[PATCH 5/9] smp: Provide __smp_call_function_any()

Jan Kara
2013-12-23T20:41:01Z

Provide function to call given function on any cpu from a given cpu mask
while providing own csd structure.

Signed-off-by: Jan Kara <jack@suse.cz>
---
include/linux/smp.h | 9 +++++++
kernel/smp.c | 67 +++++++++++++++++++++++++++++++++++++++--------------
2 files changed, 58 insertions(+), 18 deletions(-)

diff --git a/include/linux/smp.h b/include/linux/smp.h
index 1e8c72100eda..37aa794a93ce 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -100,6 +100,8 @@ void smp_call_function_many(const struct cpumask *mask,

int smp_call_function_any(const struct cpumask *mask,
smp_call_func_t func, void *info, int wait);
+int __smp_call_function_any(const struct cpumask *mask,
+ struct call_single_data *csd, int wait);

void kick_all_cpus_sync(void);

@@ -149,6 +151,13 @@ smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
return smp_call_function_single(0, func, info, wait);
}

+static inline int
+__smp_call_function_any(const struct cpumask *mask,
+ struct call_single_data *csd, int wait)
+{
+ return __smp_call_function_single(0, csd, wait);
+}
+
static inline void kick_all_cpus_sync(void) { }

#endif /* !SMP */
diff --git a/kernel/smp.c b/kernel/smp.c
index 2efcfa1d11ee..4c44554ff5b6 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -238,6 +238,27 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
}
EXPORT_SYMBOL(smp_call_function_single);

+static unsigned int pick_any_cpu(const struct cpumask *mask)
+{
+ unsigned int cpu = smp_processor_id();
+ const struct cpumask *nodemask;
+
+ /* Try for same CPU (cheapest) */
+ if (cpumask_test_cpu(cpu, mask))
+ return cpu;
+
+ /* Try for same node. */
+ nodemask = cpumask_of_node(cpu_to_node(cpu));
+ for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids;
+ cpu = cpumask_next_and(cpu, nodemask, mask)) {
+ if (cpu_online(cpu))
+ return cpu;
+ }
+
+ /* Any online will do */
+ return cpumask_any_and(mask, cpu_online_mask);
+}
+
/*
* smp_call_function_any - Run a function on any of the given cpus
* @mask: The mask of cpus it can run on.
@@ -256,27 +277,13 @@ int smp_call_function_any(const struct cpumask *mask,
smp_call_func_t func, void *info, int wait)
{
unsigned int cpu;
- const struct cpumask *nodemask;
int ret;

- /* Try for same CPU (cheapest) */
- cpu = get_cpu();
- if (cpumask_test_cpu(cpu, mask))
- goto call;
-
- /* Try for same node. */
- nodemask = cpumask_of_node(cpu_to_node(cpu));
- for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids;
- cpu = cpumask_next_and(cpu, nodemask, mask)) {
- if (cpu_online(cpu))
- goto call;
- }
-
- /* Any online will do: smp_call_function_single handles nr_cpu_ids. */
- cpu = cpumask_any_and(mask, cpu_online_mask);
-call:
+ preempt_disable();
+ cpu = pick_any_cpu(mask);
+ /* smp_call_function_single handles nr_cpu_ids. */
ret = smp_call_function_single(cpu, func, info, wait);
- put_cpu();
+ preempt_enable();
return ret;
}
EXPORT_SYMBOL_GPL(smp_call_function_any);
@@ -322,6 +329,30 @@ int __smp_call_function_single(int cpu, struct call_single_data *csd, int wait)
}
EXPORT_SYMBOL_GPL(__smp_call_function_single);

+/*
+ * __smp_call_function_any - Run a function on any of the given cpus
+ * @mask: The mask of cpus it can run on.
+ * @csd: Pre-allocated and setup data structure
+ * @wait: If true, wait until function has completed.
+ *
+ * Like smp_call_function_any() but allow caller to pass in a pre-allocated
+ * data structure.
+ */
+int __smp_call_function_any(const struct cpumask *mask,
+ struct call_single_data *csd, int wait)
+{
+ unsigned int cpu;
+ int ret;
+
+ preempt_disable();
+ cpu = pick_any_cpu(mask);
+ /* smp_call_function_single handles nr_cpu_ids. */
+ ret = __smp_call_function_single(cpu, csd, wait);
+ preempt_enable();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__smp_call_function_any);
+
/**
* smp_call_function_many(): Run a function on a set of other CPUs.
* @mask: The set of cpus to run on (only runs on online subset).
--
1.8.1.4