linux-kernel - [PATCH v3 29/57] perf: Simplify: __perf_install_in

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Message-ID: <20230612093539.611540686@infradead.org>
Date:   Mon, 12 Jun 2023 11:07:42 +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 29/57] perf: Simplify: __perf_install_in_context()


Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 kernel/events/core.c |   21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2732,13 +2732,13 @@ static int  __perf_install_in_context(vo
 	struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
 	struct perf_event_context *task_ctx = cpuctx->task_ctx;
 	bool reprogram = true;
-	int ret = 0;
 
-	raw_spin_lock(&cpuctx->ctx.lock);
-	if (ctx->task) {
-		raw_spin_lock(&ctx->lock);
+	if (ctx->task)
 		task_ctx = ctx;
 
+	guard(perf_ctx_lock)(cpuctx, task_ctx);
+
+	if (ctx->task) {
 		reprogram = (ctx->task == current);
 
 		/*
@@ -2748,14 +2748,10 @@ static int  __perf_install_in_context(vo
 		 * If its not running, we don't care, ctx->lock will
 		 * serialize against it becoming runnable.
 		 */
-		if (task_curr(ctx->task) && !reprogram) {
-			ret = -ESRCH;
-			goto unlock;
-		}
+		if (task_curr(ctx->task) && !reprogram)
+			return -ESRCH;
 
 		WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
-	} else if (task_ctx) {
-		raw_spin_lock(&task_ctx->lock);
 	}
 
 #ifdef CONFIG_CGROUP_PERF
@@ -2778,10 +2774,7 @@ static int  __perf_install_in_context(vo
 		add_event_to_ctx(event, ctx);
 	}
 
-unlock:
-	perf_ctx_unlock(cpuctx, task_ctx);
-
-	return ret;
+	return 0;
 }
 
 static bool exclusive_event_installable(struct perf_event *event,