linux-kernel - [tip:x86/apic] x86/apic: Remove the shorthand decision logic

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Date:   Thu, 25 Jul 2019 07:34:52 -0700
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     mingo@...nel.org, tglx@...utronix.de, hpa@...or.com,
        peterz@...radead.org, linux-kernel@...r.kernel.org
Subject: [tip:x86/apic] x86/apic: Remove the shorthand decision logic

Commit-ID:  1f0ad660488b8eb2450d1834af6a156104281194
Gitweb:     https://git.kernel.org/tip/1f0ad660488b8eb2450d1834af6a156104281194
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Mon, 22 Jul 2019 20:47:27 +0200
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Thu, 25 Jul 2019 16:12:02 +0200

x86/apic: Remove the shorthand decision logic

All callers of apic->send_IPI_all() and apic->send_IPI_allbutself() contain
the decision logic for shorthand invocation already and invoke
send_IPI_mask() if the prereqisites are not satisfied.

Remove the now redundant decision logic in the 32bit implementation.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://lkml.kernel.org/r/20190722105220.860244707@linutronix.de

---
 arch/x86/kernel/apic/ipi.c | 27 +++------------------------
 1 file changed, 3 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kernel/apic/ipi.c b/arch/x86/kernel/apic/ipi.c
index 117ee2323f59..71363b0d4a67 100644
--- a/arch/x86/kernel/apic/ipi.c
+++ b/arch/x86/kernel/apic/ipi.c
@@ -8,13 +8,7 @@
 DEFINE_STATIC_KEY_FALSE(apic_use_ipi_shorthand);
 
 #ifdef CONFIG_SMP
-#ifdef CONFIG_HOTPLUG_CPU
-#define DEFAULT_SEND_IPI	(1)
-#else
-#define DEFAULT_SEND_IPI	(0)
-#endif
-
-static int apic_ipi_shorthand_off __ro_after_init = DEFAULT_SEND_IPI;
+static int apic_ipi_shorthand_off __ro_after_init;
 
 static __init int apic_ipi_shorthand(char *str)
 {
@@ -293,27 +287,12 @@ void default_send_IPI_mask_logical(const struct cpumask *cpumask, int vector)
 
 void default_send_IPI_allbutself(int vector)
 {
-	/*
-	 * if there are no other CPUs in the system then we get an APIC send
-	 * error if we try to broadcast, thus avoid sending IPIs in this case.
-	 */
-	if (num_online_cpus() < 2)
-		return;
-
-	if (apic_ipi_shorthand_off || vector == NMI_VECTOR) {
-		apic->send_IPI_mask_allbutself(cpu_online_mask, vector);
-	} else {
-		__default_send_IPI_shortcut(APIC_DEST_ALLBUT, vector);
-	}
+	__default_send_IPI_shortcut(APIC_DEST_ALLBUT, vector);
 }
 
 void default_send_IPI_all(int vector)
 {
-	if (apic_ipi_shorthand_off || vector == NMI_VECTOR) {
-		apic->send_IPI_mask(cpu_online_mask, vector);
-	} else {
-		__default_send_IPI_shortcut(APIC_DEST_ALLINC, vector);
-	}
+	__default_send_IPI_shortcut(APIC_DEST_ALLINC, vector);
 }
 
 void default_send_IPI_self(int vector)