linux-kernel - [PATCH] arm_pmu: Mark expected switch fall-through

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Date:   Fri, 26 Jul 2019 13:27:37 +0200
From:   Anders Roxell <anders.roxell@...aro.org>
To:     will@...nel.org, mark.rutland@....com
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Anders Roxell <anders.roxell@...aro.org>
Subject: [PATCH] arm_pmu: Mark expected switch fall-through

When fall-through warnings was enabled by default the following warning
was starting to show up:

../drivers/perf/arm_pmu.c: In function ‘cpu_pm_pmu_notify’:
../drivers/perf/arm_pmu.c:726:3: warning: this statement may fall
 through [-Wimplicit-fallthrough=]
   cpu_pm_pmu_setup(armpmu, cmd);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../drivers/perf/arm_pmu.c:727:2: note: here
  case CPU_PM_ENTER_FAILED:
  ^~~~

Rework so that the compiler doesn't warn about fall-through.

Fixes: d93512ef0f0e ("Makefile: Globally enable fall-through warning")
Signed-off-by: Anders Roxell <anders.roxell@...aro.org>
---

I'm not convinced that this is the correct patch to fix this issue.
However, I can't see why we do 'armpmu->start(armpmu);' only in 'case
CPU_PM_ENTER_FAILED' and why we not call function cpu_pm_pmu_setup()
there also, since in cpu_pm_pmu_setup() has a case prepared for
CPU_PM_ENTER_FAILED.

 drivers/perf/arm_pmu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 2d06b8095a19..465a15705bab 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -724,6 +724,7 @@ static int cpu_pm_pmu_notify(struct notifier_block *b, unsigned long cmd,
 		break;
 	case CPU_PM_EXIT:
 		cpu_pm_pmu_setup(armpmu, cmd);
+		/* Fall through */
 	case CPU_PM_ENTER_FAILED:
 		armpmu->start(armpmu);
 		break;
-- 
2.20.1