[PATCH 02/13] perf: Simplify perf_pmu_register() error path

Peter Zijlstra
2023-11-02T15:33:15Z

The error path of perf_pmu_register() is of course very similar to a
subset of perf_pmu_unregister(). Extract this common part in
perf_pmu_free() and simplify things.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/events/core.c | 51 ++++++++++++++++++++++++---------------------------
1 file changed, 24 insertions(+), 27 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11426,20 +11426,35 @@ static int pmu_dev_alloc(struct pmu *pmu
static struct lock_class_key cpuctx_mutex;
static struct lock_class_key cpuctx_lock;

+static void perf_pmu_free(struct pmu *pmu)
+{
+ free_percpu(pmu->pmu_disable_count);
+ if (pmu->type >= 0)
+ idr_remove(&pmu_idr, pmu->type);
+ if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) {
+ if (pmu->nr_addr_filters)
+ device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
+ device_del(pmu->dev);
+ put_device(pmu->dev);
+ }
+ free_pmu_context(pmu);
+}
+
int perf_pmu_register(struct pmu *pmu, const char *name, int type)
{
int cpu, ret, max = PERF_TYPE_MAX;

+ pmu->type = -1;
+
mutex_lock(&pmus_lock);
ret = -ENOMEM;
pmu->pmu_disable_count = alloc_percpu(int);
if (!pmu->pmu_disable_count)
goto unlock;

- pmu->type = -1;
if (WARN_ONCE(!name, "Can not register anonymous pmu.\n")) {
ret = -EINVAL;
- goto free_pdc;
+ goto free;
}

pmu->name = name;
@@ -11449,23 +11464,22 @@ int perf_pmu_register(struct pmu *pmu, c

ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
if (ret < 0)
- goto free_pdc;
+ goto free;

WARN_ON(type >= 0 && ret != type);

- type = ret;
- pmu->type = type;
+ pmu->type = ret;

if (pmu_bus_running && !pmu->dev) {
ret = pmu_dev_alloc(pmu);
if (ret)
- goto free_idr;
+ goto free;
}

ret = -ENOMEM;
pmu->cpu_pmu_context = alloc_percpu(struct perf_cpu_pmu_context);
if (!pmu->cpu_pmu_context)
- goto free_dev;
+ goto free;

for_each_possible_cpu(cpu) {
struct perf_cpu_pmu_context *cpc;
@@ -11511,17 +11525,8 @@ int perf_pmu_register(struct pmu *pmu, c

return ret;

-free_dev:
- if (pmu->dev && pmu->dev != PMU_NULL_DEV) {
- device_del(pmu->dev);
- put_device(pmu->dev);
- }
-
-free_idr:
- idr_remove(&pmu_idr, pmu->type);
-
-free_pdc:
- free_percpu(pmu->pmu_disable_count);
+free:
+ perf_pmu_free(pmu);
goto unlock;
}
EXPORT_SYMBOL_GPL(perf_pmu_register);
@@ -11538,15 +11543,7 @@ void perf_pmu_unregister(struct pmu *pmu
synchronize_srcu(&pmus_srcu);
synchronize_rcu();

- free_percpu(pmu->pmu_disable_count);
- idr_remove(&pmu_idr, pmu->type);
- if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) {
- if (pmu->nr_addr_filters)
- device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
- device_del(pmu->dev);
- put_device(pmu->dev);
- }
- free_pmu_context(pmu);
+ perf_pmu_free(pmu);
mutex_unlock(&pmus_lock);
}
EXPORT_SYMBOL_GPL(perf_pmu_unregister);