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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Preeti U Murthy <preeti@linux.vnet.ibm.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Marcelo Tosatti <mtosatt@redhat.com>,
	Frederic Weisbecker <fweisbec@gmail.com>
Subject: [patch 34/39] tick: broadcast-hrtimer: Remove overly clever return value abuse
Date: Tue, 14 Apr 2015 21:09:22 -0000
Message-ID: <20150414203503.404751457@linutronix.de> (raw)
In-Reply-To: <20150414203303.702062272@linutronix.de>


[-- Attachment #0: tick-broadcast-hrtimer-remove-overly-clever-return-value-abuse.patch --]
[-- Type: text/plain, Size: 1306 bytes --]

The assignment of bc_moved in the conditional construct relies on the
fact that in the case of hrtimer_start() invocation the return value
is always 0. It took me a while to understand it.

We want to get rid of the hrtimer_start() return value. Open code the
logic which makes it readable as well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc:  Preeti U Murthy <preeti@linux.vnet.ibm.com>
---
 kernel/time/tick-broadcast-hrtimer.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

Index: tip/kernel/time/tick-broadcast-hrtimer.c
===================================================================
--- tip.orig/kernel/time/tick-broadcast-hrtimer.c
+++ tip/kernel/time/tick-broadcast-hrtimer.c
@@ -66,9 +66,11 @@ static int bc_set_next(ktime_t expires,
 	 * hrtimer_{start/cancel} functions call into tracing,
 	 * calls to these functions must be bound within RCU_NONIDLE.
 	 */
-	RCU_NONIDLE(bc_moved = (hrtimer_try_to_cancel(&bctimer) >= 0) ?
-		!hrtimer_start(&bctimer, expires, HRTIMER_MODE_ABS_PINNED) :
-			0);
+	RCU_NONIDLE({
+			bc_moved = hrtimer_try_to_cancel(&bctimer) >= 0;
+			if (bc_moved)
+				hrtimer_start(&bctimer, expires,
+					      HRTIMER_MODE_ABS_PINNED);});
 	if (bc_moved) {
 		/* Bind the "device" to the cpu */
 		bc->bound_on = smp_processor_id();



  parent reply index

Thread overview: 123+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-14 21:08 [patch 00/39] hrtimer/tick: Optimizations, cleanups and solutions for various issues Thomas Gleixner
2015-04-14 21:08 ` [patch 01/39] hrtimer: Update active_bases before calling hrtimer_force_reprogram() Thomas Gleixner
2015-04-14 21:08 ` [patch 02/39] hrtimer: Get rid of the resolution field in hrtimer_clock_base Thomas Gleixner
2015-04-15  6:29   ` Frans Klaver
2015-04-15  6:32     ` Frans Klaver
2015-04-20  8:34   ` Preeti U Murthy
2015-04-22 19:05   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 03/39] net: sched: Use hrtimer_resolution instead of hrtimer_get_res() Thomas Gleixner
2015-04-16 16:04   ` David Miller
2015-04-22 19:05   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 04/39] sound: " Thomas Gleixner
2015-04-16  8:07   ` Takashi Iwai
2015-04-16  9:08     ` Thomas Gleixner
2015-04-22 19:05   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 05/39] hrtimer: Get rid " Thomas Gleixner
2015-04-22 19:05   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 06/39] hrtimer: Make the statistics fields smaller Thomas Gleixner
2015-04-22 19:06   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 07/39] hrtimer: Get rid of softirq time Thomas Gleixner
2015-04-22 19:06   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 08/39] hrtimer: Make offset update smarter Thomas Gleixner
2015-04-20  9:30   ` Preeti U Murthy
2015-04-22 19:06   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 09/39] hrtimer: Use a bits for various boolean indicators Thomas Gleixner
2015-04-22 19:07   ` [tip:timers/core] hrtimer: Use " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 10/39] hrtimer: Use cpu_base->active_base for hotpath iterators Thomas Gleixner
2015-04-20 11:16   ` Preeti U Murthy
2015-04-21 11:53     ` Thomas Gleixner
2015-04-22  3:13       ` Preeti U Murthy
2015-04-22 19:07   ` [tip:timers/core] hrtimer: Use cpu_base-> active_base " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 11/39] hrtimer: Cache line align the hrtimer cpu base Thomas Gleixner
2015-04-22 19:07   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 12/39] hrtimer: Align the hrtimer clock bases as well Thomas Gleixner
2015-04-22 19:07   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 13/39] timerqueue: Let timerqueue_add/del return information Thomas Gleixner
2015-04-22 19:08   ` [tip:timers/core] timerqueue: Let timerqueue_add/ del " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 14/39] hrtimer: Make use of timerqueue_add/del return values Thomas Gleixner
2015-04-22 19:08   ` [tip:timers/core] hrtimer: Make use of timerqueue_add/ del " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 15/39] hrtimer: Keep pointer to first timer and simplify __remove_hrtimer() Thomas Gleixner
2015-04-22 19:08   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 16/39] hrtimer: Get rid of hrtimer softirq Thomas Gleixner
2015-04-22 19:09   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 17/39] tick: sched: Remove hrtimer_active() checks Thomas Gleixner
2015-04-16 13:37   ` Frederic Weisbecker
2015-04-22 19:09   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 18/39] tick: sched: Force tick interrupt and get rid of softirq magic Thomas Gleixner
2015-04-22 14:22   ` Frederic Weisbecker
2015-04-22 14:32     ` Thomas Gleixner
2015-04-23 11:47       ` Frederic Weisbecker
2015-04-23 13:07         ` Thomas Gleixner
2015-04-23 16:14           ` Frederic Weisbecker
2015-04-22 19:09   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 19/39] tick: sched: Restructure code Thomas Gleixner
2015-04-22 19:09   ` [tip:timers/core] tick: Sched: " tip-bot for Thomas Gleixner
2015-04-14 21:08 ` [patch 20/39] tick: nohz: Rework next timer evaluation Thomas Gleixner
2015-04-16 16:42   ` Paul E. McKenney
2015-04-21 12:04     ` Thomas Gleixner
2015-04-22 19:10   ` [tip:timers/core] tick: Nohz: " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 21/39] x86: perf: Use hrtimer_start() Thomas Gleixner
2015-04-22 19:10   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 22/39] x86: perf: uncore: " Thomas Gleixner
2015-04-22 19:10   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 23/39] perf: core: " Thomas Gleixner
2015-04-22 19:11   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 24/39] sched: core: Use hrtimer_start[_expires]() Thomas Gleixner
2015-04-22 19:11   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 25/39] sched: deadline: Use hrtimer_start() Thomas Gleixner
2015-04-22 19:11   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 26/39] hrtimer: Get rid of __hrtimer_start_range_ns() Thomas Gleixner
2015-04-22 19:11   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 27/39] hrtimer: Make hrtimer_start() a inline wrapper Thomas Gleixner
2015-04-22 19:12   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 28/39] hrtimer: Remove bogus hrtimer_active() check Thomas Gleixner
2015-04-22 19:12   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 29/39] hrtimer: Rmove " Thomas Gleixner
2015-04-22 19:12   ` [tip:timers/core] futex: Remove " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 30/39] rtmutex: " Thomas Gleixner
2015-04-22 19:13   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 31/39] net: core: pktgen: " Thomas Gleixner
2015-04-16 16:04   ` David Miller
2015-04-22 19:13   ` [tip:timers/core] net: core: pktgen: Remove bogus hrtimer_active( ) check tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 32/39] alarmtimer: Get rid of unused return value Thomas Gleixner
2015-04-22 19:13   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` Thomas Gleixner [this message]
2015-04-17 10:33   ` [patch 34/39] tick: broadcast-hrtimer: Remove overly clever return value abuse Preeti U Murthy
2015-04-22 19:13   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 35/39] hrtimer: Remove hrtimer_start() return value Thomas Gleixner
2015-04-22 19:14   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 36/39] hrtimer: Avoid locking in hrtimer_cancel() if timer not active Thomas Gleixner
2015-04-22 19:14   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 37/39] staging: ozwpan: Remove hrtimer_active() check Thomas Gleixner
2015-04-14 21:09 ` [patch 38/39] timer: Remove pointless return value of do_usleep_range() Thomas Gleixner
2015-04-22 19:14   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2015-04-14 21:09 ` [patch 39/39] timer: Put usleep_range into the __sched section Thomas Gleixner
2015-04-22 19:14   ` [tip:timers/core] " tip-bot for Thomas Gleixner
     [not found] ` <20150414203503.322172417@linutronix.de>
2015-04-14 21:38   ` [patch 33/39] power: reset: ltc2952: Remove bogus hrtimer_start() return value checks Frans Klaver
2015-04-30 15:49   ` Sebastian Reichel
  -- strict thread matches above, loose matches on Subject: below --
2015-04-07  2:10 [PATCH V2 0/2] hrtimer: Iterate only over active clock-bases Viresh Kumar
2015-04-07  2:10 ` [PATCH V2 1/2] hrtimer: update '->active_bases' before calling hrtimer_force_reprogram() Viresh Kumar
2015-04-22 19:04   ` [tip:timers/core] hrtimer: Update active_bases " tip-bot for Viresh Kumar
2015-04-07  2:10 ` [PATCH V2 2/2] hrtimer: Iterate only over active clock-bases Viresh Kumar
2015-04-08 12:10   ` Peter Zijlstra
2015-04-08 20:11   ` Thomas Gleixner
2015-04-09  2:42     ` Viresh Kumar
2015-04-09  6:28     ` [PATCH] hrtimer: Replace cpu_base->active_bases with a direct check of the active list Ingo Molnar
2015-04-09  6:38       ` Ingo Molnar
2015-04-09  6:39         ` [PATCH] hrtimer: Only iterate over active bases in migrate_hrtimers() Ingo Molnar
2015-04-09  6:53         ` [PATCH] hrtimer: Replace timerqueue_getnext() uses with direct access to 'active.next' Ingo Molnar
2015-04-09  7:10         ` [PATCH] hrtimers: Use consistent variable names for timerqueue_node iterations Ingo Molnar
2015-04-09  6:57       ` [PATCH] hrtimer: Replace cpu_base->active_bases with a direct check of the active list Peter Zijlstra
2015-04-09  7:09         ` Ingo Molnar
2015-04-09  7:20           ` Ingo Molnar
2015-04-09  8:58             ` Thomas Gleixner
2015-04-09  8:58             ` Peter Zijlstra
2015-04-09  9:18               ` Thomas Gleixner
2015-04-09  9:31                 ` Peter Zijlstra
2015-04-09  9:56                   ` Thomas Gleixner
2015-04-13  5:53                 ` Preeti U Murthy
2015-04-13  7:53                   ` Thomas Gleixner
2015-04-09  8:03           ` Peter Zijlstra
2015-04-09  8:10             ` Ingo Molnar
2015-04-09  8:53       ` Thomas Gleixner
2015-04-09  9:18         ` Ingo Molnar

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