linux-kernel - [RFC PATCH] x86 / hibernate: Eliminate the redundant smp_ops.play

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Message-ID: <CF154B5C3C8E7E64+20250224074357.673094-1-wangyuli@uniontech.com>
Date: Mon, 24 Feb 2025 15:43:57 +0800
From: WangYuli <wangyuli@...ontech.com>
To: rafael@...nel.org,
	pavel@...nel.org,
	tglx@...utronix.de,
	mingo@...hat.com,
	bp@...en8.de,
	dave.hansen@...ux.intel.com,
	x86@...nel.org,
	hpa@...or.com
Cc: linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	zhanjun@...ontech.com,
	niecheng1@...ontech.com,
	chenlinxuan@...ontech.com,
	WangYuli <wangyuli@...ontech.com>,
	Huacai Chen <chenhuacai@...ngson.cn>,
	Wentao Guan <guanwentao@...ontech.com>
Subject: [RFC PATCH] x86 / hibernate: Eliminate the redundant smp_ops.play_dead assignment

It's unnecessary to re-initialize smp_ops.play_dead to play_dead as
it naturally goes back to play_dead in the freshly booted kernel upon
device resume.

Suggested-by: Huacai Chen <chenhuacai@...ngson.cn>
Co-developed-by: Wentao Guan <guanwentao@...ontech.com>
Signed-off-by: Wentao Guan <guanwentao@...ontech.com>
Signed-off-by: WangYuli <wangyuli@...ontech.com>
---
 arch/x86/power/cpu.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 63230ff8cf4f..023cf9421467 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -297,9 +297,6 @@ static void __noreturn resume_play_dead(void)
 
 int hibernate_resume_nonboot_cpu_disable(void)
 {
-	void (*play_dead)(void) = smp_ops.play_dead;
-	int ret;
-
 	/*
 	 * Ensure that MONITOR/MWAIT will not be used in the "play dead" loop
 	 * during hibernate image restoration, because it is likely that the
@@ -316,13 +313,11 @@ int hibernate_resume_nonboot_cpu_disable(void)
 	 * resume) sleep afterwards, and the resumed kernel will decide itself
 	 * what to do with them.
 	 */
-	ret = cpuhp_smt_enable();
+	int ret = cpuhp_smt_enable();
 	if (ret)
 		return ret;
 	smp_ops.play_dead = resume_play_dead;
-	ret = freeze_secondary_cpus(0);
-	smp_ops.play_dead = play_dead;
-	return ret;
+	return freeze_secondary_cpus(0);
 }
 #endif
 
-- 
2.47.2