x86: sparse_irq needs spin_lock in allocations

Suresh Siddha noticed that we should have a spinlock around it.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c
index 34c74cf..7ca5566 100644 (file)
--- a/arch/x86/kernel/io_apic.c
+++ b/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
        {

diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 24c83a3..d638a91 100644 (file)
--- a/kernel/irq/handle.c
+++ b/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
        {