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Subject[PATCH v5 16/20] perf: Add a helper for looking up pmus by type
Date
This patch adds a helper for looking up a registered pmu by its type.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
---
kernel/events/core.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index d4057dff27..92da1aecc7 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6963,6 +6963,18 @@ void perf_pmu_unregister(struct pmu *pmu)
}
EXPORT_SYMBOL_GPL(perf_pmu_unregister);

+/* call under pmus_srcu */
+static struct pmu *__perf_find_pmu(u32 type)
+{
+ struct pmu *pmu;
+
+ rcu_read_lock();
+ pmu = idr_find(&pmu_idr, type);
+ rcu_read_unlock();
+
+ return pmu;
+}
+
struct pmu *perf_init_event(struct perf_event *event)
{
struct pmu *pmu = NULL;
@@ -6971,9 +6983,7 @@ struct pmu *perf_init_event(struct perf_event *event)

idx = srcu_read_lock(&pmus_srcu);

- rcu_read_lock();
- pmu = idr_find(&pmu_idr, event->attr.type);
- rcu_read_unlock();
+ pmu = __perf_find_pmu(event->attr.type);
if (pmu) {
if (!try_module_get(pmu->module)) {
pmu = ERR_PTR(-ENODEV);
--
2.1.0


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