linux-kernel - [patch 5/6] x86/idle: Let prefer_mwait_c1_over

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Date: Thu, 29 Feb 2024 15:23:41 +0100 (CET)
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: x86@...nel.org,
 Steven Rostedt <rostedt@...dmis.org>,
 "Paul E. McKenney" <paulmck@...nel.org>
Subject: [patch 5/6] x86/idle: Let prefer_mwait_c1_over_halt() return bool

The return value is truly boolean. Make it so.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/kernel/process.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -853,21 +853,21 @@ void __noreturn stop_this_cpu(void *dumm
  * Do not prefer MWAIT if MONITOR instruction has a bug or idle=nomwait
  * is passed to kernel commandline parameter.
  */
-static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c)
+static bool prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c)
 {
 	u32 eax, ebx, ecx, edx;
 
 	/* If override is enforced on the command line, fall back to HALT. */
 	if (boot_option_idle_override != IDLE_NO_OVERRIDE)
-		return 0;
+		return false;
 
 	/* MWAIT is not supported on this platform. Fallback to HALT */
 	if (!cpu_has(c, X86_FEATURE_MWAIT))
-		return 0;
+		return false;
 
 	/* Monitor has a bug or APIC stops in C1E. Fallback to HALT */
 	if (boot_cpu_has_bug(X86_BUG_MONITOR) || boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E))
-		return 0;
+		return false;
 
 	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
 
@@ -876,13 +876,13 @@ static int prefer_mwait_c1_over_halt(con
 	 * with EAX=0, ECX=0.
 	 */
 	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED))
-		return 1;
+		return true;
 
 	/*
 	 * If MWAIT extensions are available, there should be at least one
 	 * MWAIT C1 substate present.
 	 */
-	return (edx & MWAIT_C1_SUBSTATE_MASK);
+	return !!(edx & MWAIT_C1_SUBSTATE_MASK);
 }
 
 /*