linux-kernel - [PATCH v8 10/19] arm: tegra20: cpuidle: Make abort

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Date:   Tue,  3 Dec 2019 03:41:07 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Peter De Schrijver <pdeschrijver@...dia.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     linux-pm@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v8 10/19] arm: tegra20: cpuidle: Make abort_flag atomic

Replace memory accessors with atomic API just to make code consistent
with the abort_barrier. The new variant may be even more correct now since
atomic_read() will prevent compiler from generating wrong things like
carrying abort_flag value in a register instead of re-fetching it from
memory.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 arch/arm/mach-tegra/cpuidle-tegra20.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mach-tegra/cpuidle-tegra20.c b/arch/arm/mach-tegra/cpuidle-tegra20.c
index f3a898f69a1d..3f4c75dbb4aa 100644
--- a/arch/arm/mach-tegra/cpuidle-tegra20.c
+++ b/arch/arm/mach-tegra/cpuidle-tegra20.c
@@ -32,7 +32,7 @@
 #include "sleep.h"
 
 #ifdef CONFIG_PM_SLEEP
-static bool abort_flag;
+static atomic_t abort_flag;
 static atomic_t abort_barrier;
 static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
 				    struct cpuidle_driver *drv,
@@ -167,13 +167,14 @@ static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
 	bool entered_lp2 = false;
 
 	if (tegra_pending_sgi())
-		WRITE_ONCE(abort_flag, true);
+		atomic_set(&abort_flag, 1);
 
 	cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
 
-	if (abort_flag) {
+	if (atomic_read(&abort_flag)) {
 		cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
-		abort_flag = false;	/* clean flag for next coming */
+		/* clean flag for next coming */
+		atomic_set(&abort_flag, 0);
 		return -EINTR;
 	}
 
-- 
2.24.0