x86, irq: Protect __clear_irq_vector() with vector_lock

Function __clear_irq_vector() accesses vector related data structure,
so protect it with vector_lock. Also rename it as clear_irq_vector().

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1414397531-28254-8-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/apic/io_apic.c

@@ -1349,10 +1349,12 @@ int assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask)
 	return err;
 }
 
-static void __clear_irq_vector(int irq, struct irq_cfg *cfg)
+static void clear_irq_vector(int irq, struct irq_cfg *cfg)
 {
 	int cpu, vector;
+	unsigned long flags;
 
+	raw_spin_lock_irqsave(&vector_lock, flags);
 	BUG_ON(!cfg->vector);
 
 	vector = cfg->vector;
@@ -1362,8 +1364,11 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg)
 	cfg->vector = 0;
 	cpumask_clear(cfg->domain);
 
-	if (likely(!cfg->move_in_progress))
+	if (likely(!cfg->move_in_progress)) {
+		raw_spin_unlock_irqrestore(&vector_lock, flags);
 		return;
+	}
+
 	for_each_cpu_and(cpu, cfg->old_domain, cpu_online_mask) {
 		for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
 			if (per_cpu(vector_irq, cpu)[vector] != irq)
@@ -1373,6 +1378,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg)
 		}
 	}
 	cfg->move_in_progress = 0;
+	raw_spin_unlock_irqrestore(&vector_lock, flags);
 }
 
 void __setup_vector_irq(int cpu)
@@ -1499,7 +1505,7 @@ static void setup_ioapic_irq(unsigned int irq, struct irq_cfg *cfg,
 					 &dest)) {
 		pr_warn("Failed to obtain apicid for ioapic %d, pin %d\n",
 			mpc_ioapic_id(attr->ioapic), attr->ioapic_pin);
-		__clear_irq_vector(irq, cfg);
+		clear_irq_vector(irq, cfg);
 
 		return;
 	}
@@ -1513,7 +1519,7 @@ static void setup_ioapic_irq(unsigned int irq, struct irq_cfg *cfg,
 	if (x86_io_apic_ops.setup_entry(irq, &entry, dest, cfg->vector, attr)) {
 		pr_warn("Failed to setup ioapic entry for ioapic  %d, pin %d\n",
 			mpc_ioapic_id(attr->ioapic), attr->ioapic_pin);
-		__clear_irq_vector(irq, cfg);
+		clear_irq_vector(irq, cfg);
 
 		return;
 	}
@@ -3083,12 +3089,9 @@ int arch_setup_hwirq(unsigned int irq, int node)
 void arch_teardown_hwirq(unsigned int irq)
 {
 	struct irq_cfg *cfg = irq_cfg(irq);
-	unsigned long flags;
 
 	free_remapped_irq(irq);
-	raw_spin_lock_irqsave(&vector_lock, flags);
-	__clear_irq_vector(irq, cfg);
-	raw_spin_unlock_irqrestore(&vector_lock, flags);
+	clear_irq_vector(irq, cfg);
 	free_irq_cfg(irq, cfg);
 }