From: Peter Zijlstra <peterz@infradead.org>
Date: Tue, 12 Aug 2025 10:39:02 +0000 (+0200)
Subject: perf: Move perf_mmap_calc_limits() into both rb and aux branches
X-Git-Tag: v6.18-rc1~196^2~53
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=86a0a7c59845e7093c9c73a7115c9d86349499d1;p=thirdparty%2Flinux.git

perf: Move perf_mmap_calc_limits() into both rb and aux branches

  if (cond) {
    A;
  } else {
    B;
  }
  C;

into

  if (cond) {
    A;
    C;
  } else {
    B;
    C;
  }

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Link: https://lore.kernel.org/r/20250812104018.781244099@infradead.org
---

diff --git a/kernel/events/core.c b/kernel/events/core.c
index f90847101ade9..9f19c612c80f7 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7054,6 +7054,16 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 			ring_buffer_attach(event, NULL);
 		}
 
+		if (!perf_mmap_calc_limits(vma, &user_extra, &extra)) {
+			ret = -EPERM;
+			goto unlock;
+		}
+
+		WARN_ON(!rb && event->rb);
+
+		if (vma->vm_flags & VM_WRITE)
+			flags |= RING_BUFFER_WRITABLE;
+
 	} else {
 		/*
 		 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
@@ -7100,17 +7110,17 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 			ret = 0;
 			goto unlock;
 		}
-	}
 
-	if (!perf_mmap_calc_limits(vma, &user_extra, &extra)) {
-		ret = -EPERM;
-		goto unlock;
-	}
+		if (!perf_mmap_calc_limits(vma, &user_extra, &extra)) {
+			ret = -EPERM;
+			goto unlock;
+		}
 
-	WARN_ON(!rb && event->rb);
+		WARN_ON(!rb && event->rb);
 
-	if (vma->vm_flags & VM_WRITE)
-		flags |= RING_BUFFER_WRITABLE;
+		if (vma->vm_flags & VM_WRITE)
+			flags |= RING_BUFFER_WRITABLE;
+	}
 
 	if (!rb) {
 		rb = rb_alloc(nr_pages,