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Message-Id: <20241104135518.090915501@infradead.org>
Date: Mon, 04 Nov 2024 14:39:14 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: mingo@...nel.org,
lucas.demarchi@...el.com
Cc: linux-kernel@...r.kernel.org,
peterz@...radead.org,
willy@...radead.org,
acme@...nel.org,
namhyung@...nel.org,
mark.rutland@....com,
alexander.shishkin@...ux.intel.com,
jolsa@...nel.org,
irogers@...gle.com,
adrian.hunter@...el.com,
kan.liang@...ux.intel.com
Subject: [PATCH 05/19] perf: Simplify perf_pmu_register() error path
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@...radead.org>
---
kernel/events/core.c | 66 ++++++++++++++++++++++-----------------------------
1 file changed, 29 insertions(+), 37 deletions(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11540,11 +11540,6 @@ static int perf_event_idx_default(struct
return 0;
}
-static void free_pmu_context(struct pmu *pmu)
-{
- free_percpu(pmu->cpu_pmu_context);
-}
-
/*
* Let userspace know that this PMU supports address range filtering:
*/
@@ -11771,25 +11766,38 @@ static bool idr_cmpxchg(struct idr *idr,
return true;
}
+static void perf_pmu_free(struct pmu *pmu)
+{
+ free_percpu(pmu->pmu_disable_count);
+ 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_percpu(pmu->cpu_pmu_context);
+}
+
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;
}
if (WARN_ONCE(pmu->scope >= PERF_PMU_MAX_SCOPE, "Can not register a pmu with an invalid scope.\n")) {
ret = -EINVAL;
- goto free_pdc;
+ goto free;
}
pmu->name = name;
@@ -11799,24 +11807,23 @@ int perf_pmu_register(struct pmu *pmu, c
ret = idr_alloc(&pmu_idr, NULL, 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;
atomic_set(&pmu->exclusive_cnt, 0);
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;
@@ -11857,8 +11864,10 @@ int perf_pmu_register(struct pmu *pmu, c
/*
* Now that the PMU is complete, make it visible to perf_try_init_event().
*/
- if (!idr_cmpxchg(&pmu_idr, pmu->type, NULL, pmu))
- goto free_context;
+ if (!idr_cmpxchg(&pmu_idr, pmu->type, NULL, pmu)) {
+ ret = -EINVAL;
+ goto free;
+ }
list_add_rcu(&pmu->entry, &pmus);
ret = 0;
@@ -11867,20 +11876,10 @@ int perf_pmu_register(struct pmu *pmu, c
return ret;
-free_context:
- free_percpu(pmu->cpu_pmu_context);
-
-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:
+ if (pmu->type >= 0)
+ idr_remove(&pmu_idr, pmu->type);
+ perf_pmu_free(pmu);
goto unlock;
}
EXPORT_SYMBOL_GPL(perf_pmu_register);
@@ -11899,14 +11898,7 @@ void perf_pmu_unregister(struct pmu *pmu
synchronize_srcu(&pmus_srcu);
synchronize_rcu();
- free_percpu(pmu->pmu_disable_count);
- 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);
}
EXPORT_SYMBOL_GPL(perf_pmu_unregister);
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