linux-kernel - [PATCH 06/13] perf; Simplify event_sched

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Message-Id: <20231102152018.391356347@infradead.org>
Date:   Thu, 02 Nov 2023 16:09:25 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     mingo@...nel.org
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org,
        acme@...nel.org, mark.rutland@....com,
        alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
        namhyung@...nel.org, irogers@...gle.com, adrian.hunter@...el.com
Subject: [PATCH 06/13] perf; Simplify event_sched_in()

Use guards to reduce gotos and simplify control flow.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 kernel/events/core.c |   13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1153,6 +1153,8 @@ void perf_pmu_enable(struct pmu *pmu)
 		pmu->pmu_enable(pmu);
 }
 
+DEFINE_GUARD(perf_pmu_disable, struct pmu *, perf_pmu_disable(_T), perf_pmu_enable(_T))
+
 static void perf_assert_pmu_disabled(struct pmu *pmu)
 {
 	WARN_ON_ONCE(*this_cpu_ptr(pmu->pmu_disable_count) == 0);
@@ -2489,7 +2491,6 @@ event_sched_in(struct perf_event *event,
 {
 	struct perf_event_pmu_context *epc = event->pmu_ctx;
 	struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
-	int ret = 0;
 
 	WARN_ON_ONCE(event->ctx != ctx);
 
@@ -2517,15 +2518,14 @@ event_sched_in(struct perf_event *event,
 		event->hw.interrupts = 0;
 	}
 
-	perf_pmu_disable(event->pmu);
+	guard(perf_pmu_disable)(event->pmu);
 
 	perf_log_itrace_start(event);
 
 	if (event->pmu->add(event, PERF_EF_START)) {
 		perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
 		event->oncpu = -1;
-		ret = -EAGAIN;
-		goto out;
+		return -EAGAIN;
 	}
 
 	if (!is_software_event(event))
@@ -2536,10 +2536,7 @@ event_sched_in(struct perf_event *event,
 	if (event->attr.exclusive)
 		cpc->exclusive = 1;
 
-out:
-	perf_pmu_enable(event->pmu);
-
-	return ret;
+	return 0;
 }
 
 static int