linux-kernel - [PATCH] drivers: perf: use bitmap

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Message-ID: <20251216012004.341288-1-yury.norov@gmail.com>
Date: Mon, 15 Dec 2025 20:20:03 -0500
From: "Yury Norov (NVIDIA)" <yury.norov@...il.com>
To: Atish Patra <atish.patra@...ux.dev>,
	Anup Patel <anup@...infault.org>,
	Will Deacon <will@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Paul Walmsley <pjw@...nel.org>,
	Palmer Dabbelt <palmer@...belt.com>,
	Albert Ou <aou@...s.berkeley.edu>,
	Alexandre Ghiti <alex@...ti.fr>,
	Ji Sheng Teoh <jisheng.teoh@...rfivetech.com>,
	linux-riscv@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-perf-users@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: "Yury Norov (NVIDIA)" <yury.norov@...il.com>
Subject: [PATCH] drivers: perf: use bitmap_empty() where appropriate

bitmap_empty() is more verbose and efficient, as it stops traversing
bitmaps as soon as the 1st set bit found.

Switch perf code to using bitmap_empty() where appropriate, and
correspondingly use boolean types.

Signed-off-by: Yury Norov (NVIDIA) <yury.norov@...il.com>
---
 drivers/perf/riscv_pmu_sbi.c         | 2 +-
 drivers/perf/starfive_starlink_pmu.c | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 7dd282da67ce..9dcc22fd48ef 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -1244,7 +1244,7 @@ static int riscv_pm_pmu_notify(struct notifier_block *b, unsigned long cmd,
 {
 	struct riscv_pmu *rvpmu = container_of(b, struct riscv_pmu, riscv_pm_nb);
 	struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
-	int enabled = bitmap_weight(cpuc->used_hw_ctrs, RISCV_MAX_COUNTERS);
+	bool enabled = !bitmap_empty(cpuc->used_hw_ctrs, RISCV_MAX_COUNTERS);
 	struct perf_event *event;
 	int idx;
 
diff --git a/drivers/perf/starfive_starlink_pmu.c b/drivers/perf/starfive_starlink_pmu.c
index 5e5a672b4229..964897c2baa9 100644
--- a/drivers/perf/starfive_starlink_pmu.c
+++ b/drivers/perf/starfive_starlink_pmu.c
@@ -450,8 +450,7 @@ static int starlink_pmu_pm_notify(struct notifier_block *b,
 							 starlink_pmu_pm_nb);
 	struct starlink_hw_events *hw_events =
 					this_cpu_ptr(starlink_pmu->hw_events);
-	int enabled = bitmap_weight(hw_events->used_mask,
-				    STARLINK_PMU_MAX_COUNTERS);
+	bool enabled = !bitmap_empty(hw_events->used_mask, STARLINK_PMU_MAX_COUNTERS);
 	struct perf_event *event;
 	int idx;
 
-- 
2.43.0