linux-kernel - [tip: perf/core] perf: Use scoped_guard() for mmap_mutex in perf

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Message-ID: <175551254231.1420.3762486862116091229.tip-bot2@tip-bot2>
Date: Mon, 18 Aug 2025 10:22:22 -0000
From: "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
 "Peter Zijlstra (Intel)" <peterz@...radead.org>,
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject:
 [tip: perf/core] perf: Use scoped_guard() for mmap_mutex in perf_mmap()

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     d23a6dbc0a71741eb7b141fdc04e31360fba46ef
Gitweb:        https://git.kernel.org/tip/d23a6dbc0a71741eb7b141fdc04e31360fba46ef
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Tue, 12 Aug 2025 12:39:11 +02:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Fri, 15 Aug 2025 13:13:01 +02:00

perf: Use scoped_guard() for mmap_mutex in perf_mmap()

Mostly just re-indent noise.

Suggested-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Link: https://lore.kernel.org/r/20250812104019.838047976@infradead.org
---
 kernel/events/core.c | 35 ++++++++++++++---------------------
 1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3a5fd2b..41941df 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7146,30 +7146,23 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 	if (vma_size != PAGE_SIZE * nr_pages)
 		return -EINVAL;
 
-	mutex_lock(&event->mmap_mutex);
-	ret = -EINVAL;
+	scoped_guard (mutex, &event->mmap_mutex) {
+		/*
+		 * This relies on __pmu_detach_event() taking mmap_mutex after marking
+		 * the event REVOKED. Either we observe the state, or __pmu_detach_event()
+		 * will detach the rb created here.
+		 */
+		if (event->state <= PERF_EVENT_STATE_REVOKED)
+			return -ENODEV;
 
-	/*
-	 * This relies on __pmu_detach_event() taking mmap_mutex after marking
-	 * the event REVOKED. Either we observe the state, or __pmu_detach_event()
-	 * will detach the rb created here.
-	 */
-	if (event->state <= PERF_EVENT_STATE_REVOKED) {
-		ret = -ENODEV;
-		goto unlock;
+		if (vma->vm_pgoff == 0)
+			ret = perf_mmap_rb(vma, event, nr_pages);
+		else
+			ret = perf_mmap_aux(vma, event, nr_pages);
+		if (ret)
+			return ret;
 	}
 
-	if (vma->vm_pgoff == 0)
-		ret = perf_mmap_rb(vma, event, nr_pages);
-	else
-		ret = perf_mmap_aux(vma, event, nr_pages);
-
-unlock:
-	mutex_unlock(&event->mmap_mutex);
-
-	if (ret)
-		return ret;
-
 	/*
 	 * Since pinned accounting is per vm we cannot allow fork() to copy our
 	 * vma.