linux-kernel - [PATCH v3 56/57] perf: Simplify perf_pmu_output

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Message-ID: <20230612093541.598260416@infradead.org>
Date:   Mon, 12 Jun 2023 11:08:09 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     torvalds@...ux-foundation.org, keescook@...omium.org,
        gregkh@...uxfoundation.org, pbonzini@...hat.com
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Subject: [PATCH v3 56/57] perf: Simplify perf_pmu_output_stop()


Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 kernel/events/core.c |    8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7977,7 +7977,8 @@ static void perf_pmu_output_stop(struct
 	int err, cpu;
 
 restart:
-	rcu_read_lock();
+	/* cannot have a label in front of a decl */;
+	guard(rcu)();
 	list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
 		/*
 		 * For per-CPU events, we need to make sure that neither they
@@ -7993,12 +7994,9 @@ static void perf_pmu_output_stop(struct
 			continue;
 
 		err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
-		if (err == -EAGAIN) {
-			rcu_read_unlock();
+		if (err == -EAGAIN)
 			goto restart;
-		}
 	}
-	rcu_read_unlock();
 }
 
 /*