diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 7a8651921ed538780619abc622f40f8d86a2911c..a9e57f08bfa641d4cc9fb736bf2d1d4d22a6640c 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -386,6 +386,7 @@ extern struct apic *__apicdrivers[], *__apicdrivers_end[];
*/
#ifdef CONFIG_SMP
extern int wakeup_secondary_cpu_via_nmi(int apicid, unsigned long start_eip);
+extern int lapic_can_unplug_cpu(void);
#endif
#ifdef CONFIG_X86_LOCAL_APIC
diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index 9958ceea2fa3c7bd3b48571eaf9d35fb82b6afd4..1002a3e8fccc9b484de4fafd0ba6ee357c77be6c 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -25,11 +25,7 @@ extern void irq_ctx_init(int cpu);
struct irq_desc;
-#ifdef CONFIG_HOTPLUG_CPU
-#include <linux/cpumask.h>
-extern int check_irq_vectors_for_cpu_disable(void);
extern void fixup_irqs(void);
-#endif
#ifdef CONFIG_HAVE_KVM
extern void kvm_set_posted_intr_wakeup_handler(void (*handler)(void));
diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index 5e58da8efe77d7d2e7e7d222a39d624e10986ecc..14b21ca4483c5e56a18004193d69656583e117b1 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -945,7 +945,37 @@ void irq_force_complete_move(struct irq_desc *desc)
unlock:
raw_spin_unlock(&vector_lock);
}
-#endif
+
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * Note, this is not accurate accounting, but at least good enough to
+ * prevent that the actual interrupt move will run out of vectors.
+ */
+int lapic_can_unplug_cpu(void)
+{
+ unsigned int rsvd, avl, tomove, cpu = smp_processor_id();
+ int ret = 0;
+
+ raw_spin_lock(&vector_lock);
+ tomove = irq_matrix_allocated(vector_matrix);
+ avl = irq_matrix_available(vector_matrix, true);
+ if (avl < tomove) {
+ pr_warn("CPU %u has %u vectors, %u available. Cannot disable CPU\n",
+ cpu, tomove, avl);
+ ret = -ENOSPC;
+ goto out;
+ }
+ rsvd = irq_matrix_reserved(vector_matrix);
+ if (avl < rsvd) {
+ pr_warn("Reserved vectors %u > available %u. IRQ request may fail\n",
+ rsvd, avl);
+ }
+out:
+ raw_spin_unlock(&vector_lock);
+ return ret;
+}
+#endif /* HOTPLUG_CPU */
+#endif /* SMP */
static void __init print_APIC_field(int base)
{
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 188990c3a5140c214cb73c4e056075b2944e490c..49cfd9fe7589fa5ef2bef5d4a5d6431b7007836f 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -333,105 +333,6 @@ __visible void smp_kvm_posted_intr_nested_ipi(struct pt_regs *regs)
#ifdef CONFIG_HOTPLUG_CPU
-
-/* These two declarations are only used in check_irq_vectors_for_cpu_disable()
- * below, which is protected by stop_machine(). Putting them on the stack
- * results in a stack frame overflow. Dynamically allocating could result in a
- * failure so declare these two cpumasks as global.
- */
-static struct cpumask affinity_new, online_new;
-
-/*
- * This cpu is going to be removed and its vectors migrated to the remaining
- * online cpus. Check to see if there are enough vectors in the remaining cpus.
- * This function is protected by stop_machine().
- */
-int check_irq_vectors_for_cpu_disable(void)
-{
- unsigned int this_cpu, vector, this_count, count;
- struct irq_desc *desc;
- struct irq_data *data;
- int cpu;
-
- this_cpu = smp_processor_id();
- cpumask_copy(&online_new, cpu_online_mask);
- cpumask_clear_cpu(this_cpu, &online_new);
-
- this_count = 0;
- for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
- desc = __this_cpu_read(vector_irq[vector]);
- if (IS_ERR_OR_NULL(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_desc_has_action(desc) || 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 mode). In
- * this case we have two possibilities:
- *
- * 1) the resulting affinity mask is empty; that is
- * this the down'd cpu is the last cpu in the irq's
- * affinity mask, or
- *
- * 2) the resulting affinity mask is no longer a
- * subset of the online cpus but the affinity mask is
- * not zero; that is the down'd cpu is the last online
- * cpu in a user set affinity mask.
- */
- if (cpumask_empty(&affinity_new) ||
- !cpumask_subset(&affinity_new, &online_new))
- this_count++;
- }
- /* No need to check any further. */
- if (!this_count)
- return 0;
-
- count = 0;
- for_each_online_cpu(cpu) {
- if (cpu == this_cpu)
- continue;
- /*
- * We scan from FIRST_EXTERNAL_VECTOR to first system
- * 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++) {
- if (!test_bit(vector, system_vectors) &&
- IS_ERR_OR_NULL(per_cpu(vector_irq, cpu)[vector])) {
- if (++count == this_count)
- return 0;
- }
- }
- }
-
- if (count < this_count) {
- pr_warn("CPU %d disable failed: CPU has %u vectors assigned and there are only %u available.\n",
- this_cpu, this_count, count);
- return -ERANGE;
- }
- return 0;
-}
-
/* A cpu has been removed from cpu_online_mask. Reset irq affinities. */
void fixup_irqs(void)
{
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 86739f04701b6890a0cf37c61e671f983bded58b..92aadfa30d6120a989b364270289d9f1e4b35bf4 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1525,7 +1525,7 @@ int native_cpu_disable(void)
{
int ret;
- ret = check_irq_vectors_for_cpu_disable();
+ ret = lapic_can_unplug_cpu();
if (ret)
return ret;