Merge branch 'linus' into x86/apic

Pull in upstream changes to avoid conflicts

1 files changed, 18 insertions, 2 deletions

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 7ed9cba27637..bc28496fd196 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -347,15 +347,23 @@ 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,
                                      irq_data_get_affinity_mask(data));
                         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
@@ -386,6 +394,9 @@ 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++) {
@@ -487,6 +498,11 @@ 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;
 
@@ -498,9 +514,9 @@ 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);