kbuild, 0day kernel build service, outputs the warning:

arch/x86/kernel/irq.c:333:1: warning: the frame size of 2056 bytes
is larger than 2048 bytes [-Wframe-larger-than=]

because check_irq_vectors_for_cpu_disable() allocates two cpumasks on the
stack.  Fix this by using cpumask_var_t, the cpumask stack safe variant.

Signed-off-by: Prarit Bhargava <pra...@redhat.com>
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Michel Lespinasse <wal...@google.com>
Cc: Seiji Aguchi <seiji.agu...@hds.com>
Cc: Yang Zhang <yang.z.zh...@intel.com>
Cc: Paul Gortmaker <paul.gortma...@windriver.com>
Cc: Janet Morgan <janet.mor...@intel.com>
Cc: Tony Luck <tony.l...@intel.com>
Cc: Ruiv Wang <ruiv.w...@gmail.com>
Cc: Gong Chen <gong.c...@linux.intel.com>
Cc: H. Peter Anvin <h...@linux.intel.com>
Cc: Gong Chen <gong.c...@linux.intel.com>
Cc: x...@kernel.org
Cc: Fengguang Wu <fengguang...@intel.com>
---
 arch/x86/kernel/irq.c |   35 +++++++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 4207e8d..b760c8d 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -269,15 +269,25 @@ EXPORT_SYMBOL_GPL(vector_used_by_percpu_irq);
  */
 int check_irq_vectors_for_cpu_disable(void)
 {
-       int irq, cpu;
+       int irq, cpu, ret = 0;
        unsigned int this_cpu, vector, this_count, count;
        struct irq_desc *desc;
        struct irq_data *data;
-       struct cpumask affinity_new, online_new;
+       cpumask_var_t affinity_new, online_new;
+
+       if (!alloc_cpumask_var(&online_new, GFP_KERNEL)){
+               ret = -ENOMEM;
+               goto out;
+       }
+
+       if (!alloc_cpumask_var(&affinity_new, GFP_KERNEL)) {
+               ret = -ENOMEM;
+               goto free_online_new;
+       }
 
        this_cpu = smp_processor_id();
-       cpumask_copy(&online_new, cpu_online_mask);
-       cpu_clear(this_cpu, online_new);
+       cpumask_copy(online_new, cpu_online_mask);
+       __cpu_clear(this_cpu, online_new);
 
        this_count = 0;
        for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
@@ -285,8 +295,8 @@ int check_irq_vectors_for_cpu_disable(void)
                if (irq >= 0) {
                        desc = irq_to_desc(irq);
                        data = irq_desc_get_irq_data(desc);
-                       cpumask_copy(&affinity_new, data->affinity);
-                       cpu_clear(this_cpu, affinity_new);
+                       cpumask_copy(affinity_new, data->affinity);
+                       __cpu_clear(this_cpu, affinity_new);
 
                        /* Do not count inactive or per-cpu irqs. */
                        if (!irq_has_action(irq) || irqd_is_per_cpu(data))
@@ -307,8 +317,8 @@ int check_irq_vectors_for_cpu_disable(void)
                         * 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))
+                       if (cpumask_empty(affinity_new) ||
+                           !cpumask_subset(affinity_new, online_new))
                                this_count++;
                }
        }
@@ -327,9 +337,14 @@ int check_irq_vectors_for_cpu_disable(void)
        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;
+               ret = -ERANGE;
        }
-       return 0;
+
+       free_cpumask_var(affinity_new);
+free_online_new:
+       free_cpumask_var(online_new);
+out:
+       return ret;
 }
 
 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
-- 
1.7.9.3

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