 		}
 		spin_unlock_irq(&ctx->wqh.lock);
-		cpu_relax();
+
+		if (isalarm(ctx))
+			hrtimer_cancel_wait_running(&ctx->t.alarm.timer);
+		else
+			hrtimer_cancel_wait_running(&ctx->t.tmr);
 	}
 
 	/*

  reply	other threads:[~2019-08-01 16:05 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-30 22:33 [patch 0/7] posix-timers: Prepare for PREEMPT_RT - part 1 Thomas Gleixner
2019-07-30 22:33 ` [patch 1/7] alarmtimer: Prepare for PREEMPT_RT Thomas Gleixner
2019-08-01 16:04   ` [tip:timers/core] " tip-bot for Anna-Maria Gleixner
2019-08-01 19:06   ` tip-bot for Anna-Maria Gleixner
2019-07-30 22:33 ` [patch 2/7] timerfd: " Thomas Gleixner
2019-08-01 16:04   ` tip-bot for Anna-Maria Gleixner [this message]
2019-08-01 19:07   ` [tip:timers/core] " tip-bot for Anna-Maria Gleixner
2019-07-30 22:33 ` [patch 3/7] itimers: " Thomas Gleixner
2019-08-01 16:05   ` [tip:timers/core] " tip-bot for Anna-Maria Gleixner
2019-08-01 19:07   ` tip-bot for Anna-Maria Gleixner
2019-07-30 22:33 ` [patch 4/7] posix-timers: Cleanup the flag/flags confusion Thomas Gleixner
2019-08-01 16:06   ` [tip:timers/core] " tip-bot for Anna-Maria Gleixner
2019-08-01 19:08   ` tip-bot for Thomas Gleixner
2019-07-30 22:33 ` [patch 5/7] posix-timers: Rework cancel retry loops Thomas Gleixner
2019-08-01 16:07   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2019-08-01 19:09   ` tip-bot for Thomas Gleixner
2019-07-30 22:33 ` [patch 6/7] posix-timers: Move rcu_head out of it union Thomas Gleixner
2019-08-01 16:08   ` [tip:timers/core] " tip-bot for Sebastian Andrzej Siewior
2019-08-01 19:09   ` tip-bot for Sebastian Andrzej Siewior
2019-07-30 22:33 ` [patch 7/7] posix-timers: Prepare for PREEMPT_RT Thomas Gleixner
2019-07-31  9:49   ` Peter Zijlstra
2019-07-31 11:03     ` Thomas Gleixner
2019-08-01 16:08   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2019-08-01 19:10   ` tip-bot for Thomas Gleixner
2019-07-31  9:49 ` [patch 0/7] posix-timers: Prepare for PREEMPT_RT - part 1 Peter Zijlstra

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