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perf/core: Simplify perf_pmu_register()

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Using the previously introduced perf_pmu_free() and a new IDR helper,
simplify the perf_pmu_register error paths.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20241104135518.198937277@infradead.org
This commit is contained in:
Peter Zijlstra 2024-11-04 14:39:15 +01:00 committed by Ingo Molnar
parent 8f4c4963d2
commit 6c8b0b835f
2 changed files with 46 additions and 42 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

17
include/linux/idr.h
View file

@ -15,6 +15,7 @@
#include <linux/radix-tree.h>
#include <linux/gfp.h>
#include <linux/percpu.h>
#include <linux/cleanup.h>
struct idr {
struct radix_tree_root idr_rt;
@ -124,6 +125,22 @@ void *idr_get_next_ul(struct idr *, unsigned long *nextid);
void *idr_replace(struct idr *, void *, unsigned long id);
void idr_destroy(struct idr *);
struct __class_idr {
struct idr *idr;
int id;
};
#define idr_null ((struct __class_idr){ NULL, -1 })
#define take_idr_id(id) __get_and_null(id, idr_null)
DEFINE_CLASS(idr_alloc, struct __class_idr,
if (_T.id >= 0) idr_remove(_T.idr, _T.id),
((struct __class_idr){
.idr = idr,
.id = idr_alloc(idr, ptr, start, end, gfp),
}),
struct idr *idr, void *ptr, int start, int end, gfp_t gfp);
/**
* idr_init_base() - Initialise an IDR.
* @idr: IDR handle.

71
kernel/events/core.c
View file

@ -11914,52 +11914,49 @@ static void perf_pmu_free(struct pmu *pmu)
free_percpu(pmu->cpu_pmu_context);
}
int perf_pmu_register(struct pmu *pmu, const char *name, int type)
DEFINE_FREE(pmu_unregister, struct pmu *, if (_T) perf_pmu_free(_T))
int perf_pmu_register(struct pmu *_pmu, const char *name, int type)
{
int cpu, ret, max = PERF_TYPE_MAX;
int cpu, max = PERF_TYPE_MAX;
pmu->type = -1;
struct pmu *pmu __free(pmu_unregister) = _pmu;
guard(mutex)(&pmus_lock);
mutex_lock(&pmus_lock);
ret = -ENOMEM;
pmu->pmu_disable_count = alloc_percpu(int);
if (!pmu->pmu_disable_count)
goto unlock;
return -ENOMEM;
if (WARN_ONCE(!name, "Can not register anonymous pmu.\n")) {
ret = -EINVAL;
goto free;
}
if (WARN_ONCE(!name, "Can not register anonymous pmu.\n"))
return -EINVAL;
if (WARN_ONCE(pmu->scope >= PERF_PMU_MAX_SCOPE, "Can not register a pmu with an invalid scope.\n")) {
ret = -EINVAL;
goto free;
}
if (WARN_ONCE(pmu->scope >= PERF_PMU_MAX_SCOPE,
"Can not register a pmu with an invalid scope.\n"))
return -EINVAL;
pmu->name = name;
if (type >= 0)
max = type;
ret = idr_alloc(&pmu_idr, NULL, max, 0, GFP_KERNEL);
if (ret < 0)
goto free;
CLASS(idr_alloc, pmu_type)(&pmu_idr, NULL, max, 0, GFP_KERNEL);
if (pmu_type.id < 0)
return pmu_type.id;
WARN_ON(type >= 0 && ret != type);
WARN_ON(type >= 0 && pmu_type.id != type);
pmu->type = ret;
pmu->type = pmu_type.id;
atomic_set(&pmu->exclusive_cnt, 0);
if (pmu_bus_running && !pmu->dev) {
ret = pmu_dev_alloc(pmu);
int ret = pmu_dev_alloc(pmu);
if (ret)
goto free;
return ret;
}
ret = -ENOMEM;
pmu->cpu_pmu_context = alloc_percpu(struct perf_cpu_pmu_context);
if (!pmu->cpu_pmu_context)
goto free;
return -ENOMEM;
for_each_possible_cpu(cpu) {
struct perf_cpu_pmu_context *cpc;
@ -12000,32 +11997,22 @@ int perf_pmu_register(struct pmu *pmu, const char *name, int type)
/*
* Now that the PMU is complete, make it visible to perf_try_init_event().
*/
if (!idr_cmpxchg(&pmu_idr, pmu->type, NULL, pmu)) {
ret = -EINVAL;
goto free;
}
if (!idr_cmpxchg(&pmu_idr, pmu->type, NULL, pmu))
return -EINVAL;
list_add_rcu(&pmu->entry, &pmus);
ret = 0;
unlock:
mutex_unlock(&pmus_lock);
return ret;
free:
if (pmu->type >= 0)
idr_remove(&pmu_idr, pmu->type);
perf_pmu_free(pmu);
goto unlock;
take_idr_id(pmu_type);
_pmu = no_free_ptr(pmu); // let it rip
return 0;
}
EXPORT_SYMBOL_GPL(perf_pmu_register);
void perf_pmu_unregister(struct pmu *pmu)
{
mutex_lock(&pmus_lock);
list_del_rcu(&pmu->entry);
idr_remove(&pmu_idr, pmu->type);
mutex_unlock(&pmus_lock);
scoped_guard (mutex, &pmus_lock) {
list_del_rcu(&pmu->entry);
idr_remove(&pmu_idr, pmu->type);
}
/*
* We dereference the pmu list under both SRCU and regular RCU, so