Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[uclinux-h8/linux.git] / arch / x86 / kernel / irq.c

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 88b3664..c7dfe1b 100644 (file)
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -347,14 +347,22 @@ int check_irq_vectors_for_cpu_disable(void)
                        if (!desc)
                                continue;
 
+                       /*
+                        * Protect against concurrent action removal,
+                        * affinity changes etc.
+                        */
+                       raw_spin_lock(&desc->lock);
                        data = irq_desc_get_irq_data(desc);
                        cpumask_copy(&affinity_new, data->affinity);
                        cpumask_clear_cpu(this_cpu, &affinity_new);
 
                        /* Do not count inactive or per-cpu irqs. */
-                       if (!irq_has_action(irq) || irqd_is_per_cpu(data))
+                       if (!irq_has_action(irq) || irqd_is_per_cpu(data)) {
+                               raw_spin_unlock(&desc->lock);
                                continue;
+                       }
 
+                       raw_spin_unlock(&desc->lock);
                        /*
                         * A single irq may be mapped to multiple
                         * cpu's vector_irq[] (for example IOAPIC cluster
@@ -385,6 +393,9 @@ int check_irq_vectors_for_cpu_disable(void)
                 * vector. If the vector is marked in the used vectors
                 * bitmap or an irq is assigned to it, we don't count
                 * it as available.
+                *
+                * As this is an inaccurate snapshot anyway, we can do
+                * this w/o holding vector_lock.
                 */
                for (vector = FIRST_EXTERNAL_VECTOR;
                     vector < first_system_vector; vector++) {
@@ -486,6 +497,11 @@ void fixup_irqs(void)
         */
        mdelay(1);
 
+       /*
+        * We can walk the vector array of this cpu without holding
+        * vector_lock because the cpu is already marked !online, so
+        * nothing else will touch it.
+        */
        for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
                unsigned int irr;
 
@@ -497,9 +513,9 @@ void fixup_irqs(void)
                        irq = __this_cpu_read(vector_irq[vector]);
 
                        desc = irq_to_desc(irq);
+                       raw_spin_lock(&desc->lock);
                        data = irq_desc_get_irq_data(desc);
                        chip = irq_data_get_irq_chip(data);
-                       raw_spin_lock(&desc->lock);
                        if (chip->irq_retrigger) {
                                chip->irq_retrigger(data);
                                __this_cpu_write(vector_irq[vector], VECTOR_RETRIGGERED);