linux-kernel - [patch V3 43/60] x86/apic: Simplify X2APIC ID validation

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Message-ID: <20230801103817.514745407@linutronix.de>
Date:   Tue,  1 Aug 2023 12:47:34 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, Andrew Cooper <andrew.cooper3@...rix.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Wei Liu <wei.liu@...nel.org>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        Juergen Gross <jgross@...e.com>,
        Michael Kelley <mikelley@...rosoft.com>,
        Peter Keresztes Schmidt <peter@...esztesschmidt.de>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>
Subject: [patch V3 43/60] x86/apic: Simplify X2APIC ID validation

No point in doing the zero equals unlimited check and if not zero compare
against the real number.

Unlimited is UINT_MAX. So initialize the variable with UINT_MAX and compare
less than or equal.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/kernel/apic/x2apic_phys.c |    7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -8,7 +8,7 @@
 int x2apic_phys;
 
 static struct apic apic_x2apic_phys;
-static u32 x2apic_max_apicid __ro_after_init;
+static u32 x2apic_max_apicid __ro_after_init = UINT_MAX;
 
 void __init x2apic_set_max_apicid(u32 apicid)
 {
@@ -125,10 +125,7 @@ static int x2apic_phys_probe(void)
 /* Common x2apic functions, also used by x2apic_cluster */
 int x2apic_apic_id_valid(u32 apicid)
 {
-	if (x2apic_max_apicid && apicid > x2apic_max_apicid)
-		return 0;
-
-	return 1;
+	return apicid <= x2apic_max_apicid;
 }
 
 unsigned int x2apic_get_apic_id(unsigned long id)