From:   Janne Grunau <j@jannau.net>
Date:   Wed, 15 Feb 2023 12:27:13 +0100
Subject: [PATCH] arm_pmu: Invert fallback armpmu_filter() return value
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Message-Id: <20230215-arm_pmu_m1_regression-v1-1-f5a266577c8d@jannau.net>
To:     Will Deacon <will@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ravi Bangoria <ravi.bangoria@amd.com>
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        asahi@lists.linux.dev
Precedence: bulk

Fixes a regression in "perf: Rewrite core context handling" for arm_pmu
based drivers without a filter function pointer as the Apple M1 PMU.
The event is ignored if filter() returns 'true' opposite to
filter_match(). The refactoring failed to invert the return value if
arm_pmu has no filter() function pointer of its own.

Fixes: bd2756811766 ("perf: Rewrite core context handling")
Signed-off-by: Janne Grunau <j@jannau.net>
---
 drivers/perf/arm_pmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 9b593f985805..9cb22f36cf66 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -556,7 +556,7 @@ static bool armpmu_filter(struct pmu *pmu, int cpu)
 	if (ret && armpmu->filter)
 		return armpmu->filter(pmu, cpu);
 
-	return ret;
+	return !ret;
 }
 
 static ssize_t cpus_show(struct device *dev,

---
base-commit: ceaa837f96adb69c0df0397937cd74991d5d821a
change-id: 20230215-arm_pmu_m1_regression-b6dd48d0c792

Best regards,
-- 
Janne Grunau <j@jannau.net>