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Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/membarrier.c63
1 files changed, 20 insertions, 43 deletions
diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c
index fced54ad0f3d..a39bed2c784f 100644
--- a/kernel/sched/membarrier.c
+++ b/kernel/sched/membarrier.c
@@ -66,7 +66,6 @@ void membarrier_exec_mmap(struct mm_struct *mm)
static int membarrier_global_expedited(void)
{
int cpu;
- bool fallback = false;
cpumask_var_t tmpmask;
if (num_online_cpus() == 1)
@@ -78,15 +77,8 @@ static int membarrier_global_expedited(void)
*/
smp_mb(); /* system call entry is not a mb. */
- /*
- * Expedited membarrier commands guarantee that they won't
- * block, hence the GFP_NOWAIT allocation flag and fallback
- * implementation.
- */
- if (!zalloc_cpumask_var(&tmpmask, GFP_NOWAIT)) {
- /* Fallback for OOM. */
- fallback = true;
- }
+ if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
+ return -ENOMEM;
cpus_read_lock();
rcu_read_lock();
@@ -117,18 +109,15 @@ static int membarrier_global_expedited(void)
if (p->flags & PF_KTHREAD)
continue;
- if (!fallback)
- __cpumask_set_cpu(cpu, tmpmask);
- else
- smp_call_function_single(cpu, ipi_mb, NULL, 1);
+ __cpumask_set_cpu(cpu, tmpmask);
}
rcu_read_unlock();
- if (!fallback) {
- preempt_disable();
- smp_call_function_many(tmpmask, ipi_mb, NULL, 1);
- preempt_enable();
- free_cpumask_var(tmpmask);
- }
+
+ preempt_disable();
+ smp_call_function_many(tmpmask, ipi_mb, NULL, 1);
+ preempt_enable();
+
+ free_cpumask_var(tmpmask);
cpus_read_unlock();
/*
@@ -143,7 +132,6 @@ static int membarrier_global_expedited(void)
static int membarrier_private_expedited(int flags)
{
int cpu;
- bool fallback = false;
cpumask_var_t tmpmask;
struct mm_struct *mm = current->mm;
@@ -168,15 +156,8 @@ static int membarrier_private_expedited(int flags)
*/
smp_mb(); /* system call entry is not a mb. */
- /*
- * Expedited membarrier commands guarantee that they won't
- * block, hence the GFP_NOWAIT allocation flag and fallback
- * implementation.
- */
- if (!zalloc_cpumask_var(&tmpmask, GFP_NOWAIT)) {
- /* Fallback for OOM. */
- fallback = true;
- }
+ if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
+ return -ENOMEM;
cpus_read_lock();
rcu_read_lock();
@@ -195,20 +176,16 @@ static int membarrier_private_expedited(int flags)
continue;
rcu_read_lock();
p = rcu_dereference(cpu_rq(cpu)->curr);
- if (p && p->mm == mm) {
- if (!fallback)
- __cpumask_set_cpu(cpu, tmpmask);
- else
- smp_call_function_single(cpu, ipi_mb, NULL, 1);
- }
+ if (p && p->mm == mm)
+ __cpumask_set_cpu(cpu, tmpmask);
}
rcu_read_unlock();
- if (!fallback) {
- preempt_disable();
- smp_call_function_many(tmpmask, ipi_mb, NULL, 1);
- preempt_enable();
- free_cpumask_var(tmpmask);
- }
+
+ preempt_disable();
+ smp_call_function_many(tmpmask, ipi_mb, NULL, 1);
+ preempt_enable();
+
+ free_cpumask_var(tmpmask);
cpus_read_unlock();
/*
@@ -264,7 +241,7 @@ static int sync_runqueues_membarrier_state(struct mm_struct *mm)
struct rq *rq = cpu_rq(cpu);
struct task_struct *p;
- p = rcu_dereference(&rq->curr);
+ p = rcu_dereference(rq->curr);
if (p && p->mm == mm)
__cpumask_set_cpu(cpu, tmpmask);
}