linux-kernel - [tip:smp/hotplug] x86/oprofile/nmi: Remove superfluous smp_function_call

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Message-ID: <tip-9cb37ce65de7a6c645de2ab536807a4ba244c83a@git.kernel.org>
Date:   Mon, 21 Nov 2016 07:54:34 -0800
From:   tip-bot for Anna-Maria Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     rric@...nel.org, hpa@...or.com, mingo@...nel.org,
        linux-kernel@...r.kernel.org, bigeasy@...utronix.de,
        anna-maria@...utronix.de, tglx@...utronix.de
Subject: [tip:smp/hotplug] x86/oprofile/nmi: Remove superfluous
 smp_function_call_single()

Commit-ID:  9cb37ce65de7a6c645de2ab536807a4ba244c83a
Gitweb:     http://git.kernel.org/tip/9cb37ce65de7a6c645de2ab536807a4ba244c83a
Author:     Anna-Maria Gleixner <anna-maria@...utronix.de>
AuthorDate: Thu, 17 Nov 2016 19:35:39 +0100
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Mon, 21 Nov 2016 16:37:09 +0100

x86/oprofile/nmi: Remove superfluous smp_function_call_single()

Since commit 1cf4f629d9d2 ("cpu/hotplug: Move online calls to
hotplugged cpu") the CPU_ONLINE and CPU_DOWN_PREPARE notifiers are
always run on the hot plugged CPU, and as of commit 3b9d6da67e11
("cpu/hotplug: Fix rollback during error-out in __cpu_disable()")
the CPU_DOWN_FAILED notifier also runs on the hot plugged CPU.
This patch converts the SMP functional calls into direct calls.

smp_call_function_single() executes the function with interrupts
disabled. This calling convention is preserved.

Signed-off-by: Anna-Maria Gleixner <anna-maria@...utronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: Robert Richter <rric@...nel.org>
Cc: rt@...uxtronix.de
Cc: oprofile-list@...ts.sf.net
Link: http://lkml.kernel.org/r/20161117183541.8588-19-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>

---
 arch/x86/oprofile/nmi_int.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c
index 28c0412..c39172c 100644
--- a/arch/x86/oprofile/nmi_int.c
+++ b/arch/x86/oprofile/nmi_int.c
@@ -387,20 +387,24 @@ static void nmi_cpu_shutdown(void *dummy)
 	nmi_cpu_restore_registers(msrs);
 }
 
-static void nmi_cpu_up(void *dummy)
+static void nmi_cpu_up(void)
 {
+	local_irq_disable();
 	if (nmi_enabled)
-		nmi_cpu_setup(dummy);
+		nmi_cpu_setup(NULL);
 	if (ctr_running)
-		nmi_cpu_start(dummy);
+		nmi_cpu_start(NULL);
+	local_irq_enable();
 }
 
-static void nmi_cpu_down(void *dummy)
+static void nmi_cpu_down(void)
 {
+	local_irq_disable();
 	if (ctr_running)
-		nmi_cpu_stop(dummy);
+		nmi_cpu_stop(NULL);
 	if (nmi_enabled)
-		nmi_cpu_shutdown(dummy);
+		nmi_cpu_shutdown(NULL);
+	local_irq_enable();
 }
 
 static int nmi_create_files(struct dentry *root)
@@ -436,15 +440,13 @@ static int nmi_create_files(struct dentry *root)
 static int oprofile_cpu_notifier(struct notifier_block *b, unsigned long action,
 				 void *data)
 {
-	int cpu = (unsigned long)data;
-
 	switch (action & ~CPU_TASKS_FROZEN) {
 	case CPU_DOWN_FAILED:
 	case CPU_ONLINE:
-		smp_call_function_single(cpu, nmi_cpu_up, NULL, 0);
+		nmi_cpu_up();
 		break;
 	case CPU_DOWN_PREPARE:
-		smp_call_function_single(cpu, nmi_cpu_down, NULL, 1);
+		nmi_cpu_down();
 		break;
 	}
 	return NOTIFY_DONE;