linux-kernel - [PATCH 1/1] mm/mm_init.c: eliminate a local variable in mem_debugging_and_hardening

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Date: Mon, 18 Mar 2024 21:57:14 +0800
From: thunder.leizhen@...weicloud.com
To: Mike Rapoport <rppt@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/1] mm/mm_init.c: eliminate a local variable in mem_debugging_and_hardening_init()

From: Zhen Lei <thunder.leizhen@...wei.com>

The local variable 'page_poisoning_requested' is assigned true at only
one point. It can be eliminated by moving the code that depends on it
to the location where it is assigned true. This also make the moved
code to be compiled only if CONFIG_PAGE_POISONING is set.

Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
---
 mm/mm_init.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 549e76af8f82a8e..3eb217130bcb2b5 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -2614,7 +2614,6 @@ DEFINE_STATIC_KEY_MAYBE(CONFIG_DEBUG_VM, check_pages_enabled);
  */
 static void __init mem_debugging_and_hardening_init(void)
 {
-	bool page_poisoning_requested = false;
 	bool want_check_pages = false;
 
 #ifdef CONFIG_PAGE_POISONING
@@ -2626,18 +2625,16 @@ static void __init mem_debugging_and_hardening_init(void)
 	     (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) &&
 	      debug_pagealloc_enabled())) {
 		static_branch_enable(&_page_poisoning_enabled);
-		page_poisoning_requested = true;
 		want_check_pages = true;
-	}
-#endif
 
-	if ((_init_on_alloc_enabled_early || _init_on_free_enabled_early) &&
-	    page_poisoning_requested) {
-		pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
-			"will take precedence over init_on_alloc and init_on_free\n");
-		_init_on_alloc_enabled_early = false;
-		_init_on_free_enabled_early = false;
+		if (_init_on_alloc_enabled_early || _init_on_free_enabled_early) {
+			pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
+				"will take precedence over init_on_alloc and init_on_free\n");
+			_init_on_alloc_enabled_early = false;
+			_init_on_free_enabled_early = false;
+		}
 	}
+#endif
 
 	if (_init_on_alloc_enabled_early) {
 		want_check_pages = true;
-- 
2.34.1