cfd->cpumask_ipi is used only in smp_call_function_many().The existing
comment around it says that this additional mask is used because
cfd->cpumask can get overwritten.
There is no reason why the cfd->cpumask can be overwritten, since this
is a per_cpu mask; nobody can change it but us and we are
called with preemption disabled.
Signed-off-by: Preeti U Murthy <pre...@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Ingo Molnar <mi...@elte.hu>
Cc: Xiao Guangrong <xiaoguangr...@cn.fujitsu.com>
Cc: srivatsa.b...@linux.vnet.ibm.com
Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Rusty Russell <ru...@rustcorp.com.au>
---
kernel/smp.c | 14 +-------------
1 file changed, 1 insertion(+), 13 deletions(-)
diff --git a/kernel/smp.c b/kernel/smp.c
index 4dba0f7..89be6e6 100644
--- 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);
@@ -47,9 +46,6 @@ 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)))
- return notifier_from_errno(-ENOMEM);
cfd->csd = alloc_percpu(struct call_single_data);
if (!cfd->csd) {
free_cpumask_var(cfd->cpumask);
@@ -64,7 +60,6 @@ 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
@@ -410,13 +405,6 @@ 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);
struct call_single_queue *dst =
@@ -433,7 +421,7 @@ 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) {
--
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