linux-kernel - [PATCH v3 01/15] perf: Remove redundant condition for AUX buffer size

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Message-ID: <20250812104018.424519320@infradead.org>
Date: Tue, 12 Aug 2025 12:38:59 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: tglx@...utronix.de
Cc: linux-kernel@...r.kernel.org,
 peterz@...radead.org,
 torvalds@...uxfoundation.org,
 mingo@...nel.org,
 namhyung@...nel.org,
 acme@...hat.com,
 kees@...nel.org,
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Subject: [PATCH v3 01/15] perf: Remove redundant condition for AUX buffer size

From: Thomas Gleixner <tglx@...utronix.de>

It is already checked whether the VMA size is the same as
nr_pages * PAGE_SIZE, so later checking both:

      aux_size == vma_size && aux_size == nr_pages * PAGE_SIZE

is redundant. Remove the vma_size check as nr_pages is what is actually
used in the allocation function. That prepares for splitting out the buffer
allocation into seperate functions, so that only nr_pages needs to be
handed in.

No functional change.

Signed-off-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://lkml.kernel.org/r/20250811070620.389961756@linutronix.de
---
 kernel/events/core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7043,7 +7043,7 @@ static int perf_mmap(struct file *file,
 		if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
 			goto aux_unlock;
 
-		if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
+		if (aux_size != nr_pages * PAGE_SIZE)
 			goto aux_unlock;
 
 		/* already mapped with a different size */