kernel/smp.c: remove cpumask_ipi

After commit 9a46ad6d6df3 ("smp: make smp_call_function_many() use logic
similar to smp_call_function_single()"), cfd->cpumask is accessed only
in smp_call_function_many().  So there is no more need to copy it into
cfd->cpumask_ipi before putting csd into the list.  The cpumask_ipi
field is obsolete and can be removed.

Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Wang YanQing <udknight@gmail.com>
Cc: Xie XiuQi <xiexiuqi@huawei.com>
Cc: Shaohua Li <shli@fusionio.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/smp.c b/kernel/smp.c
index 4ad913e7c253b3cbdc55c685319e8324f7d564db..ffee35bef1793107c33c31d7845e4b9c5e9e43d9 100644 (file)
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -23,7 +23,6 @@ enum {
 struct call_function_data {
        struct call_single_data __percpu *csd;
        cpumask_var_t           cpumask;
-       cpumask_var_t           cpumask_ipi;
 };
 
 static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_function_data, cfd_data);
@@ -42,14 +41,8 @@ hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu)
                if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL,
                                cpu_to_node(cpu)))
                        return notifier_from_errno(-ENOMEM);
-               if (!zalloc_cpumask_var_node(&cfd->cpumask_ipi, GFP_KERNEL,
-                               cpu_to_node(cpu))) {
-                       free_cpumask_var(cfd->cpumask);
-                       return notifier_from_errno(-ENOMEM);
-               }
                cfd->csd = alloc_percpu(struct call_single_data);
                if (!cfd->csd) {
-                       free_cpumask_var(cfd->cpumask_ipi);
                        free_cpumask_var(cfd->cpumask);
                        return notifier_from_errno(-ENOMEM);
                }
@@ -62,7 +55,6 @@ hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu)
        case CPU_DEAD:
        case CPU_DEAD_FROZEN:
                free_cpumask_var(cfd->cpumask);
-               free_cpumask_var(cfd->cpumask_ipi);
                free_percpu(cfd->csd);
                break;
 #endif
@@ -383,13 +375,6 @@ void smp_call_function_many(const struct cpumask *mask,
        if (unlikely(!cpumask_weight(cfd->cpumask)))
                return;
 
-       /*
-        * After we put an entry into the list, cfd->cpumask may be cleared
-        * again when another CPU sends another IPI for a SMP function call, so
-        * cfd->cpumask will be zero.
-        */
-       cpumask_copy(cfd->cpumask_ipi, cfd->cpumask);
-
        for_each_cpu(cpu, cfd->cpumask) {
                struct call_single_data *csd = per_cpu_ptr(cfd->csd, cpu);
 
@@ -400,7 +385,7 @@ void smp_call_function_many(const struct cpumask *mask,
        }
 
        /* Send a message to all CPUs in the map */
-       arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
+       arch_send_call_function_ipi_mask(cfd->cpumask);
 
        if (wait) {
                for_each_cpu(cpu, cfd->cpumask) {