x86: sparse_irq needs spin_lock in allocations

Suresh Siddha noticed that we should have a spinlock around it.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/io_apic.c

@@ -146,6 +146,12 @@ static void init_one_irq_cfg(struct irq_cfg *cfg)
 }
 
 static struct irq_cfg *irq_cfgx;
+
+/*
+ * Protect the irq_cfgx_free freelist:
+ */
+static DEFINE_SPINLOCK(irq_cfg_lock);
+
 #ifdef CONFIG_HAVE_SPARSE_IRQ
 static struct irq_cfg *irq_cfgx_free;
 #endif
@@ -213,8 +219,9 @@ static struct irq_cfg *irq_cfg(unsigned int irq)
 static struct irq_cfg *irq_cfg_alloc(unsigned int irq)
 {
 	struct irq_cfg *cfg, *cfg_pri;
-	int i;
+	unsigned long flags;
 	int count = 0;
+	int i;
 
 	cfg_pri = cfg = irq_cfgx;
 	while (cfg) {
@@ -226,6 +233,7 @@ static struct irq_cfg *irq_cfg_alloc(unsigned int irq)
 		count++;
 	}
 
+	spin_lock_irqsave(&irq_cfg_lock, flags);
 	if (!irq_cfgx_free) {
 		unsigned long phys;
 		unsigned long total_bytes;
@@ -263,6 +271,9 @@ static struct irq_cfg *irq_cfg_alloc(unsigned int irq)
 	else
 		irq_cfgx = cfg;
 	cfg->irq = irq;
+
+	spin_unlock_irqrestore(&irq_cfg_lock, flags);
+
 	printk(KERN_DEBUG "found new irq_cfg for irq %d\n", cfg->irq);
 #ifdef CONFIG_HAVE_SPARSE_IRQ_DEBUG
 	{

kernel/irq/handle.c

@@ -107,6 +107,11 @@ static void init_kstat_irqs(struct irq_desc *desc, int nr_desc, int nr)
 	}
 }
 
+/*
+ * Protect the sparse_irqs_free freelist:
+ */
+static DEFINE_SPINLOCK(sparse_irq_lock);
+
 #ifdef CONFIG_HAVE_SPARSE_IRQ
 static struct irq_desc *sparse_irqs_free;
 struct irq_desc *sparse_irqs;
@@ -166,11 +171,13 @@ struct irq_desc *irq_to_desc(unsigned int irq)
 	}
 	return NULL;
 }
+
 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 {
 	struct irq_desc *desc, *desc_pri;
-	int i;
+	unsigned long flags;
 	int count = 0;
+	int i;
 
 	desc_pri = desc = sparse_irqs;
 	while (desc) {
@@ -182,6 +189,7 @@ struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 		count++;
 	}
 
+	spin_lock_irqsave(&sparse_irq_lock, flags);
 	/*
 	 *  we run out of pre-allocate ones, allocate more
 	 */
@@ -223,6 +231,9 @@ struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 	else
 		sparse_irqs = desc;
 	desc->irq = irq;
+
+	spin_unlock_irqrestore(&sparse_irq_lock, flags);
+
 	printk(KERN_DEBUG "found new irq_desc for irq %d\n", desc->irq);
 #ifdef CONFIG_HAVE_SPARSE_IRQ_DEBUG
 	{